Transcript
t*f*
r\ *&!*
W
GopyrightlSl?
COPYRIGHT DEPOSIT
BENCH WORK IN WOOD A COURSE OF
STUDY AND PRACTICE DESIGNED FOR THE USE OF SCHOOLS AND COLLEGES
BY
W.
M. GOSS, M.S., D.Eng.
F.
Dean of the Schools of Engineering, Purdue University Lafayette, Indiana
REVISED EDITION
GINN & COMPANY BOSTON
•
NEW YORK CHICAGO LONDON •
•
ucr. 24 .HHwrUtill
OOP*
Copyright,
W.
«yu5 SJIXSJI
S»
by
1887, 1905,
M. GOSS
F.
ALL RIGHTS RESERVED
m\\t atftenacum jgregg
GINN & COMPANY
TRO-
BOSTON
U.S.A.
PRIETORS
•
PREFACE.
TO
avoid
confusion, the subject
sidered in three divisions.
Part
I.
common bench
concerning
facts
tial
herein
treated
is
con-
contains the essen-
tools
for
wood
;
it
describes their action, explains their adjustments, and shows
how of
they
may be kept
practice
quired
by which
and Part
;
Part
in order.
use
ability to
II.
the
presents a course tools
may be
ac-
such forms and adaptations
III. discusses
of joints as will meet the requirements of ordinary construction.
It is
not expected that the student
before entering
I.
before
II.
in using
upon Part
commencing
them
together.
will
complete Part
or that he will finish Part
II.,
He
Part III.
will find greater profit
For example, a shop exercise involv-
ing the chisel (Part II.) should be accompanied or preceded
by a study of the
chisel (Part I.)
;
again, the various forms
of mortise-and-tenon joints (Part III.) will be better
stood and more easily remembered,
if
under-
considered during the
time when types of such joints are under construction in the
shops (Part II.).
In the writer's experience with classes of
students, one hour has five
been given
hours given to shop work.
I.
and
is
in progress in the shops.
III.
can be mastered
The equipment
to class-room
By
this
work
for every
apportionment, Parts
in the class-room while Part II.
necessary for carrying out the course
of
PREFACE.
iv
practice given in Part II. first
is
much
Besides a bench, a pair of
appear.
hook, the following-named tools are
i
2-ft.
expensive than
less
Rule,
i
trestles,
needed
:
may
at
and a bench-
—
24-inch Ripping-Saw, 6 teeth.
1
10-inch Back-Saw.
i
Framing-Square, 7-inch Try-Square,
1
8-inch Drawing- Knife.
i
8-inch Bevel.
1
Fore-Plane.
1
Jack-Plane.
i
8-inch Marking-Gauges, Chalk-Line, with Chalk,
1
Smooth-Plane.
i
Lead-Pencil,
1
Set Auger-Bits, J" to 1" by
i
Scriber. 1
Bit-Brace.
i
2
i6ths.
Firmer-Chisels, .//
Gouges, i
22-inch
i
each, ^", \",
i
and
3lf
i
each,
Cross-cutting-Saw,
teeth.
1
pair 8-inch Dividers.
1
pair
I
1
Brad-Awl.
1
Carpenter's
1
Mallet.
1
Nail-Set.
1
Oilstone.
1
Hand-Scraper.
\ doz. Quill Bits, assorted from |"
-inch Matching- Planes.
down.
3
1
T g-inch Beading-Plane. i-inch Beading-Plane.
I
Miter-Box.
1
Plow.
I
Grindstone.
1
if provision
is
to
Hammer.
be made
for
more than one
student, the
One
items printed in small type need not be duplicated. of these will suffice for any
The
writer
is
number
less
than
set
thirty.
indebted to Mr. M. Golden, of the School
of Mechanics and Engineering, Purdue University, for the execution of
many
of the drawings and for valuable suggestions.
W. Purdue University, Lafayette, Ind.
1887
F.
M. G.
PREFACE TO SECOND EDITION.
In the preparation of this edition the text has been revised
and a new section dealing with timber and use has been added.
with Parts
I
and
its
preparation for
This appears as Part IV and, in
III, is
common
designed for use in connection with the
Use has been made
course of practice outlined in Part II.
of
Snow's " Principal Species of Wood," from which several of the illustrations of Part
IV have been taken or adapted, and
of certain publications of the cially those
Fernow.
also
United States government, espe-
prepared by Professor C.
S.
Sargent and Dr. B. E.
CONTENTS
INTRODUCTION.
[.
2.
4.
Method
OF
ken Drawings.
—
Scale.
7.
PART Bench. 13.
—
I.
—
8.
— n.
Vise.
Sections.
5.
—
6.
Bro-
Dimension Lines,
Dimensions.
— BENCH
Bench-Stop.
10.
—
Incomplete Sections.
Cross-hatching.
PAGES
3.
of showing Parts Obscured from Sight.
Section Lines.
9.
— INTERPRETATION
MECHANICAL DRAWINGS. Plans. — Elevations. Mechanical Drawings Defined. —
1-6
TOOLS.
—
12.
Bench-Hook.
—
Trestles
7-9
Measuring and Lining Appliances. 14.
Early Standards of Length.
—
15.
English Standard Yard.
— Framing-Square. —
United States Standard of Length.
— — 24.
18. Rules.
21.
— 19.
Brace-measure Table.
"Miter-Square."
—
—
17.
20.
The Troughton
— 16. Scale.
Board-measure Table.
—
—
— 22.
Try-Square. 23. Bevel. 26. Di25. Try-and-" Miter " Square.
—
—
with Dividers. 28. Combining Square Combining Square and Bevel. 30. Setting the Bevel at an Angle of 60 Degrees. 31. Setting the Bevel at any Given Angle. 32. Marking-Gauge. ^3- Mortise-Gauge. -— 34. Panel-Gauge. 36. Chalk-Line. 35. Cutting-Gauge. viders.
27. Scribing
and Rule.
—
—
29.
—
—
37.
Scriber.
—
38.
—
—
Pencil
—
—
.
9-20
CONTENTS.
Vlll
Chisels and Chisel-like Tools. 39.
— 40.
Firmer-Chisels.
Framing-Chisels.
—
41. Corner-Chisels.
— 44. Drawing-Knife. — 45. Angle of Cutting Wedge in Action of Cutting Wedges. — 20-26 Chisel and Gouge. — 47. Grinding. — 48. Whetting — 43.
42. Gouges.
Chisel Handles. 46.
,
.
.
—
53.
Saws. 49.
Efficiency.
—
Form.
50.
—
51. Set.
— 52.
Size of Teeth.
Ripping-Saw and Cross-Cutting-Saw Defined.
—
Ripping-Saws.
—
Saw.
55.
—
Teeth of Cross-Cutting-Saws.
54.
—
Teeth of 56.
Compass-Saw
57.
Back,
,
26-36
Appliances for Filing and Setting Saws. 58.
—
Files.
Bending the Tooth. Clamps
59. Sets for
the Tooth.
— 61.
Saw 62 Top-Jointing.
— 63.
and
Filing
Setting.
—
— 60.
Sets for
Swedging 36-38
Setting.
64. Filing.
— 65.
Side- Jointing, 39-41
Planes and Plane-like Tools. 66.
—
Description of Planes.
67.
Angle of Cutting Wedge.
Length of Stock.
— 69.
—
68. Plane-Iron.
Outline of Cutting Edge.
—
—
70.
71. Action of Smooth- Plane Use of Different Bench Planes. and Fore- Plane Compared. 72. The Cap. 73. Narrowness of
—
Mouth.
— 74.
Iron Planes.
Adjusting the Iron.
—
Circular-Planes.
77.
—
Rabbeting-Planes.
— 84. Planes. —
Rounds. tion
Planes of 79.
—
—
75. Jointing a Plane.
Wood and
Block-Planes.
—
Iron Combined. 80. Spokeshaves.
Matching-Planes.
82.
Beading- Planes. 87.
—
— 85.
—
Plows.
83.
— —
76. 78.
— 81.
Hollows and
— 86.
Combina-
Scrapers
4 I_ 5 2
Boring Tools. 88.
Augers. Bits.
—
— 90. Sharpening Augers and Auger— 92. Expansive — 93. Small Bit-Braces. — 95. Angular Bit-Stock. — 96. Automatic — 89.
— 91.
94.
Auger-Bits.
Center-Bits.
Boring Tool
Bits.
Bits.
53—59
CONTENTS.
IX
Miscellaneous Tools.
— 99. Brace Screw— 102. Mallet. — Miter-Box. — 105. Iron 103. Sana-Paper. — 104. Wooden Miter-Box. — 106. Clamps. — 107. Grindstone. — 108. Use of Water on a Grindstone. — 109. Truing a Grindstone. — no. Truing Devices Grindstones. — in. Oilstones. — 112. Oil Oilstones. — 113. Form of Oilstones. — 114. Oilstone — 115. Truing an Oilstone 59-69
97. Winding-Sticks.
Driver.
— 100.
— 98.
Hand
Hammer.
Screw-Driver.
— 101.
Hatchet.
for
for
Slips.
PART [16.
II.
— BENCH
Good Lines
a Necessity.
Jointed Face.
— 119.
EXERCISE
— 117.
WORK.
Location of Points.
—
118.
Working- Face
No.
1.
71—73
— Measuring
and
Lining.
— 122. Lining: — 123. Chalk- Lining. — Lin— 125. Lining: Pencil and Bevel. — 126. "Gauging" Lines: Pencil and Rule. — 127. Spacing: Scriber and Rule. — 128. Lining: Scriber, and Try-Square. 129. Lining: Scriber and Bevel. — 130. Gauge-Lining. — 131.
120. Material.
— 121.
Spacing: Pencil and Rule.
and Framing-Square. ing: Pencil, and Try-Square. Pencil,
124.
Lining for Exercise No. 3
EXERCISE 132. Chiseling by Hand.
No.
73—79 2.
— 133.
— Chiseling
and Gouging.
Chiseling by Use of Mallet.
— 134.
Gouging
80-83
— Sawing. Handling the Saw. — 136. Guiding the Saw. — 137. ing the Angle of the Cut. — Rip-Sawing. — EXERCISE
135.
No.
3.
138.
Correct-
139. Cross-
cutting
83-86
EXERCISE 140.
Handling the Plane. ing.
— 143.
—
141.
No.
4.
Why
Planing to a Square.
— Planing.
a Plane Clogs.
— 144.
—
142. Joint-
Method of Performing
CONTENTS.
X
Similar Operations.
— 145.
Smooth
Surfaces.
PAGES
—
146.
Sand86-91
Papering
EXERCISE 147. Jointing to Width.
—
Hammer
150.
drawing Nails. the Box.
—
— 154.
to
153. Fastening the
—
158.
—
167.
— 165.
Making a
EXERCISE 169. Lining
9
No.
No.
7.
— Halved
8.
Fit.
No.
and Cutting.
—
168.
10.
— Keyed
-=-
72.
EXERCISE and Cutting
No.
96-98
159. Cut-
99-102
.
Splice.
....
103, 104
Mortise-and-Tenon Joint.
— 166.
Cutting the Tenon.
104-110
Mortise-and-Tenon Joint. no, in
Key
No. 1
—
Toeing Nails
Drawboring
— 170.
and Cutting.
Illustrated.
— 161.
— Splayed
Cutting the Mortise. Pin.
....
Splice.
and Finishing the Joint
Lining and Cutting the Joint
174. Lining
— Bench-Hook.
Using the Auger-Bit
— Simple
EXERCISE 171. Lining
6.
Sawing a
163. Cutting
Finishing
91-96
Value of Working-Face
— 160.
EXERCISE No. 164. Lining.
No.
— 156.
EXERCISE 162. Lining.
Box Bottom.
End Grain
Planing
and Sawing.
ting the Joint.
— Box.
— 148. Sawing Length. — 149. Nailing. — 151. Setting Nails. — 152. With-
EXERCISE 157. Lining.
5.
Marks.
EXERCISE 155. Lining
No.
— Plain Dovetail. Gluing. — 173. Short Method
ii.
.
12.
.
— Lap
.
of 1 1
2, 1
13
Dovetail. 114.
i J
5
CONTENTS.
XI
PAGES
EXERCISE 175.
Lining and Cutting.
— 176. A Modified Form of the Joint
EXERCISE 177.
Panel Door Described.
and
—
Rail.
14.
— 17S.
Inserting Screws.
Making
Making the
—
187.
III.
—
180.
Joint between Stile
Keying the
Joint.
Fastening Panel to Frame.
183.
Using the Brad- Awl
No. 15.—
.
117-121
.
Frame and Panel.
and Rail. Forming the Panel
Joint between Stile
Beading.
PART
—
115-117
.
— Frame and Panel.
Cutting Chamfers.
EXERCISE 184.
No.
Finishing the Panel.
181.
182.
— 179.
No. 13.— Blind Dovetail.
— ELEMENTS
— 185.
Plowing.
—
186.
121-124
OF WOOD CON-
STRUCTION. CARPENTRY. 188.
Work
—
and Joiner Compared. 189. Congressional, Tensional, and Transverse Stress Defined. 190. Effect Neutral Axis. Relation between the of Transverse Stress. of Carpenter
—
Depth of a Timber and
—
191.
Resistance to Transverse Stress.
its
Rankine's Principles concerning Joints and Fasten-
125-128
ings
Joints Connecting Timbers in the Direction of their Length. 192.
Lapped
Joint.
— 193.
Fished Joint.
195. Scarfed Joint for Resisting
Joint for Resisting Tension.
—
—
— 194.
Scarfed Joints.
Compression.
197.
—
196. Scarfed
Scarfed Joint for Resisting
^ 198. Scarfed Joint for Resisting Tenand Compression. 199. Scarfed Joint for Resisting 1 28-1 31 Tension and Transverse Stress Transverse Stresses.
sion
—
CONTENTS.
Xll
Joints Connecting Timbers at Right Angles.
— 201.
— 202. Cogging. — 203. Mortise— 204. Mortise and Tenon Joining a Vertical to a Horizontal Timber. — 205. Mortise and Tenon Joining a Horizontal to a Vertical Timber. — 206. Mortise and Tenon
200. Halving.
Notching.
and-Tenon Joints.
Joining
One Horizontal Timber
to Another.
Tusk Tenon 131-135
Miscellaneous Joints. and Tenon. Chase Mortise
207. Oblique Mortise Joint.
— 210.
— 208.
Bridle Joint.
— 209. ,
.
Tie
135-137
JOINERY. 211. Joinery Described
137
Beads and Moldings. 212.
— 213. Use of Beads. — 214. Chamfer. — 215. Stop — 216. Moldings Described. — 217. Round Nose. — 219. Joints Some Typical Forms of Moldings.
Beads.
Chamfer. 218.
Fillet.
in Joinery
Defined
138-140
Heading-Joints, or Joints Uniting Pieces in the Direction of their Length. 220.
Square Heading- Joint.
Splayed Heading- Joint
141
Joints Uniting Pieces in Direction of their Width. 221. Their Office. Joint. ing.
— 222.
— 225.
Butt Joint.
Filleted Joint.
Rabbeted
— 223. Glued Butt Joint. — 224. CleatSide Cleats. — 226. End Cleats. — 227. Relieving
Matched
Joint.
Cleats from Strain
141-144
CONTENTS.
Xlll
Joints Uniting Pieces at Right Angles.
— 229. Miter — 230. Strengthening of Miter — 231. Dovetail — 232. Proportions of Mortise— 233. Single and Double Tenons. — 234. and-Tenon Haunching. — 235. Four Tenons. — 236. Mortises and Tenons at an Angle the Work. — 237. Modifications of Mortise-and-
228. Butt Joint.
Joint.
Joints.
Joints.
Joints.
in
Tenon
144-148
Joints
Paneling. 238. Panel.
— 239.
Frame.
— 240.
Joints
between
Panel
Frame
and 148-151
FASTENINGS. 241.
Wedges. — 243. Blind-Wedging. — 244. Keys. 245. Dowels. — 246. Nails. — 247. Size of Nails. — 248. Brads. — 249. Tacks. — 250. Screws. — Glue 151-157 Pins. — 242.
251.
PART IV.— TIMBER AND ITS PREPARATION FOR USE. Timber.
— 253. Structure of Wood. — 254. — 255. Adaptability of Various Woods
252. Timber.
Wood.
Markings of 158-166 .
.
.
Characteristics of Typical Timber-Yielding Trees.
— 257. Exogens. — 258. Effect of En— 259. Broad-Leaved Woods. — 260. Oak. — 261. White Oak. — 262. Red Oak.— 263. Maple. — 264. Sugar Maple. — 265. Silver or White Maple. — 266. Black Walnut. — 267. Yellow Poplar. — 268. Beech. — 269. Ash. — 270. White Ash. — 271. Needle-Leaved Woods. — 272. Pine. — 273. White
256. Classification of Trees.
vironment.
CONTENTS.
XIV
Pine. — 274. Long-Leaved Pine. — 275. Short-Leaved Pine. — 276. Loblolly Pine. — 277. Bull Pine. — 278. The Spruces. — 279. Black Spruce. — 280. White Spruce. — 281. Hemlock. — 282. Eastern Hemlock. — 283. Western Hemlock. — 284. Bald Cypress. — 285. The Common Redwood. — 286. The
Big-Tree Variety of
Redwood
166-182
Logging.
— 288. Transportation of Logs. — 289. Saw— 290. Process of Sawing. — 291. Milling. — 292. WaTimber. — 293. Process of Seasoning. — 294. Air Seasoning. — 295. Steam Drying. — 296. Water Seasoning. — 297. Kiln Drying. — 298. Kilns. — 299. Shrinkage. — 300. Swelling. — 301. Warping. — 302. Decay Wood. — 303. Timber Preservation. — 304. Creosoting 182-198
287. Felling Timber. mills.
ter
in
in
-
305. Strength
of
Strength of Timber.
Timber.
— 306. Strength — 308. Strength
Strength in Compression.
Strength under Transverse Loads
in
Tension. in
Shear.
— 307. — 309. 198-200
INTRODUCTION. D^C
INTERPRETATION OF MECHANICAL DRAWINGS. Most of the
I.
presented with
illustrations
the
following
chapters are in the form of Mechanical Drawings.
may appear
novice, these
some of
;
him
To
the
but careful attention to
the principles underlying their con-
struction will enable
Fig. 1
readily to interpret
meaning.
their
A
confusing
mechanical drawing, as distinguished from
a perspective drawing, or picture, instead of giving
all
the characteristics of an object at a
them
glance, presents
view one
set
in detail, giving in
of elements,
one
another view another set of
in
elements, and so on, until the form of the object is accurately defined.
For example,
Fig.
of an object which
by
Fig. 2.
By
Fig.
i
is
a perspective view
represented mechanically
is i
it
will
that the object represented Fig. 2 there
is first
that the object
an
elevation,
From solid
is
at is
once be seen
a cylinder.
In
presented a plan, showing cylindrical;
and, secondly,
showing the height of the cylinder.
the combination of these two views, the
may be
as easily
imagined as from Fig.
and the knowledge obtained of
it is
i,
much more
definite.
A is
perspective view of an object
had by looking from some one
is
that
which
point, as
A,
ELEVATION.
Fig. 3, while a
view represented by a mechanical drawing supposes the ob-
BENCH WORK
WOOD.
IN
number of
server to be looking from an infinite
always in parallel
lines, as
A
appear
if,
standing on
natural base,
down upon
it
and
Fig. 3
Plan of any object represents it as it would 2.
points,
indicated by A, Fig. 4.
its
were looked as
vertically,
indicated by the arrows A, If the
Fig. 5.
object,
base, any one of
its
has no fixed
as a rectangular block,
faces
may be taken
as such.
Fig. *J'
3.
An
appear
if,
Fig.
v
v
I'-
i,
Elevation of any object represents standing on
its
natural base,
it
it
as
The
5.
elevation
is
angles to the pta?i.
always
at
right
There may be
several elevations of the
same
object,
each differing from the others as the point of observation changes.
For
example, the plan and elevation of the object represented by Fig. Fig.
7,
Fig. 9.
but they
6,
are usually
may be made
as
made
it
would
were looked upon in a
horizontal direction, as indicated by
arrows B, Fig.
5
as
shown by
shown by Fig. 8 or
INTRODUCTION. These angular views, indeed, cannot be avoided when the form they represent
is
so complicated that
allel,
its
faces are neither par-
nor at right angles to each Fiy;.
other.
Fig.
10
view of an object which
is
repre-
sented mechanically by Fig.
n. j
It is is
evident that
shown
in
B B
faces of face of
is
if
the
\
PLAN.
one face of A
elevation,
two
if
one
shown, two of A
will
will
9
a perspective
is
appear
;
appear.
In the representation of simple objects, the plan
is
in
some cases
omitted, and two elevations employed.
These may be designated
as side elevation
and end
BENCH WORK
4
than at the bottom, the drawing if
smaller at the top, as
Fig. 12
will
shown by
IN
WOOD.
appear as shown by Fig. 14 In Fig. 16 dotted
Fig. 15.
INTRODUCTION. Cross-hatching parallel lines
of a section.
5
a term applied to the uniformly spaced
is
which are employed
to indicate the cut surface
See Fig. 18.
"Fig.
Different pieces of material appearing in the
same section
are
cross-hatched
angles, as in Fig. 19,
at
different
which represents a cross-
section of a lead-pencil
;
and
different kinds of
material are frequently indicated by cross-hatch-
ing in different colors.
Incomplete sections show only the cut surface, to the exclusion of
common
all
and omit the
A
other portions of the object.
to place such sections letters.
and
goblet, Fig. 2i.
It
is
section, lines,
See Fig. 20.
single view of a symmetrical object
in section,
on the
may be made
partly
partly in elevation, as in the drawing of the
BENCH WORK the object,
it is
and
The
so on.
on a
said to be
i
as frequently written,
in,
=
scale 6 in.
i
WOOD.
scale of
ft.
=
IN
;
if -J-th
1 ft.
^ inch
to the foot, or,
the size, as 2
in.
=
i ft.,
often expressed as "half
is
size.
— The
Dimensions.
8.
various dimensions of an object repre-
sented are shown on the drawing by appropriate figures, which express feet
when as
two
the
when
followed by feet,
same
followed by
Thus
".
and 2"
as
2'
',
and inches
should be read
two inches.
as twelve feet
12'
1" 7
and seven and three-
quarters inches.
The sented
figures always
show the dimensions of
the thing repre-
they do not agree with the dimensions of the drawing
;
except when the
latter is full-sized.
See dimension figures
in
Fig. 23.
Dimension
lines.
— Dimension
figures are always placed on, or
near, lines along which they apply. In drawings these lines are usually in color (red), but may be dotted black, as in Fig. 23.
When
convenient, they are placed within the outline of the
drawing at
one
;
but
side,
if
the drawing
is
small or crowded, they are placed
and are connected with the parts they
Two
pendicular, colored or dotted lines.
each side of the dimension
which line,
it
applies.
figure, locate the points
Several dimensions
each being limited by
its
limit
own
by per-
arrow-heads, one on
may be
between
given on the same
arrow-heads.
PART
I
>^<
BENCH TOOLS. Bench.
g.
length
Its
A
—A
simple form of bench
may vary from
of work to be done.
Its
the character of the
work
heavy
—
as well as
6'
is
shown by
Fig. 24.
upwards, according to the length
height
B should also
— high
for light
be regulated by
work, and low for
by the height of the person who
is
to use
it.
Carpenters' benches are usually about 33" high, while those of cabinet and pattern makers are from 2" to 4" higher. Fig:.
Scale, \i ,= 1
'Mk i
"-"
1
'" ~~ ""-
-
-
FT
1
END ELEVATION.
-
,
S4
;.—
:
BENCH WORK
8
but
it is
WOOD.
IN
have some form of iron
far better to
many
fitting,
of
which are supplied by the trade. The char-
Fij
acteristics of all of
them
by the one shown
in
A
the
let into
is
face.
are well illustrated
Fig. 25.
The frame
bench even with
C
The hook
is
sur-
its
held in position at
any height above the bench by the action
C may
B.
of the screw
be fastened even
with the surface of the bench, or removed entirely.
The Vise
11.
poses, has long
d, Fig. 24, is of
a form that, for general pur-
To
hold the work well, the jaw d
been
in use.
should be as nearly as possible parallel to the face g, against
which
it
acts.
/Fig.
If
it
is
not parallel, the space between should
be
26
less at the
tom
— an
sures a
top than at the bot-
arrangement which
much
better grip
in-
upon the
work than the opposite conditions. Adjustments
for
made by changing
parallelism
are
the pin c from
one hole to another.
Iron vises
can now be had which are adapted to the
described
same uses with the one
;
that the clamping faces always maintain their parallelism,
being
just
they can be quickly adjusted, they are so designed
stiff er
than wooden
vises,
and
they can be depended upon to
hold work more securely.
An
iron
bench
vise,
such as
is
shown by
useful for small work, and, if expense
should -supplement the vise
on the bench
The
holes,
at e,
d, in
is
Fig. 26,
is
extremely
not to be considered,
which case
it
may be
located
H. in the
which may be used while the other end
bench are
to support is
for the reception of a plug,
one end of a long piece
held by the vise.
of
work
BENCH TOOLS.
A
12.
Bench-Hook,
shown by
Fig.
178,
applied
The
sliding across the bench.
flat
A
bench
the
length of from
which
faces
bench and receive the work, should be allel.
to
as
167, provides a stop to prevent work from
Fig.
14" to 16"
on the and par-
rest
true planes
convenient, though
is
bench-workers frequently have several of different lengths.
ways to sup-
Trestles, or " horses," are used in various
13.
port
and
material,
also
to take the place of the
Qr
Fi
f—~
bench when large pieces of material are
venient
form
by Fig.
27.
is
be
to
A
operated upon.
con-
shown
Measuring and Lining Appliances. 14.
Early Standards of Length.
need of
units of measure,
nearest at hand, and
it
— To
was natural
common
meet the
to
earliest
adopt the means
consent, no doubt, brought into
use the pace, the forearm, or cubit, the foot, the hand, the nail, etc.
These were
certainly convenient enough, for wherever he
might go, every individual carried
his units of
measure with him.
Variations in their length, however, were inevitable,
attempts were English
made
statute,
to
substance
the
and many
An
old
descended
to
reduce them to a standard. of which
has
American arithmetics of modern date, enacts " that three barleycorns, round and dry, make an inch, twelve inches make a foot, three feet a yard, etc. that this
mode
;
and there seems
But setting aside the objection due individual grains,
taken,
—
it is
be no doubt
to
of obtaining a standard was actually resorted
—
number be know how much of the sharp end must be removed to make it round,' that
unless the average of a large
so difficult to
of a grain of barley
to.
to the varying size of the
'
BENCH WORK
IO the definition
not of
is
much
WOOD.
IN
Nevertheless, in spite
value.
of numerous attempts at legislation on the subject, to the year 1824,
yard of
this
covered."
down
this,
was the only process by which the standard
country [England] could,
be
if lost,
legally re-
*
Previous to the institution of a national standard of length in Great Britain, influential
men and prominent
societies pro-
vided themselves with so-called standards, which were accepted
and used
in different localities.
By comparison with many
these, the present standard of length
was made, and
From
defined by law as the British standard yard. fifty
copies have been made.
sent to the United States,
of the Coast Survey. 15.
and
1
"
Two
this,
in the
are described as follows
Each standard of length
is
:
one-half inch below the surface.
which are
The
is
One
inch from each
transversal
wells are protected
by metal
sunk
is
At the bottom of the
wells,
in diameter,
upon
and two longitudinal
lines.
a gold pin about 0.1 inch
drawn three
keeping
a solid bar 38 inches long
inch square, in transverse section.
each bar,
about
—
extremity a cylindrical well, one-half inch in diameter,
in
of
length
of these copies were in 1855
and have since been
They
its
The
caps.
English yard at a specified temperature
is
length of one
defined by the dis-
tance from the middle transversal line in one well to the middle transversal line in the other, using the parts of those lines
are
midway between
16.
the longitudinal lines."
The United States Standard
which
2
of Length.
— " The stand-
ard yard of Great Britain was lawful in the colonies before 1776. is
By
the Constitution of the United States the Congress
charged with fixing the standard of weights and measures,
but no such enactment has ever been
made by
Congress, and
1
Shelley's "
2
Report of the United States Coast Survey, 1877, Appendix No.
Workshop Appliances." 12.
BENCH TOOLS.
II
therefore that yard which was standard in England previous to
1776 remains the standard yard of the United States to
this
day."
"The Troughton Scale is a bronze bar with an inlaid made for the survey of the coast of the United by Troughton, of London. The bar is nearly 86 inches
17.
scale,
silver
States
and one- half inch thick. A thin strip of more than 0.1 inch wide, is inlaid with its surface It extends with the brass, midway the width of the bar.
long, 2\ inches wide, silver,
flush
a
little
the whole length of the bar, save where
it is
Two
one near each end.
perforations,
inch apart are ruled longitudinally on the
between them
"The
zero
is
interrupted by two
about 0.1
parallel lines
The space
silver.
divided transversely into tenths of inches.
mark of the graduations
one end of the bar.
about 3.2 inches from
is
Immediately over
surmounted by the motto,
E
it is
Pluribus
engraved an eagle,
Unum, and
thirteen
Below the 38 to 42-inch divisions is engraved Troughton, London, 1814.' The bar is also perforated by a hole above the scale and near the 40-inch division, and by one below it, stars.
'
between the words
"The
'
Troughton
and
'
'
London.'
.
.
.
yard of 36 inches, comprised between the 27th and
63d inch of the Troughton comparison
scale,
which was found by Hassler's
be equal to the average 36 inches of the scale, is the actual standard yard of the United States, having been to
adopted by the Treasury Department as such
recommendation of Mr. Hassler. 2 " 18.
usually
Rules are measuring
made
of boxwood.
strips,
Their
and are size
expressed by their length in inches or
For convenience, they are made
2
1832, on the
^^ Fis ss '
is
feet, ;
as a " 6-inch rule," a " 2-foot rule."
1
in
1
— ;
, V
to fold,
Report of the United States Coast Survey, 1877, Appendix No. 12. first superintendent of the United States Coast Survey.
Hassler was the
BENCH WORK
12
and one
when made of
six pieces.
Fig. 28
by a
four,
shows a four-fold
rule.
preserve the rule from wear, the better class are " bound"
which covers each edge
strip of brass
bound," having
when made of two pieces, and "six-fold" when made of
said to be " two- fold "
is
" four-fold"
To
WOOD.
IN
7
!,
,
lir"l 0'' l
only one
"l8
l9
J.9J 33
T
.
i
.
f Y i
.
i
.
i
.
T
i
i
.
|, l7
others are " half-
;
U l6,|,
,|l
,
l5l
U
U"l2''l
i'.nnhf. .rM.i'iii^iiniii'ii.i i
edge covered;
m
1
'^
ȣI 1 .
!,
sq
g and still others are "unbound," having no edge protection. .
Carpenters' rules are usually graduated to eighths
of inches on one side, and to sixteenths on the other. Besides the regular graduations, other numbers are frequently represented ; but their purpose is so varied that their interpretation cannot be given here. 19.
The Framing-Square,
implies,
is
would seem to belong the bench- worker it
Fig.
29, as
its
name
intended primarily for use in framing, and
;
but
to the builder rather than to its
range of usefulness makes
valuable to any worker in wood. All but the very cheapest are of steel,
nickel-plated.
The
clearness to the lines
and many are and gives
nickel prevents rust,
and
figures.
The
figures of the
graduations along the several edges, begin at the angle
and extend
to the ends of the legs.
In addition to
on one side a line of figures beginning at the end of the long leg and extending to the angle. On the reverse side, represented by Fig. 29, there is on the long leg a board-measure table, and on the
these, there
is
short leg a brace-measure table. 20.
The Board-measure Table.
— Lumber
square foot, and the value of the table of a board, or of any surface, in square feet
and
its
lies in its
feet,
breadth in inches are known.
is
sold by the
giving the area
when
its
length in
BENCH TOOLS. The
1
belong to the outside graduations,
figures that
1,
2, 3,
employed to represent the width of the board to be measured, and all the lengths included in the table are given in a column under the figure 1 2 belonging to the outand so on up
to 24, are
On
side graduations.
and
To
8.
square,
this
find the surface of
column under 12 having found
comes under
it,
10' long
Under in the
under
The
and it
figure nearest the finger in
area of the board in
— How many
.
feet.
square feet are there in a board
and 7" wide? 12 of the outside graduations, in Fig. 29, the 10
second 7
length,
that figure of the outside graduations that corre-
this line represents the 1
its
14, 10,
look in the
run the finger along in the same line until
sponds to the board's width. Exci7nple
first
number representing
a
for
29, they are
Fig.
any boara,
and the
line,
figure
of the outside graduations,
area required, in
in is
this 6,
line
is
most nearly
which represents the
feet.
—
What is the surface of a board whose length 2. and whose width is 21"? As in Example 1, look under 12 of the outside graduations for 8 in this line, under 2 1 of the outside graduations, will be found the 14 which represents the area required. The reason that the column under 12, forming, as it does, Example
is 8'
;
a part of the body of the table, will
be clear when
will
contain as
is,
it
many
is
is
surface feet as
a board 12" wide and 14' long
feet.
The
figures
given under
length to which lumber 8, 10, 14, 16,
taken to represent the length,
remembered
is
cut,
it
that
any board 12" wide
contains linear feet
;
that
will
have an area of 14 square
12
correspond to the usual
and on most squares they are
and 18; and, since the
figure representing the
area differs from the figure representing the length only be-
cause the width varies,
we must go to the right or when the width is greater
of the column under 12,
than 12.
the
left
or less
BENCH WORK
14
Fig.
30
IN
WOOD.
BENCH TOOLS. The blade
be seen by Fig. 32.
as will
angle with
beam
the
;
15
adjustable to any
is
C
thumb-screw
the
fastens
it
when
set.
The
of a bevel
size
is
expressed by the length of
its
beam
in
inches.
"Miter-Squares" derive
24.
name from tended
to serve.
struction
is
their
the purpose they are in-
A
"miter"
in con-
one-half of a right angle,
or an angle of 45 degrees. In the " miter-square " the blade, as in the try-square,
is
permanently
set,
but
an angle of 45 degrees, as shown
at
by
Fig. 33.
The
bevel, while neither so con-
venient
made
nor so
accurate,
often
is
to answer the purpose of the
25.
Square
A is
miter-square.'
Combination Try-and-" Miter " shown by Fig. 34. This, while .
34
perfect
as
square,
is
a
try-
trans-
formed into a "miter-square " the
beam
AB
against
when
of
face
the
is
placed
the
work-
ing-face (119) of the material. 26. Dividers
and
are
much used
in laying off circles
in spacing
and arcs of
The form shown by Fig. 35 dividers." The two points
is
circles.
known
as "arc
and set-screw
are held at any desired distance
from each other by the action of the set-screw A upon the B. In setting, the final adjustment may be made more
arc
BENCH WORK
16
by use of the thumb-nut C, which, acting
delicate
tion to the spring
lengthen
27
.
WOOD.
IN
it,
as
D, shortens
may be
the arc
spring to
— The
four legs
required.
Scribing with Dividers
:
Example
1
.
of a table are of unequal length, and prevent even.
in opposi-
B or allows the
from standing
it
Scribe the legs to length.
by means of blocks or wedges under the shorter legs, make the top of the table to stand parallel to some plane surface, as a bench top, or even the floor if Fig. 36 First,
it is
good condition,
in
may be
which
either of
designated as F> Fig. 36.
Set
the dividers equal to or greater than the
height of the thickest blocking, so that
F
while one point, a, touches the leg, the
other, b, will rest dividers, ea,
upon
F in the
same
which,
if
Move
vertical line.
keeping b on F, and producing by a a
line
on the
the
leg, as
the dividers are properly handled, will be parallel
to the surface F.
Without changing the dividers, mark at leg, and cut the legs to line.
least
two adjoining faces on each It is
evident that lines thus scribed will
distance from the surface
F; and
be at an equal
all
the table top, having been
made
parallel
follows
that
scribed
are
the
top,
to
the
F,
parallel
or
that
it
lines
to
the
length of the four legs, as defined is
Example
2.
—
It is
required to
the outline abed ot A, Fig. 37.
fit
by the
the end of a board
at a.
and the other
at
B to
Place the board in the position
shown, and set the dividers at a distance equal to x.
one point
lines,
the same.
e, let
them be moved
With
together,
one following the outline abed which the other produces on B,
BENCH TOOLS. Cut
as shown.
to line,
and the board
angles, as at /, enter into
be attained
base line
if
the point
17
/
will
When
sharp
is
located by measuring from the
hi.
Combining Measuring Appliances.
28.
fit.
the outline, greater accuracy will
— To
find the hypot-
enuse of a right-angled triangle when the other two sides are rule and framingshown by Fig. 38.
known, use the square,
as
Suppose ab
— 92""
Fig. 30 the length and the length ae
in
= 5^",
to f1 *1 ^ the length be,
>
apply one end of the rule to the 9^-"
mark on one
square,
and bring
mark on shown by Fig.
coincides with the
The length many purposes.
be.
Ju
0l
5-A-"
the other leg, as it
edge to
J"bJ^
coincide with the
where
leg of the
its
5-J-"
thus found will be If the
The reading
38.
mark, or io|",
will
sufficiently
of the rule
be the length accurate
distance to be measured
is
imagine every inch on the square to be equal to a read the result in
for
in feet,
foot,
and
feet.
If the proportions of the triangle are very large, the figure
may be drawn
at full size
on the shop
floor,
and the extent of
each part determined by direct measurement.
29.
Setting the Bevel.
— To
set the bevel at a miter (an angle
of 45 ), place the beam against one leg of the square and adjust the blade so that
it
will
agree with
equal distances on both legs, as
4" and 4", Fig. 39. Any distance the same on both legs.
may be
taken, but
it
must be
BENCH WORK
i8
IN
WOOD.
The carpenter frequently describes an angle to which the bevel may be set as " i in 2 " or " 1 in 4," by which is meant that while the beam is applied, as shown by Fig. 39, the blade corresponds to the 1" mark on one leg, and the 2" mark on the other or to the 1" mark on one leg, and the 4" mark on the other. 30. grees.
To
set the
;
Bevel at an Angle of 60, and of 120 Dea jointed edge a at any distance from a, gauge a
— In Fig. 40 the board A has
;
From any point
line be.
on
be,
with any radius,
use the dividers to strike the arc be,
with same
radius, strike
from b the
Place the
arc/.
beam
of the bevel against face a,
move blade
till it
co-
and the bevel is set at an angle of 60 degrees with one side of beam, and 1 20 degrees with the other. 60 degrees is the measure of the angle between any two faces of an equilateral triangle, and 120 degrees, of the angle between any two feces of a regular hexagon for these reasons, the bevel
incides with the points b and/,
;
set at these angles
31.
To
set the j,,.
is
often of use in construction.
Bevel at any given Angle. is
41
made
rectly will
—
If
an attempt
to set the bevel di-
from
on paper,
lines
be found
difficult to
it
de-
termine when the tool agrees with the drawing. to transfer such
\
It is better
an angle to a
board, from the working-edge
of which the bevel set.
Thus,
if it
is
may be required
to set the bevel at the angle
abc, Fig. 41, a board, as
A,
should be lined as follows
from the working-edge gauge the
line a'b'
;
:
with the dividers,
BENCH TOOLS. at
any convenient radius, describe from
I9 b'
the arc
e'a*
with the
;
same radius describe from b the arc ed set the dividers so that with one point on e the other will fall on/, and lay off this distance on e'd', locating/'; connect // and/'; the angle a'b'c' will be equal to abc. As a'b' is by construction parallel to the ;
working-edge of the board, the angle between the working-
edge and
b'c' is
equal to the angle abc.
If,
then, with the
of the bevel on the working-edge, the blade cide with
b'c',
The
marking-gauge.
beam
to coin-
—
Fig.
42 shows the usual form of a "spur," e, should be filed
steel point, or
narrow edge, so that
to a
made
the bevel will be set at the angle abc.
Marking-Gauges.
32.
is
it
H®
make a sharp line. The graduations along length of the beam B,
will
g"
the
;• (
l -
<#%al^r.
are
not to be depended on unless
it
known
is
zero line
is
When
the spur. is
the
that
c {Enlarged)
exactly opposite the zero
frequently the case,
measure from the head
mark and is
it
A
the spur
do not
agree, as
necessary in setting the gauge to to the spur
e.
A
when
set, is
pre-
vented from moving on B, by the screw C. 33.
A
Mortise-Gauge, shown by Fig. 43, has two spurs, a
being fastened to the beam, and b to a brass slide which works in a
groove
spur b
in the
may be
The
beam.
set at
any
dis-
v
, , ;ll
—v
x
"'
"*
K7r
* '
tance from a by the action of the screw
c.
The gauge may,
therefore, be set to line both
sides of a mortise at the
34.
same
time.
Panel-Gauges, Fig. 44, are
for use in
considerable distance from the working-edge.
making
lines at a
BENCH WORK
20
IN
WOOD.
The length of the head A is sufficiently increased to receive good support from the working-edge, which guides it.
Cutting-Gauges, having a long, thin blade in the place
35.
of the usual spur, are in form similar to that shown by Fig. 42.
They
are useful in cutting strips of thin material.
Chalk-Lines are very seldom used in bench work, but
36.
are often convenient in applying such
The cord used
On
strength.
work
to larger structures.
in lining should be as small as
most surfaces blue chalk
is
consistent with
is
more
easily seen than
white.
The
37.
Scriber, as
known
to the trade, takes a variety of
forms, from that of an awl to that of a peculiar short-bladed
A
knife.
well-kept pocket knife of convenient size will
found a good substitute
for
be
any of them.
The Pencil used in lining on board surfaces should be and kept well-pointed by frequent sharpening.
38. soft,
Chisels and Chisel-like Tools. Firmer-Chisels have blades wholly of
39. fitted
Fia.
40. steel.
They
are
is
45
Framing-Chisels have heavy iron blades overlaid with
The handles
ferrules.
and
steel.
with light handles and are intended for hand use only.
are stout
This chisel
driven to
its
is
and are protected
at the
end by
used in heavy mortising and framing,
work by the
mallet.
BENCH TOOLS. Compare
Fig. 45,
21
which shows a firmer-chisel, with Fig. 46,
which shows a framing-chisel. Fix.
The
size
of chisels
46
indicated by the width of the cutting
is
edge, and varies from £" to 1" by sixteenths, and from i£" to
2" by fourths. 41.
A
Corner-Chisel
is
shown by
Fig. 47.
edges are at right angles to each other, and
Its
this
two cutting
form renders
> it
Its
handle
of a corner-chisel 42.
inside angles, as, for example, the corners of
making
useful in
a mortise.
is
is
like that of a framing-chisel.
Gouges have blades
that,
ITi s .
gouges "
;
When the
bevel forming
4S
on the concave
is
when on
size
throughout their length, are
curved in section, as shown by Fig. 48.
the cutting edge
The
indicated by the length of one cutting edge.
side, they are called "inside
the convex side, " outside gouges."
general purposes the outside gouge
is
For
most convenient, and the
carpenter, with his limited facilities for the care of tools, can
more
easily
keep
it
by the length of a the cutting
edge
in order.
The
size of
straight line extending
to the other.
a gouge
is
indicated
from one extremity
of
BENCH WORK
22 Handles
43.
for chisels, gouges,
general classes, light and heavy
hand
cipally for
by a
use,
and gouge
chisel
IN
;
WOOD.
and
similar tools, are of two
the former are intended prin-
and are shown
in
connection with the firmer-
the latter, which are re-enforced at the
;
ferrule that they
may
end
withstand blows from the mallet, are
connection with the framing- chisel and the corner-
illustrated in chisel.
Handles may be shank-fitted,
shown by
or socket-fitted, as
one shown by Fig. 48,
like the
The
Fig. 47.
better class of tools
have socket-fitted handles.
The Drawing-Knife, shown by
44.
wide
chisel,
though
The handles
which
into
is
as
is
Fig. 49,
is
in reality
a
quite different from a chisel in form.
are so attached as to stand in advance of the cut-
ting edge, it,
it
is
drawn
into the work, instead of being
the case with a chisel.
The
drawing-knife
pushed is
very
on narrow surfaces that are to be considerably reduced. The size is indicated by the length of the cutting edge. effective
45.
The Action more or
is
a wedge
to
perform
:
first,
of Cutting less acute.
In action
material,
wood
the cut, the fibers of the split), or the fiber
cutting tool
has two operations
wood and, secondly, may penetrate into the ;
and thus allow the cutting edge
To widen
apart (the rial
it
cutting the fibers of the
widening the cut in order that the tool work.
— Every
Wedges.
to
go on with
its
wood must be pressed
ends crushed, or the mate-
on one side of the wedge must be bent, thus forming a
BENCH TOOLS. shaving.
It is
edge forward result in the
evident that a unit of force tending to drive the
under
will,
conditions of material, always
like
same amount of
entering the material, than able depth, and, hence,
But much
incision.
required to carry the tool forward
due
23
when
it is fair
when
is
is
just
has advanced to a consider-
it
to
less force
the cutting edge
assume that
this difference is
solely to the resistance that the material offers in
opening
make way
for the tool, this resistance increasing as the tool
goes deeper.
The resistance offered to a tool by a bending may be many times greater than that offered edge by the wood fibers.
to
shaving, therefore, to the cutting
An
obtuse-angled wedge
will
cut as easily as a
angled one, but the more obtuse the angle
the
is,
more acutemore abrupt
and since the latter factor more important, as regards the absorption of force, it follows that the more acute the cutting edge is, the more easily must be the turning of the shaving
is
the
it
will
46.
accomplish
Angle
;
work.
its
of Cutting
Wedge
in Chisel
and Gouge.— The
acuteness of the angle cannot be defined in degrees since,
being limited only by the strength of the the duty required of
angle
may be used
it
varies.
steel, it
must vary
as
For example, a more acute
in soft than in hard
wood
;
again, a chisel
handled as shown by Figs. 147 and 148, is not so severely strained as when used in the manner illustrated by Fig. 149. If the
maximum
degree of delicacy were insisted on under
every condition of use, the cutting edge would need to vary with every turn of the chisel, and almost with every shaving cuts. all
these requirements
expressed as follows
metal
it
wood workers reduce principle which may be
This would be impracticable, and
will allow
:
let
to
a single
the cutting edge be as acute as the
without breaking,
experience with a given tool
is
when
fairly
the readiest
the angle suited to a given class of work.
used.
means
A
little
of finding
Carriage makers,
BENCH WORK
24
in hard woods, are in the habit of
who work almost wholly
using what pattern makers,
would
WOOD.
IN
who work
principally in soft woods,
style blunt chisels.
47. Grinding.
— A new
chisel, or
one that has become con-
With the handle of the
siderably dull, must be ground.
Fig.
chisel
SO
hand
on
in the right hand,
and the
the blade near
cutting edge, apply the chisel to the stone,
its
fingers of the left
resting
shown by the dotted outline a, and then raise the hand until the proper angle is reached, a position indicated by the full outline b. See that there is a good supply of Fig. 50, as
right
water, and, as the grinding progresses,
from one side of the stone
Assuming
that the stone
arrow
d.
b,
the tool gradually
good
in fairly
is
should be applied relative to
by a and
move
to the other.
its
the
order,
tool
motion, in the manner shown
Fig. 50, the motion being in the direction of the
If the stone
is
not round or does not run true, there
danger that the cutting edge may dig into it, to the injury of both stone and tool. Under such conditions, it will be best for
is
the operator to
move round
in the position indicated
by
to the other side,
The
c.
chiefly because of two reasons
:
first
first,
and hold the
position
the tool
is
tool
preferable,
may be
held
and, secondly, there is less tendency toward the production of a " wire edge." As the extreme edge becomes
more thin
steadily
;
by grinding,
it
away from the stone, and from the edge to become an extremely delicate edge which must be
springs slightly
allows the chisel at points thin, thus resulting in
still
farther
removed before the tool can be made sharp. remove this wire edge, it frequently breaks off
In the farther
effort to
back than
BENCH TOOLS. is
desired,
and the process of whetting
is
25
With the
prolonged.
chisel held at c (instead of b, the proper position) the direc-
tion of the
motion
relative to the tool aggravates this
of the light edge to spring
The
grinding process
is
reaches the cutting edge
holding the tool to the
away from the
tendency
stone.
complete when the ground surface
—a
condition readily determined by If
light.
it is
still
dull, there will
be a
bright line along the cutting edge.
When
peared, the tool
can be made by grinding,
which,
if
as sharp as
is
persisted
will
in,
it
To whet
48. chisel,
apply
has disap-
The
only result in a wire edge.
action of the grindstone, however,
good cutting edge, and whetted (107 -no).
this line
is
too severe to produce a
must be
the chisel, after being ground,
the
it
to
the oilstone A, Fig. 51, in the position
shown by the dotted outline b, and as it is moved back and
forth along the length
arrows, gradually bring
the angle between cutting edge c
it
it
of the stone, as indicated
to the position
and the stone
comes
is
to
shown by
b'.
be increased
in contact with the stone
;
by the That
is,
until the
this position
can be recognized by the sensation imparted to the hand, and the behavior of the first
thought,
it
oil
with which the stone
may seem
is
lubricated.
At
that
the bevel ab, Fig. 52, which was
produced by the grinding, should be maintained in whetting; to
do
this
but
would require so much
time that one corresponding very nearly to ab, as cd,
Great care
is
is
taken.
necessary on the part of one unskilled to avoid giv-
BENCH WORK
26
WOOD,
IN
ing the tool a rocking motion on the oilstone in,
53
Fi
^
shown by sharper
When
the light, will
sufficiently whetted, the
show a
along the edge,
it
is
dull, grayish
flat
indulged
face,
and
will be no had the form
if it
by the
dotted
cutting edge,
hue.
if
turns a light
an exaggeration of which
shown by
detected by the finger
moved by a',
the
flat
It is necessary,
Fig. 51.
;
may be it
is
re-
a single stroke of the
blade with
shown by
is
This can-
a, Fig. 54.
not always be seen, but
stone, as
outline
held to
If a bright line appears
The whetting
not yet sharp.
wire edge over on the
if this is
Fig. 53,
than
indicated abc.
;
the edge will appear rounded, as
face
on the
however, that
every precaution be taken to prevent the production of a bevel indicated by the dotted line already existing.
To guard
applied to the stone in the
Fig.
c,
54,
and opposite that
against this, the chisel should be
manner
illustrated
by the outline
a,
(111-115).
Fig. 51
A tool must be whetted often enough to keep the edge in good condition it is dull whenever it fails to cut well. When, by frequent whetting, the whetted surface becomes so broad as ;
to require considerable time in the production of the edge,
it
should be reground, and the process just described repeated.
This method of sharpening the chisel to the gouge, drawing-knife,
and
all
will, in
general, apply
similar tools.
Saws. 49.
force if
The it
efficiency of any saw is measured by the amount of absorbs in making a given cut or " kerf." For example,
one saw severs a 4" X 4" timber with half the force required it is evident that the second saw is only one-half
by another,
as efficient as the
first.
Almost every element that enters into
BENCH TOOLS. saw construction has Chief
among them
its
is
effect
the
2?
on the efficiency of the
tool.
thickness of the blade, which, of
course, determines the width of the kerf; for a wide kerf will
require the removal of
more material than a narrow one, and must bear some relation to the
the force absorbed in each case
amount of material removed. In recognition of this fact, the people of some eastern countries use saws designed to cut when drawn towards the operator, a method of handling that
— too great
allows great thinness of blade
to stand the thrust
But the
which our saws are driven into the work. that the Chinese saw, for example,
which
is
Fig.
result
by is
55
represented by Fig. 55, its work with re-
accomplishes
markable ease.
The shape
of such a saw, however, and the
awkward manner of applying
force to
neutralize the advantage gained from
it,
probably more than delicacy, although in
its
the abstract, the thinner the blade the better the saw. 50. but,
The form
of our
own saws
is
not the result of chance,
on the contrary, has been developed
of the conditions
after a careful study
under which they are required
to
Other things being equal, pushing a saw gives better than pulling to
make
it.
Under a
thrusting force,
the blade sufficiently thick
it
work. results
found necessary
is
and strong
to resist
bend-
ing tendencies, but with no surplus material to add unneces-
In view of these facts the outline of the blade
sary weight.
tapered, as
shown by
Fig. 56.
handle than at the point.
To
The blade
is
assist in giving
Fig.
the kerf,
ence
it
is
it
is
accomplished
clearance in
57
tapered from the teeth to the back.
in thickness
is
thicker also at the
This
differ-
in the process of manufacture,
BENCH WORK
28
IN
WOOD.
by grinding the rough blade after it has been hardened. Imperfections left by the hardening or the grinding process, may be detected in the finished saw by bending the blade, as shown
by
If
Fig. 57.
will
uniformly ground and hardened, the curve
it is
be regular as shown
;
if it is
thick in spots, or
if it
varies in
hardness, the curve will be uneven, as indicated by the dotted line.
Set.
51.
edge
— The thinning of the blade most
will not, in
pressing against the saw. are bent
make
— one
to
back from the cutting
cases, prevent the sides of the kerf
one
To meet
side, the
this difficulty, the
next to the other side
from
saw teeth
— so
as to
the width of the kerf greater than the thickness of the
The amount
blade.
of such bending, or " set," as well as
its
uniformity, can readily be seen by holding the saw to the light
with the back of the blade next the eye
shown by
Fig.ss
^
^
it
will
then appear as
In very hard material the sides of
"
"
;
Fig. 58.
smooth and even, and But if the material is soft and spongy, the fibers spring away from the advancing teeth, and then come back again on the blade after the teeth have passed hence, a large amount of set is required. For most purposes at the bench, however, the set is sufficient when it can be easily and clearly seen. *"
scarcely any set
is
the kerf are
required
left
sometimes even none.
;
;
52. Size of
Saw
should begin to cut ting until
it
Teeth.
when
it
— For
proper action, each tooth
enters the work,
and continue
each tooth must contain the material removed by city of the
cut-
leaves the kerf, and, since the space in front of it,
the capa-
space must be increased in those saws which are
required to work through a considerable depth of material.
two-handed cross-cutting-saw
ifor
logs, therefore,
A
has the teeth
widely placed, thus making the intervals large.
In panel-saws, such as are used at the bench, except in spe-
BENCH TOOLS. the space
cial cases,
When
tooth.
is
same
of the
29
size
and form with the
the spaces are large, the teeth must be large,
and, since the size of the spaces has a direct relation to the
amount of material removed, it may be said the teeth depends on the size of the material is
The
size
of saw teeth
Thus
an inch.
one point
another
to
expressed by the number contained
is
" 6 teeth " is
^
means
that the distance from
".
Ripping-Saws and Cross-cutting-Saws.
53.
one that
is
used
— A ripping-saw
in cutting with the grain of the
Across-cutting-saw
line ab, Fig. 59. is
which the saw
to work.
in
is
that the size of in
wood, as on the
Fig.
59
intended for use at right angles to
the grain, as indicated by cd, Fig.
An
59.
shown by
wood be
oblique kerf, such ef,
Fig.
59,
may
latter.
may make knot
is
l/^f*
is
in soft
d
cut with the ripping-saw, which will
the cross-cutting, but the
by the
as
it
A
work
will
work
faster than
be more smoothly done
large knot in the course of the ripping-saw
best to substitute the cross-cutting-saw until the
passed through, after which the ripping-saw
used again.
A
may be
cross-cutting-saw for the bench should have
Fig.GO
Sec.
A B.
ELEVATION.
a 22" or 24" blade with
7^-
ping-saw should have a 24
" or
or 8 teeth to the inch;
26 " blade, with 6 or
a
rip-
6^- teeth.
BENCH WORK
SO
IN
WOOD.
—
The Teeth of Ripping-Saws. Fig. 60 shows a plan, and section of three teeth as they are usually made a ripping-saw. The following paragraphs present a consid-
54.
elevation, for
eration of the action of an individual tooth. All
wood
is
fibrous,
and any
along the length of the at
tool
fibers, as the
which
is
saw kerf
to
produce a cut
ab, Fig. 59, must,
each period of action, take something from the ends of such
61
Fig.
BENCH TOOLS. be at least as acute
as
is
3
I
indicated by the dotted line a
would seem that the former might be improved by bringing it more nearly to the outline of the latter. Sup-
and
it
pose
be attempted, and that the face of the tooth
this
dicated by the line a
change must
Fig.
eb,
it,
ened, the space between
make
it
eb"
accepted, and the tooth
weakened), there
the tooth
and the next
if
is
if
the advancing face
Again,
to
or in changing the line
In other words,
to a position cd[.
is
still
made
not
Having no spaces, there can be no
tooth.
quently the attempted change
is
be reduced. acute, the line
smaller (that it
is,
and the next
teeth,
impossible.
cd
not weak-
is
will
more
be no space between
will
in-
Such
cb\
to
removing material from the
either in
result
and thereby weakening
tooth,
be changed
60,
and conse-
It will
thus be
seen that the angle of the advancing face of the ripping-saw tooth cannot, unless is
shown by
The form the outline
is
it
weakened, be much more acute than
60 and Fig. 61.
Fig.
may be
of the tooth
shown by
Fig. 63,
wholly changed, however, to
and some advantage may thus
be gained in respect of the cutting angle while
suitable
for
;
but such a tooth,
machine-saws of considerable
size,
is
too
complicated for small saws.
Nothing remains, then,
means of improving
as a possible
the
cutting edge of the saw tooth, except a modification of the
angle bed, Fig. 60.
If
it
could be shown that there
needed
of strength in the tooth, above what
is
work, the angle might be changed to
b'ed, or
to
is
an excess
perform
its
even to b"ed, and
Moreseem unreasonable to attempt such a evident that the cutting wedge of the chisel
the value of the tooth as a cutting tool be increased. over,
it
does not at
change, for
it
is
first
(which we have regarded as the typical cutting tool), while
much more be entirely
A
more
acute than the angle bed,
is
yet strong
enough
to
satisfactory.
careful
comparison of the saw and
chisel,
however,
BENCH WORK
32
discloses the following facts
than a chisel in order that
weaker
softer, is therefore
of the saw tooth
made, and,
tage
and,
tion
;
it
lieved
is
its
a
filed,
and being
secondly, the width
;
chisel
a disadvan-
at
is
it
the
operator's
one cutting edge, and
likely to receive too
while
;
respect also,
using
in
thirdly,
and
set
in its substance
this
given entirely to
is
time
in
a saw tooth must be softer
may be
it
than half the width of the narrowest
less
is
chisel
first,
:
WOOD.
IN
much
strain,
is
it
at
atten-
any
at
if
once
re-
each saw tooth, on the contrary, forms but a
small part of a tool that receives
orous handling while
it
is
little
and much
attention
vig-
being driven through straight grain,
crooked grain, or hard knots, as the case may be. consideration of these points,
it
From
a
seems clear that the cutting-
angle of a saw tooth must be less acute than that of a chisel.
But the degree of acuteness can be determined only by Fig. 60
the
most practicable
workers do to dcb\ as
similar to
and,
when
55. is
use.
shows the form which years of experience have proved for general
work, and while some bench-
their saws " under,"
file
producing a tooth similar
many more go to the other extreme and use a tooth The typical form given is easily kept in order, dcf. in that condition, will cut freely
The Teeth
of
Cross-cutting-Saws.
used directly across the grain, the
Fi g
.
and
—
well.
If a
ripping-saw
fibers of the material will
be torn from each
64
other without being
properly cut
saw that cut."
by r
/.Sec.
EF
;
hence
necessity for a
the
its
will " cross-
Fig. 64
shows
three views a
representative
form
of tooth for this saw. It will
be seen by the figure that the tooth terminates in a
trian-
BENCH TOOLS. gular point
;
and
also, that while the point
side of the blade, the next,
thus throughout
33
a', is
length, the points of
its
is
formed on one
show two
any two adjacent teeth
This arrangement makes
being on opposite sides of the blade. the end view of the blade
a
formed on the opposite side
parallel lines of points,
and
between them a triangular depression, which, when exaggerated by the "set," section
AB,
will
appear as shown by Fig.
Fig. 64.
In action, the points a and score the work, the teeth the latter,
and the
a',
friction
65
Fig. 65,
between
and the cut fibers breaks up and they are carried off by
the saw.
Assuming
that
is
it
a matter of convenience to have these
teeth, as well as those of the ripping-saw, equal to the space
between any two of them, there are three questions which may be considered concerning their proportions. First, what shall be the inclination of the advancing edge or " face " of the
by the line ab compared with the line bd, 64? Holly, in his little work on "The Art of Saw-Filing," shows the similarity of action between the advancing edge ab tooth, as represented Fig.
and the edge of a pocket knife when made grain,
and
asserts that a knife with
dicular to the surface lent to
bd)
to carry
it
will
make
upon which
its it
a rougher cut,
to cut across the
cutting edge perpen-
acts (a position equiva-
and require more
forward at a given depth, than
in a position similar to that of the line ab.
force
when it is inclined The result obtained
from such an experiment cannot be regarded as conclusive, because of the great difference in the character of the cutting edges compared.
But,
if
it
is
keen cutting edge behaves more to the work,
it
seems reasonable
edge of a saw tooth inclined.
A
found that the knife with satisfactorily at
to
its
an inclination
conclude that the rougher
will give the best results
when much more
consideration of these points justifies the belief
BENCH WORK
34
WOOD.
IN
60 degrees with the work, that
that an angle of
passing through the points a
show
practice goes to
'
and
a, is
is,
with a line
great,
and
all
formed not only do very
that teeth so
smooth work, but cut with ease and
none too
rapidity.
Secondly, what shall be the angle of the advancing face of the tooth, as represented
by
and
lines e'e
Sec.
ef,
EF,
Since this angle forms the cutting wedge of the tooth,
be as acute as
is
that this angle should
used.
wood than
in soft,
it
follows
be varied with the material in which
For general work
it
may correspond
64?
should
Greater strength
consistent with strength.
being required for action in hard
Fig. it
it is
to the angle e'ef.
Thirdly, what shall be the acuteness of the point as indicated
by the angle
iaj,
Sec.
AB,
obtuse, as iak, for hard
acute, the scoring will be
tween the scores to pass
down
will
into
Fis.66
to
wood than
cause additional strength
This, also,
Fig. 64 ?
by the character of the material is
be
cut.
for soft
It
is
determined
should be more
wood, not only be-
required, but also because,
done so
if
easily that the fibers
too
be-
not break out, and the saw, being unable
new work,
will
slide
along on the
Fi
old.
BENCH TOOLS. cutting-saw, except that
the
line
brought forward as indicated by
when used with the They are, however,
35 advancing face
of the
is
increase their
bkl, Fig. 64, to
efficiency grain.
much finer, there being as many as sixteen inch.
usually
the
to
»
ft
^^^^^
L™*X
This saw cuts slowly as
compared with a panel-saw, but may be used work.
It is
used to cut
The bur
of the wood. a sufficient
any direction
in
by the
left
file
in very delicate
relative to the grain
after sharpening,
forms
set.
The blade A,
Fig. 68,
thrust necessary to drive
by an iron "back," B.
in itself too thin to withstand the
is it
into the work,
and
is
strengthened
This, being thicker than the blade, will
not allow the saw to penetrate beyond a depth represented by
For
the distance C.
this
reason the blade
is
uniform
in
width
instead of tapering.
57.
The Compass-Saw, shown by
sawing in curved Fiff.
lines.
GO
Its
blade
Fig. 69,
is
intended for
extremely thick, and the
is
teeth are given an enor-
mous amount of sections Fig. 69. Sec.
AB
{Enlarged)
which
it
AB
set.
and
See
CD,
If the curve in to
is
be used
is
very small, only a short portion
of
the
blade's
length next the point can
be used. of longer radius, a greater length of blade
With a curve
may be brought
action. ;.
Its teeth are
70,
of the form shown by Fig.
having the square face of the ripping-
saw, and the point of the cross-cutting-saw.
dm^i
Wp
ro
into
BENCH WORK
36 They
IN
WOOD.
are thus adapted for use in any direction relative to the
grain of the wood.
Appliances for Saw Filing and Setting.
A
58.
Fig. 71.
"
Saw
Triangular
A
"slim" saw
file
File
" *
is
of the form
shown by
represented by Fig. 72;
is
Fig. 71
Fig. 73
Fig.
74
REGULAR.
two inches longer than a "regular" saw
same
cross-section.
Fig. 73,
A
" double ender "
and a cross-section of
all
saw
file is
files,
of the
shown by on an en-
larged scale, by Fig. 74. 59.
The
it
Fig.
Saw
Sets.
—
Fig. 75
tooth to be bent 1
is
shows a simple form of
set.
placed on the surface A, with
Frequently called " three-square saw
file.
is
72
BENCH TOOLS. the adjacent teeth in contact with B,
blade
is
allowed to
on the screw C. from
Thus placed, the
B.
rest
A
blow
D
hammer on
a
37
bends or "sets" the tooth,
D to
and a spring returns 1
The amount of set is regulated by the position of the screw C, and is greater, the position shown.
the lower is
C is fixed.
C
If
raised to coincide with
AE,
the dotted line
tooth will not be
the
B,
set.
the tooth to which the set 60.
Swedge and,
small ones ing, they
D
is
Fig.
76
on
generally speak-
do not concern the
bench-worker.
1
on lame °
occasionally, ;
can be adjusted to the depth on
to take effect.
Sets for Ripping-Saws, illustrated by Fig. 76,
are in general use
saws
B is
The
set
V
:
is
not well shown in the engraving.
tooth at a time, the end
X
is
wedge-shaped.
Since
it
must
act
on only one
BENCH WORK
38
IN
WOOD.
driven against the edge of the tooth, as shown by Fig. 77 ; by is forced back, as
using one opening the center of the tooth at
H;
and by use of the other opening the points are spread, at G. A tooth thus set is more
completing the work, as perfect in
its
action than
when
bent, since
it
cuts the
full
width
of the kerf. 61.
Saw Clamps
are convenient for holding the saw during
Fig.
the filing process.
clamps similar
78
Carpenters frequently
to that represented
by
make
for
themselves
It consists
Fig. 78.
of
by two screws two pieces of hard wood may be clamp which the of means (one near each end), by joined face to face
Tri s .ro
fastened rigidly to the blade of the saw.
ened
in
It
may
the
vise
then be or
the knee while the saw filed.
A much
the saw clamp
fast-
on
held
being
is
better device
shown by
is
Fig.
79, which, while fastened to the
bench, so holds the saw that
may be
direction,
workman light.
it
turned in almost any thus
enabling
the
to obtain a favorable
BENCH TOOLS.
To 62. it
This
Fig. 80.
and
File and Set a Saw.
Top-Jointing. — With
by running a
file
is
vex. facet
The
the saw
clamped teeth up,
joint
along the tops of the teeth, as shown by
done
to bring
also to maintain the
line of the teeth,
39
all
same
the teeth to the
height,
form of the saw, which, along the
in s so
should be slightly con-
.
jointing should leave a small
on each
tooth,
which
be rec-
will
tangular in a ripping-saw and triangular in a cross- cutting-saw.
63.
Setting.
PLAN.
— Beginning
at
one end, bend outward every
second tooth, then turn the saw and bend the remaining teeth toward the opposite side of the blade. ping-saw,
if
the swedge set
is
In the case of the rip-
used, the setting should be
done
before jointing. 64.
—
Filing.
of great importance that the saw be
It is
properly supported during the operation of
amount of
noise shows that the blade
or that the
file is
file is
movement. filing
not going on as
being injured.
sure be very light.
be done in
is
Carry
Never take this
it
If the
across the
;
it
file will
new,
is
by plan,
suffer
movement should be
Fig. 81,
shown by the elevation
in the
the form of the teeth
must be turned either by the arrow, In
filing
is
to
might, and the pres-
let
beyond
and the
outline
of the teeth maintained by an even contact, as
if
it
work with a
exactly perpendicular to the plane of the blade, as indicated
same
unusual
also a sure
is
fast as
slow, steady
quick strokes, as but
short,
way, and the
a ripping-saw, the
file
An
filing.
not properly clamped,
not being properly handled
indication that the filing that the
is
figure.
be changed, the
little
will
repair.
In
^ FiL £j?
lijfej^^i eleva ™n.
But
fc
file
in the direction indicated
PLAN
*
Fig. 81, or in the opposite direction.
a cross-cutting-saw, the angle between the
file
and
BENCH WORK
4o
IN
WOOD.
the blade must be varied in accordance with the following considerations
the outline of the
first,
:
manner
or changed in the
the ripping-saw (e'ef,
Fig. 64)
teeth
may be
preserved
just described in connection with
secondly, the angle of the advancing face
;
is
determined by the inclination of the
file
the blade, as shown
to
by the plan, Fig. 82 thirdly, the angle of the
point
Fig.
82
Fig.
(iaj,
64)
determined by the nation of the
end
elevation, Fig. 82.
The form END ELEVATION.
to the
file
shown by the
blade, as
SIDE ELEVATION.
is
incli-
of the
been
having
teeth
decided
upon from principles already given, it may be produced without difficulty by attending to the foregoing directions. In
filing
any of the teeth herein discussed, the
should
file
always be in gentle contact with the face of one tooth, as Fig. 81, while
next one
being
a,
filed.
most of the cutting
files
when
is
the tooth that
This tooth should be one which, by
its set,
is
turned,
is
bends
Beginning at one end of the blade,
every second tooth until the opposite end
the blade
b,
done on the back of the
which, as usually considered,
away from the operator. he
is
reached,
is
and the remaining teeth
filed
from
the other side.
No
saw, even though the teeth are not bent, should be filed
wholly from one side, for the and, since this increases the
on both
The
turns a slight edge, or bur
file
set, it
should be evenly distributed
sides of the blade. filing
on each tooth should continue
produced by the
jointing disappears.
plished, a single stroke will
than the others.
To
avoid
make
until
After this
the facet is
the tooth receiving
this, it will
accomit
lower
be found best to leave
BENCH TOOLS. the teeth filed from the
side a
first
41
little
dull, for, in filing the
intermediate teeth after the saw has been turned, the advancing faces of the others (the teeth
first filed)
are
After every tooth has been passed over,
somewhat reduced.
if dull
points are
be seen, they may be sharpened from either side as
to
proportions the teeth,
may
Regularity in the size and form of
dictate.
and a
similarity of
appearance when viewed from
either side of the blade, are the tests of
Side- Jointing.
65. ing
is
finished, the
will cut
is
more smoothly
of the
sides
jointed,
— Usually, when
saw
the dotted lines Side-jointing
of either a
file
A
;
is
good workmanship. the
fil-
ready for use, but
if it is
it
jointed on the
In Fig. 83,
teeth.
the surfaces
still
their
B
is
side-
produced agreeing with not side-jointed.
may be accomplished by or an oilstone.
It
is
use
always
necessary after a swedge set has been used.
Planes and Plane- like Tools. 66.
The
The plan and the section, Fig. 84, show a smooth-plane. when of wood, is usually of beech. In it is an
stock a,
opening, or " throat," iron c
;
this is
b,
which receives the
held in place by the wedge
Fig.
84
d.
The lower part of the opening is called the mouth and, as shown by the figure, the shav;
ing passes into the mouth, and out through
section
a b.
The bottom of the plane, which rests upon the called its " face." The iron usually stands at an angle
the throat.
work,
is
of 45 degrees with the face. The bench-worker's set of planes comprises a smooth-plane, Fig. 85, which is about 8" in length; a jack-plane, Fig. 86, which is from 12" to 14" in length; a fore-plane, Fig. 87, from 22" to 26" in length ; and a jointer, from 28" to 30" in length.
BENCH WORK
42
IN
WOOD.
Similar purposes are served by the jointer and the fore-plane, the former being unnecessary except for large surfaces that are to be planed with accuracy.
85
Fig.
Fig. ETiar.
The Length
67.
86
87
of the Plane-Stock determines, in a measure,
Thus, a smooth-plane,
the straightness of the work.
Fig. 88
if
used on
an uneven surface, as
shown by
will,
Fig. 88, rise
over elevated portions and settle in hollows, taking its
shaving without interruption, and
producing no great change
in the outline of the surface, while
a
Fig> so
fore-plane
or
jointer
similarly applied will, as
shown
by Fig. 89, cut
only on the higher parts,
and by so doing, produce an even
The
stock of a smooth-plane
a surface
may be smoothed
straightening
The The
it
surface.
made
short so that, by
its
use,
without incurring the necessity of
it.
fore-plane will
not until
is
has
jack-plane
smooth
as well as the smooth-plane, but
straightened the surface.
first
is
used for cutting heavy shavings, and
its
length bears no relation to the character of the work expected
of
it,
and
but
is
such as
68.
A
"Plane-Iron" 1
enable the
same way
for a
Its cutting
in part with steel.
the
will
workman
to grasp
it
easily
firmly.
wooden plane edge
as that of a chisel.
1
Known
is
is
of iron overlaid
maintained in precisely
See 47 and 48.
also as " plane-bit.
The
angle
BENCH TOOLS. of the cutting wedge, however, for
may be more 69. is
The
all
43 except the jack-plane
acute.
outline of the cutting edge, unlike that of the chisel,
never straight, being for the jack-plane slightly curved, as
Fig.
oo
shown by Fig. 90, and for the smooth-plane and fore-plane (also for the jointer) of the form shown by Fig. 91. Being used for
F> is .
91
heavy work and frequently removing shavings as thick as one-sixteenth of an inch,
the jack-plane, straight,
if
its
cutting edge were
would produce
in
the
work
at
each stroke a rectangular channel from
which the shaving must be torn as well
as cut.
Such
a shaving would be likely to stick fast in the throat
of the plane, or, under most favorable conditions,
would require a large amount of force
A
90, however, in the
for
its
removal.
shaving removed by the iron represented by Fig. is
not rectangular in section, but thick
middle, tapering gradually to nothing
This form of iron
is
amount of material
at
the
edges.
best adapted to the removal of a large
at a stroke, but
it
leaves a succession of
grooves upon the work which must be smoothed off by another plane.
70.
The form
of the cutting iron in the smooth-plane and
the fore-plane, as
shown by
greater portion of
its
The
Fig. 91,
is
straight throughout the
width, and slightly rounded at the corners.
objections urged against the use of such an iron as this in
the jack-plane,
do not apply
to
its
use in the smooth-plane or
the fore-plane, because the jack-plane, to
fulfil its office, must remove a heavy shaving ; the smooth-plane or the fore-plane, unless the surface upon which it acts is very much narrower
than the width of the plane,
is required to remove a shaving whose thickness rarely exceeds that of a sheet of paper. The
BENCH WORK
44
IN
WOOD.
groove caused by the removal of so delicate a shaving, ficiently
rounded corners of the
amount of material
wood
suf-
iron.
71. If a rough board
able
is
blended with the general surface of the work, by the
to size,
to
is is
be made smooth, or
to be
removed
a consider-
if
to bring a piece of
most of the surplus stock should be taken
off
by
the jack-plane, after which the smooth-plane should be used to give the surface desired.
If the finished surface
is
to
be straight
as well as smooth, the fore-plane should follow the jack-plane. It is
never necessary to follow the jack-plane with both the
smooth-plane and the fore-plane. 72.
The Cap.
—A
supplementary
iron, or
c,
Fig.
"cap," shown by
92,
is
fastened
most plane-irons. is
well
illustrated
Its
to
use
by the
two sections, Figs. 93 and 94.
the grain of the
grain
becomes
wood
is
favorable,
obstinate, as at
b,
The
iron
single
do smooth work as shown at a.
When
the shaving, by running
the iron, acquires a leverage which causes
it
will
as long as
to split in
the
up on
advance
BENCH TOOLS.
45
of the cutting edge, below the reach of which
a surface extremely rough.
The
the shaving as soon as possible after
prevent a gain of leverage on
its
it
it is
breaks, leaving
cap
is
to break
cut, Fig. 94,
and thus
office of the
part.
The iron,
distance at which the cap is set from the edge of the must vary with the thickness of the shaving taken. For a
smooth-plane or a fore-plane, a thirty-second of an inch
is
fre-
quently not too close, while for a jack-plane an eighth of an
inch
may not be
too great a distance.
A
cutting iron
and cap together are frequently spoken of
as
a " double iron."
73. in the
Narrowness
Mouth
of
in a plane
production of smooth surfaces.
tion of the stock in advance of the iron, ing, the shaving,
is
If,
having nothing to hold
the chief element
in Fig. 94, that por-
marked it
c,
were want-
down, would rarely
be broken, notwithstanding the presence of the cap.
mouth would produce a
similar effect.
ever other conditions there
may
A
wide
This being true, what-
be, the wider the
mouth
is,
the less frequently the shaving will be broken and, in obstinate grain, the
rougher
will
be the work.
BENCH WORK
46
To Adjust the Iron.
74.
may be
a heavier cut
by the arrow
e,
IN
— To
taken, strike
WOOD.
set the iron deeper, so that it
a light blow, as indicated
If a lighter cut
Fig. 84.
is
required, strike the
When the iron is in the stock as indicated by the arrow f. will tighten the wedge. light To remove position, a blow right and wedge, turn the plane over so
the iron
that the face
is
uppermost, grasp the iron and wedge with the right hand, hold
end of the plane between the thumb and finger of the / upon the surface of the bench.
the back left,
A
and
strike the stock at
blow
single
Never
is
usually sufficient.
strike the plane while
support that everything
;
is
firm.
but, if this
is
it is
resting
on the bench or any
should be held in the hand clear of
It
not convenient, one end
may
rest
on
the knee.
To way
set the iron in a
that,
finger
may extend
allowing
keep
it
its
plane, hold the stock in such a
across the mouth.
cutting edge to rest
and by a
light
until its projection
on the
Put the iron in place, forefinger,
Insert the wedge, push
from projecting.
the thumb,
down
wooden
while the face rests on the hand, the end of the fore-
on the wedge
it
down
with
blow with the hammer drive the iron
beyond the
level of the face
to the thickness of the shaving that the plane
gle tap
which should
will
is
to take
is
equal
;
a sin-
then tighten the iron in place.
The
distance that the iron projects, can easily be determined by sighting along the face of the plane.
The wedge must not be
driven too hard, for a plane
may be
by a hard- driven wedge as to make it incapable of doing good work. The iron will be held in place even when the wedge is so loose that it may be drawn out with the fingers. so distorted
Notwithstanding the fact that wooden plane-stocks are
from material will
little
affected
warp enough, especially when nearly new,
considerably out of a true plane.
plane
fails
to
do good work,
it
made
by atmospheric influences, they to bring the face
When, from
must be jointed.
this cause, the
BENCH TOOLS. 75.
To Joint a Plane, fasten it front end to the right. The
47
in a vise with the face
and the
up
iron should be in place, the
back within the mouth,
cutting edge well
and the wedge driven
as for work.
It is
e
now
|a
i;-
, {
necessary to determine whether the plane
be jointed
to
is
Ap-
twisted or not (97).
v
ply two parallel strips, or "winding-sticks,"
(the longer legs of two framing-squares will
answer), one across each end of the plane, indicated
as
by
Fig.
making
After
95.
M
sure that they are parallel, sight across one
As the eye
to the other.
one farther away
is
is
lowered,
lost sight
same time, the plane
is
of
all
;
but, if
end of the straight-edge that
one
farther
is
from the eye, disappears before
other
its
end, as in the elevation, Fig. 95, b,
the
"out of wind," and
needs only to be straightened
corners a and
if
at the
it
evident that the two
is
diagonally opposite, are high, and
be taken from them than from the other corners. understanding, the fore-plane or the jointer the plane
until
is
jointed, that
is,
may be
the
until
more must With this
face
applied a
is
true
plane.
During the planing process, frequent
make
with the parallel strips, to are
being brought
down
sure
properly.
tests
must be made
that the
In the
high corners
early stages
of
may be used occasionally to keep as nearly as may be at right angles to one side, straightness of the face may be determined either
the work, the try-square the face
and the
by sighting or by use of the framing-square edge.
A
between
true it
face having
and the two
sides
should be
chamfers, inasmuch as the sharp edges, likely to splinter off.
as
a
straight-
been produced, the sharp angles
if
changed
to
slight
not removed, are
BENCH WORK
48
A
drops
few
planed surface,
of will
lubricating
WOOD.
IN oil
rubbed
prevent wear and
on the newly-
keep shavings from
sticking.
Wooden bench
planes have had their day, and are going out
of use.
76.
Iron Bench Planes possess the general characteristics of the
OG
jpj
to
wooden ones, but are superior them in several respects. They
are always perfectly true and, therefore, neve'r
require jointing.
The
cutting "iron," which, in this case, is
not of iron at
wooden
planes,
greater thinness
which
it
is
but of
all,
and is
steel, is
much
thinner than that in
more readily sharpened. Its made possible by the thorough manner in is,
supported.
therefore,
It
may be
set
and accurately adjusted
in a very short time.
The arrangement
of parts in Bailey's iron planes
may be
understood by reference to Fig. 96, which represents a jackThe " wedge " A is of iron of the form shown it plane. ;
E through an enlargement of a short slot, and allowing E to take effect. By a movement of the
admits the screw
drops down,
clamp B, the wedge
A
is
made
to press
upon the
cutting edge, while the clamp presses against
screw
E
is
never moved.
The
cutting iron
it
is
iron near at F.
its
The
adjusted for
depth of cut by the action of the thumb-screw D, which, when turned in one direction, moves the iron downward, and when
motion is reversed moves it upward. Thus a single movement of B releases the wedge and iron, furnishes and a reverse movement secures them again, while a ready and positive means for adjusting the cutting edge with a degree of delicacy which it is impossible to attain in wooden These planes, all having the same adjustments, are planes. its
D
made
in every size.
BENCH TOOLS.
Wood and
Planes of
77.
may be
made up
had,
ments mounted
49
Iron Combined
of the Bailey move-
in a suitable frame, to
which
97 shows a Stanley combination smooth-plane. a wooden face
A
78.
Fig.
fastened.
is
Circular-Plane has a thin steel face, straight free,
Fig.
08
but capable of having
down
its
when
ends thrust
drawn up, thus making the
or
and adapting it work on an outside or an inside curve. - Fig. 98 shows a Bailey's adjustable cirface concave or convex, to
'
^ ^^7:-:-^^^ -<[^" ,
—
cular-plane.
Block-Planes are small, and are intended for use chiefly
79.
on end
grain.
They
generally have a single inverted iron,
which turns the shaving on the bevel of on
instead
the
face
of
the
Fig.
iron.
00
^^/^^-^^^
A
They have many different forms, from among which Fig. 99 has been selected as
a type.
or wide as
In this plane the throat is
desired
;
may be made narrow
the adjustment
is
controlled by the
screw A. 80.
Spokeshaves have the action
of planes, but are not usually classi-
shown by tion
it
A
them.
fied with
Fig. 100.
will
simple form
By
be seen that
it
has almost
no guiding surface corresponding the face
adapts
to
plane.
work of
is
to
feature
The
cutting
and the iron is of the stock, as shown
set in the face of the plane obliquely,
wide enough to extend beyond the sides
This
irregular outline.
Rabbeting-Planes have narrow stocks.
81.
edge
it
of a
is
the cross-sec-
BENCH WORK
5o by
Fig.
1
IN
WOOD.
Rabbeting-planes are
01.
interior angles.
Fig. lOl
The oblique
&.
designed for use
in
position of the iron produces a
shearing cut which promotes smoothness in action.
The shaving
of the rabbeting-plane
instead of passing through the stock
turned in such a way as to be
charged from one side
;
is
dis-
an arrange-
ment common to matching-planes, beading-planes, moldingplanes, and plows (82, 83, 84, and 85).
Fig. 102
A
B
JUI
BENCH TOOLS.
51
Hollow and Round are terms applied to such planes shown by A and B, Fig. 103. They are used, as their forms suggest, in producing hollows and in rounding projecting edges. Their size is indicated by a number, or by the width of 83.
as are
the cutting edge.
Beading-Planes are used
84.
they
may be
beads
in
forming beads (220), and
form one or two Ki s 104 For beading on the edge of work,
single or double, that
at a time.
is,
.
they are provided with a fence, A, Fig. 104. use away from the edge, they are
made
to
n
For
form three
or more beads at the same time, and have
nno
guide, in which case they are
reeding- planes, Fig. 105.
The
known first
as
three
beads are made with the plane guided by a straight-
edge temporarily fastened to the surface of the work the remainder are formed
made work
by using those
as a guide, the plane being at the rate
moved
•
already-
into
new
Other
of only one bead at a time.
more complicated than those described, are conThe size of a the same principle as a plow. beading-plane is indicated by the width of the bead it will form.
beading-planes, structed on
much
Plows
85.
are used in
of any width, depth, and
The width
the material.
ordinarily determined
the iron used.
A
106.
A
slots or "
plows "
distance from the working-edge of
of the cut
is
by the width of
set of irons is sup-
plied with the tool, which Fig.
making rectangular
is
shown by
plow wider than the
widest iron can, of course, be
made
by going over the work a second time.
The depth a
little
of the cut
is
regulated by
shoe (not shown), which
screw A.
When
is
raised or lowered
this is adjusted, the tool
by the
can be used
until
BENCH WORK
52
IN
WOOD.
comes
the lower surface of the shoe
in contact with the face
Care should be
of the work, after which the cutting ceases.
taken that the
depth
full
The
length of the work.
working-edge
C
by nuts
is
is
reached at
all
points along the
distance between the groove and the
regulated by the fence B, which
acting on the screws
When
D.
is
adjusted
ready for use, the
fence should be parallel to the narrow iron face-piece E. 86.
Combination Planes which may be used
plow, beading-plane, rabbeting-plane,
market, and
many
Scrapers.
87.
irig.
of
them
etc.,
in place of the
are found
on the
are serviceable tools.
— Hand-scrapers
are
made
of saw-plate
— ma-
terial of about the thickness of a panel-
107
saw blade, and having the same degree of
They
hardness.
are usually rectangular,
and about 4" X 5", but may be of almost any size and shape. The cutting edge is most easily formed by the production of at right angles
a surface
as indicated
two cutting angles, cef and acute cutting edge Fig. 108 is little
is
When
;
the
sides,
a more
shown by
desired, the form
may be adopted
to
ab, Fig. 107, thus giving X|
but, as a rule, there
gained by the keener cutting edge, and
double the labor
is
required to keep
Scrapers are sharpened by
smooth work edge
dfe.
by
is
to
filing
sharp. If
be done, the roughness of the
may be removed on an
rougher edge
it
or grinding.
will
oilstone, but the
cut faster and, generally, will
be more satisfactory. Fig. 109 Fig. 109 shows a scraper mounted somewhat like a plane. The scraper blade A, by
means of
the two nuts B, B,
from a position inclined to
one perpendicular
may be changed
to the face, as
to the face.
shown,
BENCH TOOLS.
53
Boring Tools. Augers.
88.
—
Fig.
no
shows a double-twist spur auger,
a form generally used by carpenters.
They
are
made
in sizes varying
Fig.
J" to 4" (in diameter), but are not much used below 1". The spur A, Fig.
in,
is
in the
2C£CCCC=
form of a tapered
screw, which, besides centering the auger in
"feeds "
and the
it
The two
into the work.
lips C,
HO
from
C cut and remove
nibs
its
B,
motion, draws or
B score
the work,
the shavings, which are carried
Fig. Ill
to the surface
Fig.
by the screw-like action of the body of the
be seen, has but a single nib B, and a single cutting
The
tool.
112 shows part of a single-twist auger which, as will
cuttings are thrown into the center of the hole,
lip
C.
and de-
Fig. 112
livered easily
by
this auger,
to the double-twist,
and, in this respect,
it
is
superior
which crowds the cuttings to the outside
of the hole, where they are likely to the tool and the work.
become jammed between
This characteristic of the single-twist
auger particularly adapts it
to the boring of
holes.
of
this
" Ship augers kind,
deep ' '
Fi~. 113
are
and have
handles like the one shown by Fig. 113.
This form of handle
BENCH WORK
54
WOOD.
IN
has the advantage of allowing the use of both hands, without the
no.
interruption experienced in using the one illustrated by Fig.
Augers are seldom required by the bench-worker, but are presented here because of their relation to other boring 89.
— The
Auger-Bits.
auger-bit most in use
It is sold in sets
Fig. 114.
by
sixteenths,
Each
to 1".
by a small
Thus the
figure 9
from \ n
bit is
marked
figure
on the
shank, which
of sixteenths.
shown by
is
of thirteen bits each, varying in size
size in the scale
tools.
indicates
its
to be inter-
is
preted as Ty. 90.
Augers and auger-bits are sharpened by
The
filing.
in
and 112, which is usually the first part If to become dull, should be filed wholly from the inside. filed on the outside, the diameter of the cut it makes will be scoring nib B, Figs,
smaller than that of the
body of
the
The
bit.
should be sharpened from the lower side, the to preserve the original angle.
whenever the
file
With the spur
tool refuses to " feed,"
it
is
cutting lip
C
being inclined
in
good
order,
clear that the bit
needs sharpening somewhere. 91.
Center-Bits are convenient for boring holes
of large
diameter in delicate material, such as would be likely to
under the action of an auger-bit.
^^p^ A ~~~P\
^^
will
Fig. 115
it.
the proposed hole,
The
is
bit
in the
triangular in section. bit to feed
accordance with- the degree of pres-
point, or "nib,"
and the cutting
center-bit does not easily
'
This form allows the
sure applied to
it
be seen that the spur A, l
work,
,
split
reference to Fig. 115,
which centers the
rapidly, or very slowly, in
The may
By
work
lip
well in
be sharpened by whetting.
B cuts
C
end
the fibers about
removes the material. grain.
When
dull
it
BENCH TOOLS.
55
Expansive Bits are so constructed
92.
be adjust-
as to
There are
able for holes of any size, within certain limits.
forms
several
use,
in
one of which
without the
This,
shown by
is
Fig.
116.
Fig. 116
movable cutter C, bore
will
a
hole
J" in diameter, the screw A centering
and feeding
into the work,
it
advance of
B
inserted as
shown is
and
is
and a cutting
in
lip
When C
a supplementary action on the part of C,
described, there
C
scoring,
is
in the figure, in addition to the action just
nib, B', scoring,
cutter
B
(not shown) removing the shavings.
its
held in place by the screw
may be moved from
its
The By loosening D, C
cutting edge removing the chips.
D.
or towards the center of the
bit,
or taken
out altogether, and replaced by a cutter of different length.
By
using a short cutter in the place of C, a hole of any diameter
from f" to 2" may be bored, and with the cutter shown, any The range of the bit, therehole from 2" to 3" maybe bored. fore, is
from f"
Small
93.
eter are of
to 3".
—
Bits.
many
Bits for boring holes less than
forms, but by far the
most
^"
in
satisfactory
diamis
the
"quill " bit
Fig.
117'
117.
It
parts
if
it
rial
it
;
enters the
and when
dull
work
can
It will not,
ing.
shown by Fig. has no delicate
rapidly,
easily
;
will
carefully
not
split
handled
the mate-
makes a round, smooth
hole,
be sharpened by whetting or grind-
however, work with the grain.
y
Quill bits as
small as T in diameter are in common use. Gimlet-bits are illustrated by Fig. ti8, which represents one
of the best forms. bits
Most
of this class are too
weak
to render the ser-
Fig. 118
BENCH WORK
$6
IN
WOOD.
and soon become bent or broken. work and are not easily sharpened.
They
vice expected of them, are likely to split the
Bit-Braces.
94.
— The
well-made wooden brace, which
for
a long time ornamented the walls of the cabinet-maker's shop, has disappeared, and the lighter and more
brace
is
used in
its
stead.
To
resented by Fig. 119.
holding
it
shank, put
convenient iron
simple form of iron brace
insert a bit, grasp the sleeve
is
rep-
A
and,
by using the other hand on opened sufficiently to admit the bit reverse the motion of the hand on B, and
firmly, turn the brace out
When
B.
A
the jaws, C, are it
in place,
the bit will be fastened. Fio..
A
ratchet brace
is
shown by
Fig. 120.
Its office is to
turn
making a comhas only a forward and backward movement.
the bit forward while the brace plete revolution,
119
itself,
instead of
As represented by the section AB, the frame c is fastened to the body of the brace of which it becomes a part, d is a spindle which terminates in the socket e, and / is a ratchet-wheel, which is
is
fastened'to d.
a pawl which,
when
On
each side of the ratchet-wheel there
free to
move
in response to the action of
a spring, engages the notches in the ratchet-wheel
pawls thus engaged, the brace
way g,
as the
may be used in
one already described.
one of the pawls
is
But,
/
With the same
precisely the
by turning the
ring
disengaged, and the other acting alone
BENCH TOOLS. will
move
the spindle
direction, the
ratchet-wheel bit
may be
the brace
d
when
only
57
the brace
is
moving
in
one
pawl simply slipping over the notches of the
when
the motion
is
In this way, a
reversed.
movement of By a motion of the bit may be
driven to any depth although each
may be
less
than half of a complete turn.
proper movement of the ring
g,
the
reversed.
Fig.
120
Section
A B.
(Enlarged)
The
ratchet-brace
corners where
The
size
it is
is
useful in boring holes near walls, or in
impossible to turn a
of any brace
by the diameter of the
is
common
indicated by
circle described
its
brace.
" swing," that
by B,
Fig. 119.
is,
The
better class are nickel-plated, and are thereby prevented from
BENCH WORK
58
A
95.
IN
WOOD.
"Universal, Angular, Bit-Stock," such as
sented by Fig. 121,
is,
for
many
purposes,
more
is
repre«
useful than
Fig. 131
The
the ratchet-brace.
brace parts
A
is is
bit is inserted at
such, that,
when
which holds the
clination of
common the
the brace turns the spindle C, the part
bit is also turned,
one part
A, and a
The mechanical arrangement of
applied at C.
to the other.
1
notwithstanding the
Compared
in-
with the ratchet-
brace, this has the advantage of producing a continuous motion
of the
bit.
By
easily as in the
The
its
use a hole
may be bored
in the corner as
middle of a room.
angle of the joint
may be changed from at D.
that
shown
to
one of 180 degrees, by an adjustment
—
A convenient substitute for Automatic Boring Tool. The drill, or bit, A is 122. Fig. a brad-awl is represented by 96.
Fig. 12
Considered as a mechanical movement,
this is
known
as
Hooke's
joint.
BENCH TOOLS.
59
held in a suitable chuck C, at the end of the bar D, which
The
runs in B.
drill
is
brought into contact with the work,
B
down upon and pressure in the direction of the arrow, slides with the drill to revolve. The D, and this movement causes full extent of the movement having been reached, a relaxing of
D
pressure leaves
D free to return
to
its first
position, as shown,
These
rotary motion of A, meanwhile, being reversed.
the
impulses can be imparted to the
work
the
quickly done.
is
indicate the
full
The
drill
with great rapidity, and
dots below the figure, 122,
diameter of the different
drills
which are
fur-
nished with the tool.
Miscellaneous Tools. 97. Winding-Sticks, or "parallel strips," are
wooden
strips
of any convenient length, the edges of which are straight and parallel.
When
applied to a surface, they increase
its
breadth
and by thus giving a better opportunity of comparishow whether the surface is " in wind," or twisted. For
in effect,
son,
an
illustration
98.
by
Hand
Fig. 123.
of their use, see 75.
Screw-Drivers are in form similar to that shown
The
part which
is
to
engage the screw should
have parallel sides, as shown by Fig. 124, and never be wedge
shaped, Fig. 125.
In the latter case,
it
will
be seen that force
applied in an attempt to turn a screw, will have a tendency
toward
A
lifting
the screw- driver from
its
set of three or four screw-drivers,
place.
having blades varying in
BENCH WORK
6o
IN
WOOD.
size to suit different-sized screws, so that a fairly
good
fit
may
always be made, are indispensable to good work where screws are
125
Fig.
much
used.
Brace Screw-Drivers, instead of having
99.
wooden
handles, are provided with shanks for
A
use in a brace. Fig. 126. tion,
The brace
good form
is
shown by mo-
gives a continuous
and
Fig.
1SG
the screw
may
be by its use than with the hand screw-driver. however, in which a brace is useless. set
much more
Hammers.
100.
head
rapidly
A
is
There are many
cases,
— Fig. 127 shows a carpenter's hammer.
The
wholly of
to be injured
The
steel.
face
B
by repeated blows upon the
paratively soft, but the idea prevailing
workmen,
that the
hammer
is
two bodies are brought together
and a
nail,
form.
the softer If the nail
body
hardened so as not nail,
yields,
which
is
com-
among inexperienced
indestructible,
When
its
is
is
a
forcibly, as
false
a
one.
hammer
and a change takes place in it would not
were harder than the hammer,
be injured, but the hammer would show an impression of the nail head.
Careless or ignorant
workmen sometimes
take an
BENCH TOOLS. old
file
The
for a is
file
punch or a
6l
and use a hammer upon
nail-set,
harder than the hammer, and the result
face of the latter
C
The claw withdrawing
is
is
it.
that the
badly scarred.
makes the hammer a very
effective
tool for
nails.
Hammers vary in size from seven to twenty ounces the bench-worker usually employs one weighing from fourteen to ;
sixteen ounces.
101.
The Hatchet
is
a useful tool for bringing large pieces
of material to size roughly, and in
used with accuracy as well as with the hammer,
it
will
skillful
the place of the claw C, Fig. 127.
amounts
to but
little.
is
it
may be
compared
128
As an instrument
clumsy, and the opening
it is
it
be seen that a blade C, Fig. 128, takes
Fig-.
ing nails
hands
When
effect.
d, for
for driv-
withdrawing
In sharpening, the hatchet
is
nails,
ground on
both sides of the blade, and whetted on an oilstone.
—
The difference in effect between a blow hammer and one given by a mallet is so great that, although similar in many respects, the two tools are adapted to A blow from a hard, elastic hammer is widely different uses. 102.
Mallets.
given by a
sharp and decisive, and it
is
received.
must be
local.
its
force
is
absorbed almost as soon as
Comparatively speaking, therefore, If such a
blow
for example, a large part of
its
is
its
effect
received on a chisel handle,
force
is
wasted in affecting the
BENCH WORK
62
IN
WOOD.
handle, a part only being transmitted through the handle to the cutting edge, the only place where
blow from a general in
elastic mallet,
soft, less
its effect.
Much
where
it
is
can be of use. is
A
more
of the force remains for an instant
stored in the mallet, by which ually, allowing
it
on the contrary,
it
given out somewhat grad-
is
time for the impulse to pass beyond the point
The
received.
effect of
two different explosive
As compared with nitroglycerine, powder burns slowly, and, when put into a rifle barrel, gradually develops its force upon the bullet until, when the latter reaches the end of the barrel, it has gained velocity enough But if a charge of nitro-glycerine, to carry it a mile or more. agents will serve as an illustration.
TTig.
139
having a total explosive force no greater than that of the powder, ity
be substituted, the
result will
impulse
—
is
such
that,
The blow of a powder on a unlike
The
is
rapid-
suddenness of the its influ-
destroyed.
mallet on a chisel resembles the action of
bullet.
that
different.
— the
before the bullet can respond to
ence, the breach of the barrel
is
be very
with which nitro-glycerine burns
It is
of the
driven deeper into the
a pushing action, and, in this respect,
hammer. A chisel, therefore, will be work by a blow from a mallet than by from a hammer, while a chisel handle
one of the same force which has withstood blows from a mallet for years, may be shattered in a single hour by use under a hammer.
An
excellent form of mallet
is
shown by
Fig. 129.
BENCH TOOLS. 103.
Sand-Paper
is
neither a tool nor an appliance, strictly
speaking, but, on account of
its
tool-like action,
The "sand" used
mentioned with them. is
63
crushed quartz, and
is
should be
it
making sand-paper very hard, angular, and sharp. It is in
graded as to degree of coarseness, by precipitation, and then glued to paper.
The
104. strips of
sand-paper
finest
the gradations run o, ^,
1, i^-, 2,
2^,
marked
is
and
00, from which
which
3,
is
the coarsest.
Miter-Boxes are useful in cutting the ends of
wood
an angle of 45 degrees
at
adapted to cutting
;
When
at other angles.
light
they are frequently of wood, like the
one represented by Fig. 219, they are usually made by the
workman himself. A wooden miter-box is composed of three pieces a bottom and two sides. It is necessary that the bottom piece
—
be uniform
in
width and thickness, and have jointed edges, and
well to prepare the other pieces in the
it is
box
the
is
nailed, the sides should
face of the
bottom piece
Lay
a working-face.
;
same way.
After
be square with the outside
this surface
may now be used
off across the working-face
two
as
lines at a
distance apart equal to the width of the face, thus forming with the outside edges of the box, a square.
The
diagonals of this
marked
square will represent the two oblique cuts, one the one taken by the saw, Fig. 219.
from the points thus
lines
cuts
;
the sawing
fixed, as will
and
be useful in making the
then done with the back-saw.
is
c,
Project up the sides such
No
special
directions are required for laying off the cut d.
105.
now
Iron Miter-Boxes are
in general use.
The
curacy with which work
^^
R
Fig.
130
ac-
may
be done by the use of one will
more than compensate any
bench-worker invested in
it.
for
the
Fig.
money may be taken
130
as a type
;
the
work
A
BENCH WORK
64 is
supported by the frame as shown, while the proper position of
the saw
is
maintained by the uprights B, which, in the sawing
process, slide at
WOOD.
IN
down
into the standards C.
The saw may be
set
any angle with the back of the box D, by swinging the frame
E, which supports
the standards
suitable fastening operated
Bench Clamps
1 06.
C
E
;
is
held in position by a
by F.
are useful in holding two or
of material together temporarily.
They
more pieces
are particularly valu-
able for keeping pieces that have been glued, in place until they are dry.
Wooden clamps, or hand-screws, are of the form shown by The whole length of the jaws, AB and A'B', may be made to bear evenly upon the work, or to bear harder at certain points, as A A' or BB'. Iron clamps afe illustrated by Fig. 132, but the mechanical Fig. 131.
arrangement
differs in different
makes.
Such clamps are very Fig.
useful in
many
kinds of work, but,
all
133
things considered,
it
is
doubtful whether they are as serviceable to the bench-worker as the
wooden ones
107.
A
just described.
Grindstones are selected with reference to their "grit."
coarse, soft-grit stone will
idly than
one of
remove material much more rapsurface produced will be
finer grit, but the
very rough compared with that produced by the other.
Thus,
BENCH TOOLS. when
it is
65
necessary to remove material for the purpose of giv-
ing shape to a casting or forging, the coarse, soft-grit stone better
;
but
a smooth cutting edge
if
grit
should be used.
fine
and
soft
must vary from 500 pending upon with which
it
For wood-working
to
1000 circumferential
runs.
at its
is
feet a minute, de-
one of
circumferential speed
ence of the stone.
4' or 5'
As a
This
may
if
give
good
a stone for
rule,
maximum speed when, its
steadiness
not be well to run a 20" stone
limit, while
would throw water from
By
may
It
run beyond the maximum.
tool grinding
a stone rather
diameter, and the accuracy and
its
beyond the minimum results if
tools,
The speed of a power grindstone
found best.
is
is
required, one of fine
is
run
faster,
it
face.
meant the speed of the circumfer-
is
is
found by multiplying the diameter
of the stone, in feet, by 3.1416 (ratio of diameter to circumference), which will give the circumference of the stone, in feet,
and 1
this
product by the number of revolutions per minute. 1
Example
I.
—A
4' stone is
run at 30 revolutions a minute; what
is its
circumferential speed?
The circumference 4'
of a 4' stone
X 3.1416=
is
12.56'.
This would be the speed of the stone per minute; but, since
it
12.56'
Example tial
II.
— It
is
makes 30
X 30 =37 6 -8°'
The circumference
How many
x 3-1416=
of revolutions
280'
I
revolution
is
revolutions should
it
make?
-i-
if it is
were
=
to
make
1
revolution per
280' per minute, and therefore
made must be
7.85
is
7.85'.
But the circumferential speed
number
make but
= 2.5'.
This would be the speed of the stone
the
to
or 377' (nearly).
of a stone 2.5' in diameter
2.5'
minute.
were
desired that a 30" stone should have a circumferen-
speed of 280' per minute.
30"
if it
revolutions, its speed
36 (nearly).
BENCH WORK
66 1 08.
Water
IN
WOOD.
used on a stone as a means of carrying
is
the heat resulting from friction between stone and tool
washes away the particles of stone and
steel that
the grinding, and which, without the water, would
it
off
also
come from
fill
the inter-
between the cutting points of the stone, and make the
stices
smooth
surface so
A
;
grindstone,
Water
water.
moisture
will
more
useless. in use, should not stand in or over
softens a stone,
be found
When
exposed.
be
as to
when not
softest
brought into
and one unequally exposed to in such places as are most use, the softer parts wear away
rapidly than the others, causing the stone to
Water
of round."
is
best supplied from a tank, or from service
pipes, so arranged that
it
may be
shut off
when
the stone
running, the drip-pan under the stone being at fectly
drained.
become untrue and need
True
To
is
a Grindstone.
not
times per-
all
After every precaution has been taken,
stone will in time 109.
become " out
the
attention.
— When
a stone becomes
untrue, or the outline of the face, which should be slightly convex,
becomes concave,
it
may be
corrected by using a piece of
a turning tool, the stone being run dry.
soft iron as
may be
of the tool
explained as follows
small particles of the stone to
:
The
action
the soft iron allows
imbed themselves
in its surface,
from which position they act against the revolving stone, and
done by these imbedded particles and not by the worn in the process, however, and, as its cutting surface becomes enlarged, it should be turned to bring
the cutting iron.
a
new
is
The
latter is
angle or face into action.
This operation
formed by using a piece of gas pipe (about 1")
no. Truing Devices grindstones.
They
are
now
is
easily per-
for a turning tool.
generally attached to
are of several forms, of
power
which that shown
by Fig. 133 may be taken as an example. The base of this attachment is secured to the grindstone frame as near the stone as may be convenient. A is a hardened steel screw which revolves
BENCH TOOLS.
67
The frame in which B runs is pivoted movement of the hand-wheel D, B will move forward in the direction of the arrow. By adjusting the hand-wheel D, A is brought into contact with the on
freely
its
bearings B.
way
at C, in such a
face of the
moving
The
move
it
not prevented by
its
thread would
and
stone,
begins to revolve.
it
that by a
at
once
action of
Fi
133
its
endwise, were
The
bearings.
advancement of the thread, which is not met by a effect of this angular
corresponding
When
stone.
movement
lateral
the parts in contact,
of
a shearing cut across the face of the
is
the screw
becomes
dull
may be
softened and
of
oilstones
it
recut.
in.
— The
Oilstones.
most useful
found near Hot Springs, Arkansas. classes,
known
Washita
much
to
is
all
are
are divided into two
Arkansas stone and the
the trade as the
The former
stone.
They
of very fine grain, appearing
It is used in sharpening the most and produces an edge of remarkable The Washita stone is much coarser in grain, with a
like white marble.
instruments,
delicate
keenness.
color sometimes almost white, but lines of a reddish cast.
It cuts
more frequently shaded by
with rapidity, and with
much
greater delicacy than would be expected of so coarse a stone.
Probably no better oilstone exists for sharpening wood-working
and
similar tools.
112.
water
is
Oil
is
used on an oilstone
used on a grindstone.
as free as possible
A good oil is
quality of
frequently
113.
from
sperm
all
for the
To be
same reason
serviceable,
it
that
should be
tendency to become thick or gummy.
oil,
or even lard
oil,
may be used
;
olive
recommended.
—
Form of Oilstones. It is evident that if oilstones made round, and mounted like grindstones, they could
could be
BENCH WORK
68 be used more
WOOD.
when only a
effectively than
The reason
able.
IN
small block
they are not so mounted
is
is
avail-
that, in their
native bed, the whetstone layers are traversed in every direction
by veins of hard quartz, which, stone,
allowed to enter into a finished
if
would destroy the cutting edge of any
be applied
to
it.
It is so
uncommon
might
tool that
to find large pieces of
whetstone free from the quartz, that disks above 4" or 5" in
diameter can be afforded only by those to whose work they are indispensable.
For bench purposes, Washita stones are about 1" X 2" x 7"; but no attempt is made to have them Fig 134 f an y un iform size. Such a stone, when .
set into a block
and provided with a
cover to keep out the dust,
See Fig.
for use.
134.
ready
is
Its
surface
should be kept as nearly as possible straight, in the direction of its
length,
When
and should never be hollowed across it must be trued.
breadth.
its
out of shape
114.
whose cross-sections are round,
Slips of Washita stone
square, triangular,
by the
trade.
A
etc.,
supplied
are
wedge-shaped
slip
represented by Fig. 135 it is a form extremely useful to the bench-
is
;
worker.
115.
To True an Oilstone, mix water with sharp sand until is thin enough to run. Apply a quantity of this
the mixture
to the surface of a flat is
to
be trued
in
board or plank, and, with the face that
contact with the sand-covered board,
the stone about, frequently changing the direction of
Under this treatment, the up rapidly. If the sand
may be
replaced by new.
its
move
motion.
surface of the stone will be evened that
is
first
applied becomes dull,
it
BENCH TOOLS.
6g
Another, and usually a more convenient way, consists in subsand a sheet of sand-paper tacked over the
stituting for the
edge of the board.
Coarse paper
may be used
at
first,
afterwards a finer grade selected for finishing the work.
and
PART
II
?>KC
BENCH WORK. No work
116.
at the
bench (9-13) is more important than and production of lines. Careless-
that relating to the location
ness or want of
skill in this will
To
ished work.
the beginner
even hard, to stand a shaving
;
at the
always be manifest in the
fin-
may seem monotonous, and
it
bench several hours before turning
but he must understand that a scratch cannot be
and
called a line,
and accuracy are the chief
that patience
requisites in skillful manipulation.
117. Location of Points (14-17).
begin somewhere.
Note.
greater the
more chances
to begin, the
1
The
— The
—
All
measurements must
number of
points from which
there are for mistakes.
material, or "stock,"
needed
for the
Thus
in
exercises of the
course should be straight-grained, free from knots, well-seasoned, and
machine-dressed. to
be preferred.
By
A good
quality of either white pine or yellow poplar
Good work cannot be
clone in
easy steps the operations to be performed become more and more
difficult.
The
student should not advance to a
new
exercise until the pre-
ceding one has been completed in a good, workman-like manner.
of the exercise.
The
course
Otherwise, a careless habit
may appear
brief,
which
it
leads.
is
work
in
any of the
After the fifteen exercises have been finished,
remains, any ordinary piece of bench
fail-
encouraged.
but experience has demonstrated
pleteness as a preparation for constructive
A
be followed by another
ure, unless the result of accident, should invariably trial
is
poor material.
work may be undertaken.
its
com-
lines if
to
time
BENCH WORK
-J2
measuring from take.
If
E to E,
G is located
WOOD.
IN
Fig. 136, there
is
one chance
by measuring from E, then
for a mis-
in the loca-
Fis. 13G
\b
b
END ELEVATION.
SIDE ELEVATION ("FACE A).
G there are
tion of
two chances
G
E, another in locating
urement from E, there
but
;
for a mistake,
if
G
is
— one
as in the case of E, but
is,
in locating
located by direct meas-
one chance
of error.
In locating a point by measuring from a point or line already fixed, it is necessary to make some kind of mark to indicate results in a
mark
Fig. 136, a " point" through
which
the distance.
Haste in such work frequently
similar to that
shown
a line
may be drawn
at
E,
with ease but with doubtful accuracy.
A
dot from a sharp pencil, as shown at E, Fig. 136, is much better ; but if by reason of roughness of surface such a dot is too indistinct, two lines meeting each other at an angle may be used, G, Fig. 136, the point of juncture indicating the
required location. 118. plane.
A
Jointed Face
The
necessities
is
a surface that has been
made
faces at right angles to an adjoining face, that to
term has come to mean
a true
of practice so often require jointed
many
the
not only a true plane, but such a sur-
face at right angles to another, from
which
it
is
said to have
been "jointed." 119.
A
Working-Face
is
one selected as a guide
for opera-
be performed on an adjoining face. For accurate work At this face, all measurethe working-face must be jointed. ments have their beginning, and by it all lines are produced. If tions to
a piece of material
A
and
is
to receive lines
C, Fig. 136, either
on two opposite
B or D may be
sides, as
used as a working-
BENCH WORK. face,
but not both
ing-faces
on
if
;
B as
136, from
A
as
and B,
for
on four
faces, as
A, B,
example, must be work-
must be working- faces.
six faces, three
example, suppose as ab, will then
to receive lines
if it is
;
and D, two of them,
C,
73
For
be made on the surface A, Fig.
lines are to
a working-face
;
those running across the piece,
be made perpendicular to B, and those running
If, on the contrary, the worksome of the lines are made from B and some from D, their truth will depend not only on the as individual surfaces, but also upon their truth of B and parallelism, and hence there is a double chance of error. Only one face, therefore, should be used from which to do the lining
lengthwise, as cd, parallel to B. ing-face
is
disregarded, and
D
for
a given surface.
as
A, B, C, and D, and
lines
D
on
A
and
If lines are to
C can
A
the
beam
It will
all lines
The
No.
1.
it
is
to
all
and
necessary to use
— Measuring and
stock required
be well
will
B
of the square on only two faces.
is
Lining.
if inches thick, 4 inches wide,
1
it
on
be seen, therefore, that in
and 4 feet long, or, as usually written, if" x 4" X 4'. shows the completed exercise. To aid in following
D,
four sides,
all
are the working-faces,
true square in section,
EXERCISE 120.
be made on
B
be made from B, and
can be made from A.
making a piece a
and
Fig. 137 directions,
work A, B, C, and by Fig. 137 (End Elevation), and and B, working-faces.
to letter the four faces of the
respectively, as indicated
mark two of them,
as
A
Operations to be performed on Face A, from Working- Face, Fig. 137. 121. pencil
1
Spacing with Pencil and Rule (18).
and
Fig. 137
rule,
is
lay off points a,
broken
in
B
— By
as a
use of
1" apart along the whole
accordance with the principles given in
6.
BENCH WORK
74
WOOD.
IN
length of the piece, the line of points being kept straight by preserving a uniform distance between them and the workingface
and
B. will
may be
This distance
be
anything that
convenient,
is
determined by the eye.
sufficiently accurate if
Fig.
137
Scale,
2
=
A
i
a
a
—a a a a i
i
M-J '
a
=a a \a a a a a a Working Face B. Face A. i
'
'
i
'
'
'
a
a
a END ELEVATION
Working Face A. (I
Face B.
Gauged Lines
Face g
to be J"
apart.
D
Workin g Face
B.
g
V 16
-16-
FaceC
and Framing-Square (19The points having been located, draw through each a 21). square and pencil. line, as ab (Face A), using the framing122.
—
Cross-lining with Pencil
BENCH WORK. While a
line
75
being produced by the outside of the shorter
is
leg of the square be, Fig. 138, allow the longer leg ab to drop
down
so that
its
inside
edge may be firmly pressed against the
When
working-face, as indicated by the arrows d.
the progress
Fig. 138
JT a'
b
|ct
Tel
of the lining causes the leg ab to project beyond the work so
much
as
shown
at a'b', Fig. 138,
to
be imperfectly guided by the working- face, as its
position should be reversed as indi-
This method must be observed
cated by the dotted outline. in using
— Lay
off points
apart, the first point in each case
working- face. to
tool, a$ the try-square, bevel, etc.
Chalk-Lining (36).
123.
ad \ u
any similar
Through the points thus
on
lines
ab and
being \" from the
located, chalk-lines are
be made, as shown by face A, Fig. 137. Insert the awl at the first point on the line ab, and drawing
the cord tight with one hand, apply the chalk with the other,
beginning at the awl. chalk
is
make
it
Care must be taken that the cake of
not cut to pieces by the cord.
A
easy to hold the cord under the
thumb
as to form a small shoulder
on the chalk,
little
practice will in
such a way
Fig. 139,
which by
BENCH WORK
76
IN
WOOD.
the friction of the cord will be gradually carried across the face
of the cake
;
another
is
then formed to take
the cord has been chalked, stretch
Fig.
ad
that corresponds to the point is
by
Fig. 140,
Then
When
place.
its
over the point on the line
140
awl
inserted.
it
raise the
on the
line
ab at which the
cord near the middle as shown
and by suddenly releasing
it,
cause
it
" to " snap
on the surface of the work. In snapping, the cord should be drawn up vertically, for if drawn afran inclination as shown by a, Fig. 141, a wide blurred line will be produced.
operation
this
each of the points, finishing face
A
as shown.
clear
g.141
Repeat
for
Each
line
and well-defined.
should be
Try
to
make
each one better than the preceding.
Never snap
more
than
once
be-
tween the same points.
Operations to be performed on Face B, from
Working- Face, 124. the
Fig.
Lining with Pencil and Try-Square (22).
beam
A
as a
137.
— Hold
of the square firmly against the working-face, and,
using the outside edge of the blade as a guide, continue across face
B
on the working-face which were made by use If the work has been well done, the will be sharp, straight, and parallel, as shown by ab, cd, Face B, Fig. 137. the lines
of the framing-square. lines etc.,
BENCH WORK.
77
—
The bevel Lining with Pencil and Bevel (23-25). an angle of 45 degrees, and the lines ag,fg, drawn from the points made by the intersection of the already drawn and the working- face, Face A, Fig. 137.
125. is
to be set at
etc.,
lines
Hold
beam of
the
the bevel firmly against the working-face,
and use the outside of the blade to guide the pencil. beam of the bevel bear firmly on the working-face.
"Gauging" Lines with Pencil and Rule.
126.
lines, as ik, hi, etc., are
to
Let the
— These
be spaced \" apart, as shown by
Face B. Grasp the
rule at a proper distance
from
end, in the
left
hand, and press the forefinger against the working-face
to
which the
rule
its
With
perpendicular, as shown by Fig. 142.
is
hand apply the pencil to the work, and at the same it against the end of the rule. In this way, the pencil against the rule, and the fingers of the left hand against the right
time press
the working-face,
ducing a
move along
the length of the work, thus pro-
parallel to
line
the working-face.
It
is
not necessary to lay off points, since the distance
between the pencil and the edge can always be
known by observing
the
graduations of the rule.
In making pencil will be
a
line,
more
kept in position siderable force
is
the
easily
if
con-
used in pressing
it
against the
prevent this force from displacing the rule,
by a greater force acting c
and
it
rule
;
to
must be met
in the opposite direction.
See arrows
d.
This
is
a rapid
method of producing lines parallel is not demanded.
working-face, where exactness
to
the
BENCH WORK
y8
IN
WOOD.
D
Operation to be Performed on Face Working- Face, Fig. 137.
A
from
Spacing by Use of Scriber (37) and Rule. and lines made with a pencil, while accurate enough 127.
as a
— Points many
for
purposes, are too inexact to define the proportions of different parts of a joint.
Where good
made make
with a scriber.
The
of any kind
fitting
the pencil should not be used, but
required,
is
points and
all
lines
be
and should
scriber should be sharp,
a clearly-defined cut, not a dent.
Using the
rule, then, to
determine the distances, substitute
the scriber for the pencil, and, following the dimensions given
(Face D, Fig. 137), lay
off points
through which the lines ab,
along the length of the work
cd, etc., are to
be drawn.
Lining with Scriber and Try-Square.
128.
— Through
the
points already placed, scribe lines, as ab, cd, etc., with the trysquare.
Care must be taken that the advancing edge of the scriber is
not turned out from the square blade
it
is
likely to "
line.
such
in
Neither should the scriber be turned in so
crowd the square from its position. can be scribed easily and rapidly. 129.
;
a
case,
run out " from the square and give a crooked
After a
Lining with Scriber and Bevel.
angle of 45 degrees and, using
little
much
as to
practice, lines
— Set the bevel
at
as before, scribe lines
it
the ends of the try-square lines, as
shown by 130.
35).
be, ad, etc.
Gauge-Lining
most ready means production
curate
to
As shown
beam
(32-
The gauge provides
parallel
an
from
a in
the
for the ac-
of
lines
working-face. Fig.
of the gauge
143,
B
the
carries
BENCH WORK.
79
B
a steel spur C, which does the marking.
head D, which
also
carries
a
on the beam. To use the gauge, adjust the head so that the distance between it and the spur C is equal to that between the workingis
adjustable
face and the required line ; then close the fingers over the head and extend the thumb on the beam towards the spur, as
shown by
Holding the gauge
Fig. 143.
the head against the working- face,
work, and the line
To
be produced. the
first
make a which may be
should
manner, bring
the gauge along the
will
/f^T**' ^^/^
pre-
vent the spur from sticking,
in this
move
stroke
light line,
strength-
ened by a second, and
__f3L_,
C^fc^\
f^MM\
<\3^\\ y \ v\y ^—A^j£^fe^i
l\\
fejM\\y
i^ S- fef-l M- J
^
-
,
^^^^^:~r^>^>J/ -^ ^~^^_ ^JP
even a third passing of the gauge.
The depth
ot the line in
each case
regulated by
is
turning the gauge as indicated by the relative position of
and X,
Fig. 144.
It
is
obvious that no spacing
when this tool is to be used. By use of the gauge, lay Face D, Fig. 137.
off
is
1" apart the lines fh,
Operations to be performed on Face
Working- Face,
Fig.
C,
from
Y
necessary
eg, etc.,
B
as
a
137.
131. The lines on this face are to be used in Exercise No. 3. By applying the principles already developed (121, 122) locate
the lines as shown by the drawing, Face C, Fig. 137. This work may be done with the pencil, the lines ab and a'fr' being " gauged " by use of the rule (126). The line cd End Elevation, may be made in the same wav. t
BENCH WORK
8o
IN
WOOD.
r\
V
!
i i
ff 10
>? f
/ \ \
)
i
III I !
^
ii I.
1
I
1 /
i
!
/
\
I
I
/
. \
I 1
ii
L_£
I
\
!
\
w
BENCH WORK.
EXERCISE
81
No.
2.
Practice with Chisel and Gouge (39, 40, and 42)
The
stock required
shows the
Fig. 145
is
arcs of circles,
in the
is
8".
needed,
of which are
all
foregoing exercise, except the
which must be put
B are working-faces.
and
piece
X 4I" X
lines that are
produced as explained
A
£"
t
in with the dividers (26);
An end
elevation of the finished
represented by Fig. 146.
Fig.146
To remove the Portion abc, Fig.
132. best, in
removing surplus wood with the
the
grain, as
the
grain
is
any attempt quite
sure
to
to
carry
result
splits
ahead
of
it,
and
the
work should be held
A
A
edge along action, the
Fis-
its
in the vise with
toward the operator.
Mh i\
Beginning at one end, make suc-
cessive cuts with the chisel, as
by
cutting splitting
1" chisel will be found of convenient
size.
Fig. 147.
Each
{i.e.
shown
stroke of the chisel
should cut almost to the quired
full
depth
re-
remove a shaving from the
face of nearly the whole triangle abc),
the thickness of the cutting varying with the character of the
material
always
cut across
a
In removing the portion abc,
the working-face
It is
the
pre-
vents the operator from controlling course.
—
wood,
chisel following the grain of the
which
in
145.
chisel, to
and the
\
147
BENCH WORK
82
strength of the operator.
WOOD.
IN
It is best,
however, to go slowly,
the chisel will not be properly guided
Fig.
strength
148
The
To smooth
it
will
through
it
produced
surface thus
not be smooth, but
the line.
foi
the workman's whole
required to push
is
the wood. will
if
be true to
a wide chisel
it,
should be used, as shown by Fig. 148,
to
it
at the
It will
in
same time
and a longitudinal movement imparted being pushed forward.
it is
be noticed that both chisels are applied to the work
such a way as to turn the shaving from the bevel, and not
from the
flat face.
This
is
done that the
able as a guiding surface, which, solid material
back of the cut (see
straightness in the forward
b,
movement of
face
flat
when kept
may be
avail-
in contact with the
Fig. 148), will insure
the cutting edge, and,
consequently, accuracy of work.
133-
—
With the To remove the Portion defg. Fig. 145. work flat on the bench, face A Trig. 149 uppermost, place a f " chisel so as to bring its cutting edge in
fgffi
the
position
line hi,
which
occupied
by the
about
y from
is
the end of the work. drive
mallet, cally ,
protects the ends of the
work, which would be mutilated by the benchstop
if
they were placed
contact with
in direct it.
Toeing Nails.
161.
— The advantage
to
be
derived from toeing a nail lies in the fact that it
" draws "
always
in
the direction in which driven.
If driven
shown by a, will draw
Fig. 185,
it is
as it
B
both
in
A
upon
a horizontal
and
in a vertical direc-
tion,
and will thus ingood contact be-
sure
tween the parts of the joint.
The
nails
driven and
having been set,
each of
the four sides
may be
given
smooth-
a
final
ing by a stroke of the plane.
BENCH WORK.
EXERCISE The
stock required
8.
— Splayed
if'x if "x
is
the necessary lines are is
No.
shown by
I03
16",
Splice.
from Exercise No. 4
Fig. 186.
The
;
finished piece
represented by Fig. 187. Fig.187' Scale,
3=1'
I
I
PS Si END.
ELEVATION.
Lay Let the faces A and B be the working-faces. on face A line a, and from a, the lines b, c, d, 202, scribe the line ab, i"
ELEVATION
Fig.
(the
thickness
working- end,
of
X)
and
from the
continue
across the working-edges.
it
Set a
f ", and from the workgauge the line cd on the working-end, and extend it on the edges until it meets the exgauge
at
ing-face
tended
D,
A
line ab, as
Fig. 202.
shown by
From
ELEVATION (FACE
A.)
ELEVATION (FACE
A.)
face
the working-
end of X, with the same gauge, make the line ab on the two faces
A
and C.
Produce the remaining on X, cut the mortises, and off Y by X, as in the last
lines
lay
exercise.
Fig.
be seen
X does
not extend across the
Y, and, consequently, the
piece
finished
shown by
is
of the
end grain
"5
BENCH WORK.
In cutting out around the pins (F), the delicacy of the work
does not is
demand
the most delicate chisel, but one as large as
convenient should be used.
sions given
Finish the joint to the dimen-
by Fig. 201.
EXERCISE
No.
13.
— Blind
Dovetail.
The
stock required
is
two
|"
X 3J" X 4"
each
pieces,
jointed
edges
and
parallel
one end squared. The finished joint is shown
by elevation (face
in the
e.)
The
203. is wholly
with-
square abed, and, consequently, no
end grain shows on any
175.
Fig.
dovetail
face.
With the square,
lay
on the
off
working- faces and two edges of each piece of material, Fig. 204, the lines ba, elevation ^ace
cd, dk,
a.)
on the ends of each piece the Fig.
'-2
line
ef.
Kig.
0-4
Scale,
c
b
£ PLAN (FACE
D.)
A-
ELEVATION (FACE
A.)
«0
END
ai,
A
and from the working-face
i2 0,~i 8
=
1
and
gauge
u6
BENCH WORK
TTigi.S06 Scale,,
a— a'
IN
WOOD.
BENCH WORK. degrees) and scribe the dotted line
then cut to line with a chisel. glue,
and
I^ig.
finish to
207 *-*
dimensions.
e,
When
Fig. 205,
117 on each piece
the joint has been fitted,
BENCH WORK
iS
IN
WOOD.
Three pieces of stock are required, each jointed
to
dimen-
:ll PANEl
egg"
ELEVATION.
sions as follows
4"
for the stile,
:
X 2 2"" X 9" for the rail, i|" X 4" X 6i" and for the The panel j" X 5" X s£". 1
;
)
work
finished
is
shown by
ELEVATION.
Fig. 212.
The mortise-and-tenon
joint between the stile and rail, and position of its parts, is shown by Fig. 213. The width of the mortise and the tenon should be equal to the
178.
both
in the size
1 width of the f " chisel. so placed as to make the
the
1
rail.
be noticed that the
lines are
extend beyond the lower edge of
This extension, or " horn," as
The nominal width
width.
It will stile
it
is
called,
is
of a chisel does not always agree with
for the
its
actuaj
BENCH WORK.
19
purpose of re-enforcing the end of the mortise during the ting,
— a recourse which must always
in the finished
After
all
Having
work
closely approaches the
end of the
the jointing has been done, the horns
material.
may be
cut
laid off the necessary lines for cutting the mortise
the tenon, very light lines, as cd
made on both
stile
and
rail to
Scale,
and
fit-
be had when the mortise
c'd',
off.
and
Fig. 213, should be
guide in cutting the chamfers.
3=l'
BENCH WORK
120 driven
are
together,
indicated.
WOOD.
IN
be dipped
to
This method
in
of wedging
glue
forms
and driven a very
as
strong
joint (250, 251).
181.
Round
on the bottom and side, it to the back of the one in the rail, and one, b,
the edge of the panel
shown by a, Fig. 212, and frame by two 1" No. 8 screws
as
fasten
—
in the stile (258).
In inserting screws, the outside piece (in
182.
panel) must be bored for each screw. sufficiently large to allow the if
the
wood
hard,
is
it
The
screw to pass through easily
must be enlarged
at the top, or "
The
terbored," to receive the head of the screw.
which the screw holds
this case the
hole should be
(in this case the frame),
if
and,
;
coun-
piece in
of soft wood,
need not be bored unless there is danger that it may split, in which case a hole should be made, in diameter about two-thirds
The
that of the screw.
depends
largely
necessity for a hole in hard
wood
A
short,
on the proportions of the screw.
large-wired screw will stand almost any service, while a long
slender one will frequently be twisted or broken under the strain necessary to
drive
it
wood which
into
is
only moder-
ately hard.
Judgment must determine when the screw is driven sufbut The head must bed well into the wood
ficiently.
there
is
;
danger that
it
" forced so far as to " strip
may be
the thread, and that, as a consequence, the screw will not
hold (96,98).
Never allow the screw- driver screw while the 183.
screws.
latter is
to
from the
slot of
the
Brad-awls are useful in preparing the way for small
The
cutting edge should always be placed across the
grain so that the fibers will be cut, to close
slip
being driven.
up again when the
tool
and not simply pressed apart
is
withdrawn.
The
difference
BENCH WORK. in effect
may be
121
seen by comparing, Fig. 214, A, which shows
a proper action, with B.
Fig.
EXERCISE
314
No.
15.
— Paneling.
This exercise consists in making that portion of the panel door, Fig. 211, included within the rectangle efgh.
Fig. 2i 5 Scale,
3'
l'
7777
BENCH WORK
122
WOOD.
IN
Three pieces of stock are required, each jointed sions as follows: stile
panel
strip J" by Fig. 215.
184.
x
if"
X
i-J-"
x
9";
i£"
rail
The completed
18".
Fig. 216, three
groove, or " plow," which
215
new is
dimen-
to
x 2^" x 6£";
exercise
In considering the joint between the
shown by a, Fig.
2*"
x
stile
is
and
shown
to receive the panel, as
as
rail
features will be observed;
the
shown
at
the beads /,/', and the mitered corner cd, which
;
allows the parts to be
plowed and beaded
as shown, without
affecting the mortise-and-tenon joint.
Follow the dimensions, and
line for the mortise
in the preceding exercises, supposing the rail to
indicated by the dotted outline djc\ Fig. 2
be of the form indicated by Fig. Scale,
h-
*
1\
i
efd.
216 %*>£
and tenon
as
be of the form
and the
stile
to
This done, add the lines
ec,
1
6,
BENCH WORK.
No
185.
special direction can be given for using the
(85), except that it
will
be
it
is
it
plow
used from the working-edge; but
to be
safe to practice with
before applying
it
on a piece of waste material
to the work.
3=l'
Scale,
Next, the beads /,/, Fig. 215, are to be formed on the rail and stile, that is, along the edges
186. inside
123
edge of both
marked
b,
Fig.
216.
the use of the plow,
What has already been may also be said of the
said regarding
beading-plane
(84).
The mitered
corners are
now
to
be formed by cutting with
the back-saw to lines already made, and then the joint between stile
and
rail, fitted
in Exercise
No.
and wedged as Fig.
14.
The frame having been made may be given to the panel. The panel strip, al-
ready, attention
ready jointed, must be "matched"
by forming the tongue b and the groove
a, Fig.
This opera-
217.
tion brings into use the J" match-
ing-planes (82), which should
first
be tried on a piece of waste material.
The bead
c,
Fig. 217,
is
218
BENCH WORK
124 box
IN
WOOD.
obtaining the angle of the ends.
in
The
pieces one to another will be most easily done in order, as a, b,
side
b,
etc.
in the
square.
To
The opposite guide cc may be By using d the work will be cut off
piece at a miter.
same manner.
hold the pieces of the panel together, and to fasten
the panel to the frame, light brads
oblique ends
what
a, while
bottom of the box, must be pressed against the on which position, the saw, guided by the box as shown, in the
will cut the
used
of the
they are cut
In using the miter-box, Fig. 219, the work
187. resting
c,
fitting if
is,
may be
of the panel strips shown at
perhaps, better, glue
may be
used.
inserted in the b,
Fig.
If the
215, or,
door were
complete, as shown by Fig. 211, the panel would have perfect support in the frame.
PART
III.
ELEMENTS OF WOOD CONSTRUCTION. CARPENTRY. 1
88.
It is
the work of the carpenter to raise and inclose
the frame of a building, to construct to complete all parts
joiner
1
which
floors
its
and
roofs,
give stability to the structure
makes the doors and
windows, erects the stairs,
;
and the
and
provides such interior woodwork as will finish the building as a habitation.
A
single
mechanic may perform almost every
kind of work required in the construction of a building, thus eliminating this distinction of trades classification
we may imagine
the
but for convenience in
;
work
of the carpenter
and
that of the joiner to be quite distinct. It will
be understood that neither carpentry nor joinery
confined to house-building.
be classed as joinery,
it
While
all
bench work may
and principles
that are
involves forms
the logical outgrowth of carpentry.
For
those belonging to carpentry, which will
reason, in the
this
following consideration of joints, there are
presented,
first,
include such as are
used in uniting timbers, as in a frame for a building secondly, those belonging to joinery, which
1
is
properly
will
;
and,
include such
Tredgold's "Carpentry," and "Notes on Building Construction,"
published by Rivingtons, have furnished
under Carpentry and under Joinery.
many
of the facts presented
BENCH WORK
126
WOOD.
IN
as are used in joining small planks or boards.
cannot be rigidly adhered
tion
to,
but
it
This
classifica-
will serve the
purpose
of the following pages.
189.
Any two
may be united in the direction may be united at an angle.
timbers
their length, or they
Timbers united
of
in the direction of their length are usually
subject to compressional stress, which has a tendency to reduce
Fig.
220
Fig.221
J length, as indicated by Fig.
their
which has a tendency
220;
transverse stress, which has a tendency to or to two of these stresses at the
190.
A
Timber subjected
The
bend.
fibers
or tensional stress,
to increase their length, Fig.
bend them,
to transverse stress
(as the
be subject to tensional
is
or ;
must always
convex or has a
lower surface, A, Fig. 222)
strain,
;
same time.
forming that surface which
tendency to become so
221
Fig. 222
will
while the fibers forming the
opposite surface will be brought under compressional strain
This
is
shown by Fig.
Fig. 223,
A
representing a straight timber, Fig.
222
223
C
\A
and
B the
same timber bent.
It follows, then, that
somewhere
between the compressed surface and the extended surface there will
be a
line
which
is
subject to neither compressional nor
WOOD CONSTRUCTION. tensional
strain
such a line
;
a timber, and will be
127
called the
is
neutral axis of
located with sufficient accuracy for
the purposes of this work, if drawn midway between the upper and lower surfaces, as shown by the dotted line. CD, Fig. 223.
In the timber that has been forced into a curved form, Fig. 223, the fibers within the neutral axis are
under no
strain
excepting that required to hold the compressed portion to the
extended portion; but the conditions are found rapidly as the examination extends to fibers
remote from
change
In other words, the strength of such
this axis.
a timber increases rapidly as if
to
more and more
Fig. 222 represents a 2"
its
depth increases.
x 4"
For example,
timber (2" wide and 4" deep)
supported at B, B, and capable of sustaining 200 pounds at C, it
can be shown
that,
if
the depth
the same, by substituting a 2"
x
is
doubled, leaving the width
8" timber,
times the original load, or 800 pounds
;
it
will sustain
while
if
doubled, leaving the depth the same, by substituting a 4" timber,
it
will
sustain
The law
pounds.
transverse
stress
only twice
the
four
the width
original load, or
is
x 4" 400
that the strength of timbers subject to
is
varies
as
the width and as the square of
the depth. 1
191.
Rankine has given
five principles to
designing joints and fastenings. 1
"To
.
They
be observed in
are as follows
:
—
cut the joints and arrange the fastenings so as to
weaken the pieces
of
timber that they connect as
little
as
possible."
By what has been given
it will be seen that in any body of material most affected in resisting transverse stresses are those lying near the upper and lower surfaces (Fig. 222). In view of this fact, parts 1
the portions
that are to receive a transverse stress, especially
if
of iron, are, in
important structures, formed to present a large amount of material near these surfaces. tions
;
a bridge truss
A is
railroad rail or an I-beam are simple illustra-
an elaboration of
this principle.
BENCH WORK
128
"To
2.
WOOD.
place each abutting surface in a joint as nearly
perpendicular to the pressure which
possible
as
IN
has
it
to
transmit."
"To
3.
which
proportion the area of each surface to the pressure
has to bear, so that the timber
it
injury under the heaviest load to
form and
may be
which occurs
safe against
in practice,
and
every pair of such surfaces accurately, in order
fit
to distribute the stress uniformly." 4.
"To
may be
proportion the fastenings so that they
of
equal strength with the pieces which they connect." 5.
"To
place the fastenings in each piece of timber so that
there shall be sufficient resistance to the giving joint
by the fastenings shearing or crushing
their
way of the way through
the timber."
Complicated forms of
joints are likely to violate
Rule
3.
Joints connecting Timbers in the Direction of their
Length. 192.
A Lapped Joint, shown by Fig. 224, fastened A or bolts B, is clumsy, but very strong.
either
by straps
193.
A
Fig. 225,
Fished Joint
and
is
which are known Fig.
in
its
224
A
m^M
it-
l
ilji
1
employed to
to
shown by marked A
Fig.225
-~,-u--ft-_.-ft.
Fish-pieces
is
as fish-pieces or fish-plates.
ABA 1
simplest form
so called because of the two pieces
may be
of
either
wood
form the fished joint shown
more complicated
5
igr Ji^ilu
or iron,
^
and may be
in Fig. 225, or applied
joints to increase their strength.
WOOD CONSTRUCTION. When
plates,
stress the plates,
of hard
one on each if
A
shown by
Fis-
face.
When
;
and B,
Fig. 227.
226
m
subject to tensional
may be indented, A, Fig. 226 or, ends may be tabled, B, Fig. 226, or keys
of iron,
wood, the
inserted as
equal,
29
subject to compressional stress a fished joint should
have four
if
1
Other things being
Fig.227
^3-
if
may be
the
number
of keys
is
doubled, the thickness of each
diminished one-half without reducing the strength of
the joint, since the total
amount
remain
of abutting surface will
the same.
For transverse of the joint, as
The
be on the sides
Fig. 228.
bolts used for securing fish-
pieces, or for
stress the fish-pieces should
shown by
any
employed as fastenings
joint,
should be
placed
checker-wise, Fig. 228, so that no
two
will
cut the same cross-section.
Fished joints are often used
heavy construction.
By a
in
suitable proportion of parts the joint
can be made almost as strong as the timbers 194.
it
connects.
Scarfed Joints are those in which the two timbers
united are so cut and fitted as to size with the timbers.
make
the joint uniform in
In determining the form of any scarf,
the principles already given (191) should be adhered to as
Note.
— The
student should observe carefully the position of the
he
may
clearly
see the reasons for the different methods of construction.
He
should
lines in the following representations of joints, so that
first
look for the abutting surfaces, and then note their relation to the
rest of the joint.
BENCH WORK
130
Some
closely as possible. ing,
scarfs
WOOD.
IN
by
form are
their
self-sustain-
but compared with the timbers they unite, are weak, and
are seldom used unless strengthened
by
by bolts and
bolts, or
fish-pieces.
195.
A
scarfed joint for resisting compression
When
simplest form by Fig. 229.
its
and
fish-pieces
Fig.
196.
A
Fig. 230.
it
forms an exceedingly good
229
A
the strain tending to
open the
one-third that of the timber.
of Fig.
197. ject to
235 which
A
joint
;
in thickness
is
shown by
In practice
fish-pieces.
it is
equal to
231
this joint is
not often
Fig. 231 shows a modification
will serve excellently for tensional stress.
scarfed joint for resisting tra?isverse stresses
compressional stress in
its
upper portion, and
sional stress in its lower portion (190),
Fig.
embody forms adapted
A
23
supplies the abutting surface to receive
Fig.
employed without
single fish-piece
in
joint.
Fig.
scarfed joint for resisting tension
The key
shown
is
strengthened by bolts
is
and must,
sub-
therefore,
232
to resisting both, as
usually
is
to ten-
added
shown by
Fig. 232.
to the lower side of the joint.
WOOD CONSTRUCTION,
A
198.
scarfed joint for resisting tension
may be made shown by
shown by Fig. 233 234 or, more secure
as
Fig.
;
;
g^fe-^-TC A
199.
r"
'
m
_J__'
s
form
is
'
335
—
'
_^_
Fig. 235.
234
and
by Fig. 236
illustrated
mmm m
'
"
'"
Fig.
scarfed joint for resisting tension
Fig.
complicated as
shown by
as
^^
sometimes made as
is
and compression
or, less
Fig.23 3
stress
131
Fig.
S3 6
'
not so good as the joint shown by Fig. 228,
tranverse ;
but this
d if
in the
latter case the fish-pieces are indented.
Joints connecting Timbers at Right Angles.
200.
when
Halving", Fig. 237, forms a very simple joint, and
well fastened, a strong one.
Fig.
Fig. 237'
1
ra ggir^ ELEVATION.
S3
It
is
frequently employed.
BENCH WORK
132
Beveled-halving, Fig. 238,
is
WOOD.
IN
sometimes resorted
A
view of allowing the load imposed upon
Under ordinary circum-
the arrow, to hold the joint together.
stances this joint
likely to
is
to with the
in the direction of
prove weak, because of a lack of
material at the shoulder near the letter A.
Notching.
201.
which it
is
is
to support
— In placing several timbers upon another
them,
in the
manner represented by
Fig. 239,
usually desired that the tops of the supported timbers be
uniform
in height.
This would not be accomplished by simply
placing them in a row, because timbers of the same nominal size
vary in their breadth and depth.
The ends
Fig. 2-tO
Fig.
of the deeper
241
ones must therefore be cut or " notched," as shown by Fig. 239, to make them agree in depth with the lightest timber of all. Properly speaking,
this is
a preparation for the bearing of one
timber on another, and not a joint ported timber
is
a true joint
made.
is
but
;
the end of the sup-
if
allowed to project, as represented by Fig. 240,
Double-notching requires a notch in both timbers, Fig. 241.
Cogging
202.
is
represented by Fig. 242.
It
has some
advantage over notching in point of strength, inasmuch as the timber
B
has
its full
depth over
its
support.
makes the union between the two timbers, satisfactory as the If the
The
" cog "
A
as a joint, quite as
double notch.
surrounding conditions require
formed near one edge, instead of ber as shown by the illustration.
in the
it,
the cog
may be
middle of the tim-
WOOD CONSTRUCTION. Mortise-and-Tenon Joints.
203.
made on is
133
— A tenon
is
a projection
the end of a timber to form part of a joint
an opening intended to receive a tenon.
;
a mortise
In Fig. 243,
Zis
Fig. ^-4: Fig.
i -=ZB~
the tenon its
;
M,
shoulders
the mortise
and
;
c,
;
c are
R, the root of the tenon S, S, sometimes called the " abutting ;
cheeks " of the mortise. 204.
When
a vertical timber meets a horizontal timber the
object of the joint small, short tenon,
employed.
and a is simply to prevent displacement sometimes called a " stub tenon/' is usually ;
In this case, the tenon should not reach the bottom
of the mortise, but the strain should
be taken by the shoulders.
Sometimes, instead of making a stub tenon, the whole end of
one timber
let into
is
another, and the
first is
then said to be
" housed." Fig.
244
Fiji-. Xi-4,5
li!l
205. joint
When
a horizontal timber meets a vertical timber the
may be formed
stronger,
if,
as
shown by
in addition to the tenon,
or housed, as
shown by
Fig. 246.
Fig. 244, or it is
made much
"blocked," Fig. 245,
BENCH WORK
134 206.
mon to
When
WOOD.
IN
one horizontal timber meets another
practice,
if
employ a double mortise-and-tenon,
Fig. 247,
Fig. a-±6
ported by B.
ence
is
only, the tenon should be
re-enforced by
all
being sup-
on
its
will
With
by the mortises. the mortise ;
is
refer-
on the neutral
while with reference to
lower edge, that
the material above
depth are thus joined, they this
A
This method cannot be recommended, however,
B very much weakened to B only, the best place for
axis (in the center of the timber)
but
a com-
Fig. UZ-±T
t Wm because
it is
the proportions of the pieces are favorable,
If
it.
it
A
may be
timbers of equal
appear as shown by Fig. 248
combination, while strong,
is
ble because of surrounding conditions.
;
not always practica-
For
this
reason both
mortise and tenon are often placed in unfavorable positions, Fig. 3-iS
and the strength
Fig.
349
Sometimes the form
of the joint sacrificed.
249 is used, but this has little in its favor, except the ease with which it is made. A better combination is shown
shown by by
Fig.
Fig. 250, which, although less perfect as a joint,
the purpose quite as well as Fig. 248,
if
may
the timber
is
serve
long
WOOD CONSTRUCTION. between supports. difficulties
employed
Tusk tenons are used
to
overcome the
presented by the forms already described when in
heavy construction.
This arrangement of sur-
faces, Fig. 251, allows the mortise to
Fig.250
135
Fi K 251 .
be
in the center of the
Fig.
ass
BENCH WORK
136 take
all of
WOOD.
IN
the stress, this line should be at right angles to the This, however,
length of the tenon-bearing timber, Fig. 253.
while apparently a well-formed joint, the tenon, which
is
is
not a strong one, for
usually equal to but one-third the width of
256
Fig.
Fig. l'55
H m
"
•
To
the timber, must alone receive the thrust.
by
relieve the tenon
increasing the area of the abutting surface, the
may be
housed, as shown
end
by Fig. 254, or the joint
of
A
may be
strengthened by bolts or straps.
The mortise
for the joint
of the outline abe,
done because a'e.
it
is
There seems
208.
A
and the
shown by
triangle a' be
easier to cut to
down
Bridle Joint
is
fit
is
is
253
is
not
usually
filled.
the line be than
be no objection to
its
made
This
is
the line
this practice.
represented by Fig. 255.
sesses the advantage of having
inaccuracy in the
Fig.
It
pos-
parts so exposed that any
always apparent.
Fig.257
An
oblique form of
Fig.
358
ft ILL
_ bridle joint, Fig. 256,
is
certainly worthy of study.
f\
,A
The width
of the bridle, B, Fig. 255, should not exceed one-fifth the
width of the timber.
WOOD CONSTRUCTION.
A
209.
of the tie
Tie Joint
is
shown by
A
B, the timber
is
may be made
A
210.
bers already fixed. tion of the mortise
joint thus
to serve the
Chase Mortise
Fig. 258. Its purpose
made
to
is
When which
By
Fig. 257.
the insertion
The
joint illustrated
by
same purpose. shown by
a mortise elongated as
is
37
prevented from falling away in
the direction indicated by the arrow. Fig. 197
I
admit a cross-timber between two timthe cross-timber is
is
in place that por-
unoccupied may be
filled,
and the
secure.
JOINERY. The work
211. is is,
usually
where
it
of the joiner, unlike that of the carpenter,
must bear the
test of close
examination.
therefore, necessary that the several pieces of
w ork r
formed, be united by joints that are neat in appearance,
is
made
or so
as to be
hidden from
strong even where there
them
;
It
which a whole
is
sight.
Such
apparently but
otherwise, the parts are likely to
must be
joints
little
upon
stress
become
loose from
shrinking and swelling, and to expose unsightly seams.
Some
the
of
joints
already described, while particularly
adapted to uniting timbers in carpentry, may under given conditions be equally suitable for the smaller work in joinery. It
may
also
be true that some which are treated in connection
with joinery are quite as useful in carpentry. the classification here used only serves to
As already fix
in
mind
general principles governing the adaptation of joints
be
arbitrarily
The best,
adhered
;
it
stated,
a few
cannot
to.
rule in carpentry that
makes the simplest form
of joint
does not always hold in joinery, because the methods of
the joiner admit
of
greater accuracy, and also because the
pieces of material used are smaller, affected
by shrinkage.
and consequently
less
bench work
i38
wood.
in
Beads and Moldings. Beads,
212.
— A single-quirked bead
is
shown by
Fig. 259,
a double- quirked bead
is
shown by
Fig. 260,
a being the quirk
;
Fig.259
and a
staff,
or
Fig.2 60
a/2£/
/
c^^^m^hi n
149
I
BENCH WORK
50
The Frame taken by
239.
Vertical pieces extending the
joints.
are called "stiles,"
and horizontal
these parts should be as narrow as of strength required.
The width
than twice that of the
stile,
and a
made up
although the door
faces
whose shrinkage can
is
full
length of any frame
Each
pieces, "rails."
is
of a rail should never
be more
consideration of Fig. 295 will show
three or
more
affect the
by increasing
of the parts but
of
consistent with the degree
feet wide, the only sur-
width are the two 4^-inch
Large surfaces are covered not by increasing the
stiles.
of
which, as a rule, should not exceed
A
half inches.
that,
A
general,
itself is, in
and horizontal pieces united by mortise-and-tenon
vertical
four
WOOD.
IN
size
number.
their
often inserted to cover the end of the tenons,
fillet e is
which would otherwise show on the edge of the door. 240. The panel may be either fastened to the back of the frame or inserted in a groove, or " plow," formed in the frame to
receive
In either case, provision must be
it.
shrinking and swelling.
When
usually found to
make
into the frame
no fastening
from
its
position.
It
a sufficiently yielding joint.
must
is
fit
made
for
fastened to the back, screws are
When
fitted
needed beyond that derived
loosely
enough
to
draw out on
shrinking, but not so loosely as to rattle.
In Fig. 295, frame, and
A
is
a plain panel screwed to the back of the
the frame about
it
is
stop-chamfered.
This
probably, the simplest combination of frame and panel.
common to
with
work that
or the
all is
panels fastened in this way,
to
permanent
best adapted
be seen from one side only, as a closet door lining of a room.
B shows a plain panel fastened is
it is
is,
In
to the
back of a frame which
ornamented by a molding.
C
differs
from
B
only in being let into the frame instead of
being screwed to the back.
mented by a molding
in the
The
reverse face c
same manner
as C, or
may be
orna-
by a chamfer.
WOOD CONSTRUCTION.
D shows a raised The
A panel and on the other
;
5
I
panel embellished by a rabbeted molding. is
a plain raised panel.
frame may be plain on one side and ornamented the ornamentation on one side
on the other, or the
that of
d
reverse face
I
sides
may be
similar
may
differ
from
and any form
;
embellishment that may properly be applied to board sur-
faces
may be used
in
connection with
this
work.
FASTENINGS. 241.
Pins are employed principally as a means of holding In carpentry one pin, generally„is used in
tenons in mortises.
each
joint, its
diameter varying from one-sixth to one-fourth
the width of the tenon.
It is
from the abutting cheeks the length of the tenon. of the joint,
commonly placed
at a distance
of the mortise, equal to one-third
But
maximum
to secure the
fixed with reference to the character of the material, to the relative thickness of the
mortise.
strength
exact location in any particular case must be
its
In joinery
it
is
and
also
tenon and the cheeks of the
found best to use two or more pins,
and, whatever the proportions of the joint
may
be, these rarely
They
exceed three-eighths of an inch in diameter.
are inserted
very near the abutting cheeks of the mortise, so that that part of the mortise will
between them and the shoulder
not shrink enough to
make an open
of the tenon
joint.
Square pins are better than round ones, but the
more
easily fitted and, therefore,
Drawboring has already been described 242.
Wedges.
(168).
— The most common use
wedges
of
trated by Fig. 213 in connection with Exercise
requires
wedges
to
be dipped
in glue
tenon and the ends of the mortise. in
saw cuts made
expanding
it,
in the
end
as illustrated
latter are
more used.
No.
is illus-
14,
which
and driven between the
Wedges
are also driven
of the tenon for the
purpose of
by Fig. 296, which shows
at
A
a.
BENCH WORK
15-
IN
WOOD.
section of a joint before the wedges are driven,
section of the
finished
The saw
joint.
and
B
at
a
extend
cut should
somewhat deeper than the point reached by the wedge.
If
the tenon
is
is
broad, or
a considerable increase in breadth
if
Fig.2 96
Fig.297 /EDGE. ], WEDGE III 1
more than one wedge must be used. When there are more than two, a large one should be inserted in the center and smaller ones on each side, as shown by Fig. 297, the wedges ready for driving at A and the joint finished at B. required,
Blind-wedging
243. tise
the mortise in
;
is
sometimes resorted
to
when
the mor-
As shown by Fig. 298, the bottom and the wedges started
does not extend through the piece. is
enlarged at
then, as the pieces are driven together, the ends of the
wedges
strike against the
the tenon.
When
bottom
of the mortise
and spread
driven, the tenon cannot be withdrawn.
Fig.298 Fig.
Keys
244.
which are piece,
made when
as as
differ
from wedges
parallel or nearly so.
shown
in
in
299
respect to their sides,
The key may be
the joint, Fig. 197, or, what
two wedges, Fig. 299.
in the relative position
driving
them upon each
may be
tightened.
The
These may be put
shown by A'B,
other, as indicated
a single is
better,
in place
after which,
by A, B, the
by
joint
parallelism of the outside edges, which
are in contact with the joint,
is
always maintained.
WOOD CONSTRUCTION. 245.
Dowels
are
round wooden pins of small diameter
used to strengthen a
joint.
and driven
fit
at a tight
They may be
153
They should be dipped
made
into holes
in glue
for their reception.
and into the shown by Fig. 274. the bench by the plane, or they
carried entirely through one piece
other, Fig. 277, or inserted as
Dowels may be made
may be tion
When
at
planed, they will be improved in sec-
driven through a round hole in a piece of iron or
if
They
turned.
are supplied by the trade, of
in lengths of several feet, so that the
them
steel.
ordinary diameters, and
all
consumer has but
to lengths suited to his purposes,
to cut
and point them.
Shoe pegs serve well as small dowels.
After being dipped in
glue they should be driven in brad-awl holes.
Whenever
fastenings are required to be so placed that sub-
sequent operations bring the cutting tools about them, dowels are preferable to brads or nails, since they
may be planed
off
without injury to the tool.
246.
Nails are
classified
according to the process by which
they are made, the material used, their form and proportions,
and the use
for
which they are intended.
the most
Fig. .^00
f
common
Iron and steel are
when
materials, but
Fig. these would be destroyed by corrosion,
copper and " galvanized
The forms
of
A
170 B
" iron are used.
most importance
to the
bench-worker may be classed as com-
mon and
finishing (or casing)
nails.
Their comparative proportions are trated
illus-
by Figs. 170 and 300, the former
representing a
common, and
the latter 1.
greater strength of the
makes receive
its it
use desirable properly,
when
there
common is
nail
sufficient
and when the appearance
material to
of the
head on
BENCH WORK
154 the surface in
is
not objectionable.
IN
The
WOOD. finishing nail
may be used
more delicate material, and makes a smaller scar on the work. Cut nails are so called because, in the process of manueach nail
facture,
The
cut from a plate of metal.
is
plate has
a width equal to the length of the nail, and a thickness equal to
by
its
Fig.
Generally speaking,
breadth.
Figs.
170 and 300 are
Wire
301
all nails of
the form
nails, Fig. 301, are
now
in general use.
Their strength and tenacity are unequaled. are that
made from drawn
to size
They
wire in sizes varying from
the smallest brad to that of the largest
of
spike.
shown
cut.
The terms used and form, are
The holding power
to describe
cut nails, as
also applied to wire nails.
of a wire nail
is
often inferior
to that of a cut nail.
247. to the
The
length of nails
word " penny,"
now used
arbitrarily,
is
indicated by numbers prefixed
as 6-penny, 8-penny,
— terms
x
which are
though originally they were doubtless
significant.
The
length of nails of ordinary sizes
A A
3-penny nail
4-penny
is
one inch long.
is
given as follows
:
—
WOOD CONSTRUCTION. 248.
Their
Brads are small
size is
finishing nails,
now
I
55
usually of wire.
expressed in inches and fractions of an inch, and
ranges from one-fourth of an inch to two inches.
Tacks are
249.
useless for fastening pieces of
other, but are indispensable
or leather, size
to
wood
to
each
lighter material, such as cloth
be fastened to wood.
They vary
in
form and
with the particular use for which they are intended.
size is
The
is
when
Their
expressed by a number prefixed to the word " ounce."
length of the
A
more common
sizes varies as follows
:
—
x
I
BENCH WORK
56
The
screws
size of
fractions of an inch,
the body
;
this
is
indicated by their length in inches or
and by the diameter
diameter
o,
of the wire forming
expressed by a number which refers
is
to a ''standard screw gauge."
range from No.
WOOD.
IN
The
screw gauge
sizes of the
which represents a diameter
of a little less
than a sixteenth of an inch, to No. 30, which represents a
diameter somewhat greater than seven-sixteenths of an inch.
The
screw two inches long and a quarter would be written 2" x No. 15.
size of a
in diameter
251. Glue glue
is
is
chiefly of two kinds, animal
product obtained
a
from
the
and
refuse
of
Animal
fish.
of
an inch
tanneries
(bone, horn, hoofs, and bits of hide), which is made to give up the glutinous matter it contains by being boiled under pressure. Fish glue is extracted from the spawn and entrails of fish.
in the
As prepared
for the market,
form of cakes, varying
in thickness
both are generally
from an eighth
of
an
inch to very thin chips, according to the quality and character
For bench work these are dissolved
of the glue.
in water,
and
the mixture applied hot. For convenience in dissolving the glue,
a glue-pot
is
used, which
is
an arrangement of two
vessels,
one
within another, the inner being for glue, the outer for water.
Heat
is
communicated
in
any convenient way to the water, and
the water in turn heats the glue.
water
is
to prevent the glue
Gluing.
— When ready
The
use of the vessel of
from burning.
for use, the glue should
of the consistency of thin sirup.
It
be hot and
must be applied with a
brush, in a thin, uniform coating, to both surfaces that are to
be joined, and must be well brushed into the pores of the
wood.
Too much
glue will prevent the pieces from
together in the joint.
The
application
should be
coming
made
as
quickly as possible because the glue begins to cool and set as
soon as
it
is
taken from the pot
;
it
the pieces to be glued are warmed.
will set less
quickly
if
After the pieces have
WOOD CONSTRUCTION. been put together, they should be rubbed
and
surplus glue, until dry
—
finally
clamped
in place
I
to
57
squeeze out the
and allowed
to
remain
at least twelve hours.
In gluing large surfaces, such as veneers which must be secured to their foundations, a considerable amount of apparatus
is
of
Before the glue
required.
chamber, which steam pipe,
is
applied, a heating box or
maintained at a high temperature by
is
coils
used to heat the pieces to be united, and
is
very heavy clamps are required to squeeze the superfluous glue
from the
joint.
It
film of glue uniting
is
important to remember that while the
two pieces should always be continuous,
the pieces themselves should be brought as closely together as possible.
When end
grain
is
to
be glued
it
coated with thin glue, in order to
and allowed glue that
becomes
is
should fill
to dry before the joint
put into the joint
is
made.
is
drawn
be sized
first
;
that
is,
the pores of the wood,
Otherwise, the
off into the grain
and
useless as a fastening.
An example
of
good gluing
is
found
in the
common
lead
wooden portion of which consists of two strips glued together. The line of the joint can readily be traced upon the end of the pencil, but if the work is well done, it will be found that while the joint is a strong one, the amount of pencil, the
glue between the pieces
is
so small as to be scarcely visible.
Liquid glues are supplied by the trade.
They
heating and are, therefore, always ready for use.
require no
PART
IV.
TIMBER AND ITS PREPARATION FOR USE. TIMBER. Timber
252.
which
is
woody material
that portion of the
serviceable for carpentry
is
and
joinery.
If
of trees
the trunks
of timber-bearing trees are cut into sections, they are found to
be composed of concentric cylindrical layers, separated from
each other and evidently quite Fig. 302,
is
distinct.
One
of these layers,
formed each year during the period of growth
of
the tree, though false rings are sometimes produced by inter-
ruptions of growth, such as are caused by drouths, or by the destruction of foliage by caterpillars. ness, in density,
and
in
growth, the length of the season,
which may change from year
The
rings vary in thick-
the rapidity of
and other circumstances
to year.
outer portion of the trunk of a tree consists of a pro-
tective layer of bark.
cambium which
The
color, according to
is
layer,
or
Next
to the
bark
is
the bast, then the
zone of growth, and then the sapwood,
usually lighter in color
and
the interior portions, or hearhvood.
less strong
and dense than
As indicated by
its
the ascent of sap takes place through the sapwood.
containing small quantities of minerals in solution
by
is
name,
Water
taken up
the fibrous rootlets and, passing from cell to cell through
the thin walls, ascends through the outer layers of roots, trunk,
TIMBER AND and branches
the
to
light
and
form
of vapor,
PREPARATION
ITS
leaves.
Here, under the influence of
heat, the greater part of the water
and another
is
given off in the
part, with the salts
These
converted into food materials. leaf to branchlet,
159
travel
it
contains,
is
downward from
through the outer layers of the trunk to the
roots, disposing of
themselves wherever they are needed along
the way, in forming
new wood, new
movements
of water
buds, and
new
roots.
These
upward and food materials downward, take
place simultaneously, the water (sap) moving through the sap-
wood, and the food materials through the bast and inner cortex.
Fig.3 02
As the
tree
grows older, the
cells
next to the center of the
trunk gradually lose their food products, are infiltrated cavities,
into their walls
changing the color in
and other substances
and sometimes into the
cell
the majority of cases,
and
increasing the density of that part of the tree
portion
is
known
in the spring, in winter.
and
as heartwood.
The ascent
;
darker
this
of sap
is
greatest
practically ceases, in the trunk of the tree,
BENCH WORK
6o The growth
of
wood which
usually characterized by
In the
sap.
the
a tree makes in the spring
is
and an abundance
of
thin-walled cells
summer growth
the cell walls are thicker, with
cavities correspondingly
cell
WOOD.
IN
smaller,
and the wood
is,
The slight autumn growth is still more The wood of these three seasons taken the annual ring. yearly growth of the tree
therefore, darker.
dense and dark. together
the
is
—
In some trees the annual rings are scarcely perceptible, while in others they are quite distinct,
upon the kind
of tree as well as
in cross-sections of
Fig.
— a difference which depends
upon the
climate. For example,
oak and chestnut, the spring growth of the annual ring forms a light por-
303
ous zone, which
somewhat
is,
however,
and shades the darker and
irregular
gradually into
denser zone of summer growth. In
other
woods,
like
South-
ern pines, the change between spring and
summer wood
is
sharply marked, and each an-
nual
ring
shows two clearly
denned bands.
where the change of
son
not pronounced, growth
is
correspondingly
less definite.
In tropical re-
gions, is
more regular and the
An
layers
examination of the cross-
section of any tree trunk will disclose the annual rings, also the difference in the
wood.
253.
Fig.
and
appearance of sapwood and heart-
302 shows a portion of such a cross-section.
The Structure
varying in form and
of
size,
Wood
is
entirely cellular, the cells
and performing
different functions
economy of the tree. Some carry water from the roots the leaves, some store away digested food, and others give
in the
to
sea-
TIMBER AND
ITS
strength to the structure and hold
volume
wood
PREPARATION. it
together.
wood, over ninety per cent
of
Most
cells.
of these are long
161
Nearly the whole
in pine, is
made up
and slender, with
of
their
length coinciding in direction with that of the trunk or branch
they have built up
;
and
in
many
cases their
tapering ends
overlap and thus increase the strength and toughness of the stem.
They
are separated most readily in the direction of
their length, as
illustrated
is
by the ease with which wood
Fig.304
III I
splits
" with
of
cellular
all
sides,
cells.
in
To
the
tissue
grain."
Medullary rays are thin plates
which run from the pith to the bark on
strengthening and binding together the longitudinal the unaided eye these rays appear as simple lines
a cross-section
of
longitudinal section.
wood, and
as
glistening
plates
in
a
In the oak, the medullary rays are con-
spicuous in every cross-section, while in some of the softer
BENCH WORK
62
IN
WOOD.
woods they can hardly be traced. Fig. 303 represents a small portion of an annual ring of spruce, magnified one hundred
The
times.
vertical tubes are
wood
or pits
on the wood
and
cells,
ray part of which has been removed.
The
mr
is
a medullary
circular depressions
cells are thin places in the cell walls
Fig.
liilliHiiill l
all
woods
i l
iiilM
of the pine family.
This figure
shows also the manner in which the tapering ends of wood
The specimen
they
3 OS
I are very conspicuous in
;
wood here
cells
from one
of
the needle-leaved trees and shows a tangential section on
its
overlap.
right face, while Fig.
of
given
is
304 shows a microscopic enlargment
of a
TIMBER AND
PREPARATION.
ITS
1
63
tangential section of a broad-leaved tree, white oak, with a
and
large medullary ray, mr,
Woods tic,
also portions of smaller rays.
are hard, soft, light, heavy, tough, porous,
according to the kind and size of the
in the cell walls.
They
cells
and
elas-
and the deposits
are also easy or hard to
work
in propor-
tion as their cells are arranged in a simple or a complicated
manner
;
white pine cuts more easily than oak because
more uniform
it
is
in structure.
254. Markings of wood depend more upon cell arrangement than upon difference of color. In preparing the more valuable woods for market, therefore, the logs are cut in such a way as to display the cell arrangement to the best advantage, thus increasing the beauty of the wood and, as a consequence, its commercial value. This is illustrated in Figs. 302 and 305.
By
cutting the tree in a longitudinal plane through the center
the annual rings lines (a, a, Fig. If
the tree
is
appear
302
),
approximately parallel straight
in
forming what
is
known
as straight grain.
not straight, the cutting plane crosses from one
annual layer to another, forming " flashes,"/, as shown in the tangential section
If
ts.
and the cutting plane
is
marked
the medullary rays are well
along a radius of the
be bounded by portions of the ray which
log, the
will
cut will
extend over a
7
greater or less area, forming "dapples," a
appearance of the medullary for the
term "
silver rays "
rays,
which
Another method of sectioning quarters
and then
when is
is
,
The
Fig. 305.
thus exposed, accounts
sometimes applied
to
them.
that of sawing the log into
into smaller pieces, crossing
by
306
Fi
cuts which expose the annual rings, as indicated
by
Fig. 306.
sawing."
This method
is
termed " quarter-
It greatly increases the cost of
the lumber
because of waste, but at the same time increases strength and enhances
its
beauty,
its
especially in the
case of
those woods in which the medullary rays are conspicuous.
BENCH WORK
64
Beauty of grain
which of a
is
WOOD.
IN
often developed, also, by a rotary cut
is
obtained by revolving a log against the advancing edge
The
broad knife or cutter.
result of this process
broad, continuous ribbon of wood, which
a thin,
is
may be used
as a
veneer upon the surface of inferior woods.
Crooked or
irregular grain
difficult
to work,
which
to
is
and
weakens timber and makes undesirable in
therefore,
is,
be used in the framing of structures
but
;
has
it
Every bend or
value in the realm of ornamentation.
more
it
material
the growing tree disturbs the regularity of
Fis.307
structure
and enhances the beauty
which may sometime be
When,
therefore, a
wood
cut from
trunk.
its
suitable for decora-
is
tive purposes, its value is increased rather
most
common
its
of the boards
than
Some
diminished by such irregularities of grain. of the
its
twist in
markings are knots caused
by undeveloped buds which are covered over
by the
later
growth of the
Fig. 307 shows
tree.
a " dead " knot formed by the breaking away of a branch.
four years, as
The branch was
annual rings are united with
union with later
a living one for
shown by the
is
rings,
and
still
that four
fact
There
it.
later
is
no
ones would
cover the knot entirely.
In woods such as mahogany, satinwood, sycamore, and ash, figures resembling the ripple
due
to a serpentine
marks
of the sea
form of the grain, the
on
fibers
fine sand, are
being wavy in
planes perpendicular to that on which the ripple
and those parts
of the
wood which
is
observed,
receive the light being the
brightest.
Markings
in
wood
are of value in cases where a
finish is required, as in furniture
inside
decoration of buildings.
material are
handsome
and cabinetwork, and
The
trees
those which have plenty of
that
room
in the
yield for
such
growth,
TIMBER AND which are exposed
to
PREPARATION.
ITS
winds that bend and
1
twist,
65
and which
have ample light and space for the development of branches.
Lumber sawed from such wavy grains
knots, and
Attention
are
has
straight grain
These
desirable.
trees
usually contain
will
been called
already
purposes,
structural
trees
curls,
of great beauty.
the fact
that,
for
most readily found
are
qualities
to
and freedom from knots
growing under forest conditions
that
;
is,
among
in
other
where the effort of the growing tree to reach the light, together with a process of " natural pruning " which prevents trees,
branches from growing, results
in
the production
of
long,
straight stems.
The Adaptability of the various woods depends on a The carpenter and builder, who requires
255.
variety of conditions.
a large quantity of material with the least possible outlay of labor
upon
that are to
it,
uses those kinds that are abundant and cheap,
be had in timbers of large dimensions, that are
to ship, easy to work, fairly
stiff,
light
and insect proof. They need
not be handsome, hard, tough, or very strong, and shrinkage
wood
after the
in place
is
be
soft
and reasonably
no serious objection.
is
may be
that the material
free
it is
of material, but
In order
necessary that
The
from curls and knots.
maker uses smaller quantities
amount
worked,
easily
it
furniture
he expects to put
and he requires a wood that combines strength, and sometimes toughness, with beauty and hardness, one that takes a good polish, that is not easily a large
of labor
upon
it,
—
indented, and that will keep firm joints. it
is
required that
in place
;
it
shall neither
need not be very
or very cheap, or
abundant
large dimensions.
toughness,
wood
light, or
soft, or
insect proof,
any one kind, or furnish pieces of
The wagon maker
strength,
builder, cooper,
in
For some purposes,
warp nor shrink when
seeks the qualities of
and hardness combined
;
the
carriage
and shingle maker require straight-grained,
1
BENCH WORK
66
easy-splitting
woods,
with
IN
WOOD.
long
the
which precludes
fiber
knots; the essentials for telegraph poles are durability, elas-
and the
ticity,
good railroad must
right proportion of length
to
diameter; and
must be hard, must hold spikes
ties
and
firmly,
weather.
resist the action of the
CHARACTERISTICS OF TYPICAL TIMBERYIELDING TREES. 256.
Classification of Trees.
States nearly four
greater part of
all
hundred
— There
wood used
the
are in the United
distinct species of trees, but the
construction
in
taken
is
from a comparatively small number. Trees are divided into two general classes known as exogens and endogens.
which are
The former
up by rings or being upon the
built
includes
layers,
outside.
crease from within, the
all
trees the trunks of
— the growth,
therefore,
Endogenous
trees in-
new wood-strands being
interspersed-
among
surfaces
to
appear dotted,
Fig. 308,
which represents a cross-section
the old, and causing cross-
trunk of a palm tree.
as
of the
Old endogenous stems
have the older and harder wood near the face
and the younger and
of this class are
found
toward the center.
softer
in palms, yuccas,
the character of their growth
is
by
illustrated
sur-
Examples
and bamboos, and
well illustrated in the
common
cornstalk.
257.
The Exogens
are the timber-yielding trees,
and since
they furnish the woods useful in construction, they are the
ones of special interest to the woodworker. divided into conifers.
broad-leaved trees
Most
They
and needle-leaved
are
sub-
trees,
of the broad-leaved trees are deciduous
;
or
that
TIMBER AND
ITS
PREPARATION.
167
is, they shed their foliage in the autumn of each year. The needle-leaved trees are, almost without exception, evergreen.
Fig. L509
.
*****
.#»
m*4 258.
Effect of
Environment on
the growth of trees
as greatly influences their timber value.
is
such
Trees which grow
in
the open, quite apart from other trees, acquire a shapeliness
BENCH WORK
i68 and beauty which the
is
WOOD.
IN
never equaled by those which grow in
thicket or forest, but the timber value of such trees
decreased by the presence of limbs, which branch from
is
all
sides of the stem, leaving but a short length of clean trunk
A
from which clear lumber can be made, Fig. 309. tree,
on the other hand, finds
light only at the
which crowd
it
on every
from putting out branches until
it
finds a level
shade of the
Fig.
trees,
310
forest
The
top.
side, prevents
where
A
reach out into or over their tops. has in fact two floors, the
first
it
can
it
forest
being the
ground out of which the trunks of the trees
and the second, the
spring,
floor of .foliage
where the tops of the trees branch, and
crowd each other
for
room and
and
light,
above which the occasional tree of unusual vigor
rises
and waves
Between these from forty the
to
two
its
floors,
boughs.
lofty
a
more than eighty
distance
trunks of the trees
straight, limbless
which, like high columns, support the of foliage above.
of
extend
feet,
These
floor
smooth
straight,
trunks of the forest trees constitute the chief source of
commercial timber. Fig. 310
shows a tree of forest growth as exposed to view by the removal of neighboring
259.
trees.
Broad-Leaved Woods vary
greatly
in structure and, therefore, differ widely in
quality
and
use.
In general,
it
may be
said that they usually
contain no resins and that their density, or weight,
is
great;
they are usually hard and have a complex and irregular structure,
and
for these reasons are difficult to
work
;
and they are
likely
growth and shape, having many branches, and, therefore, not productive of large logs or blocks which to be of irregular
TIMBER AND are free from knots.
ITS
Some
PREPARATION.
1
69
with difficulty and are in
nail
other ways unsuitable for use in general construction, but are
making
better adapted to cabinetwork, the
of furniture
and
implements, and any other work which requires beauty of finish.
Ash, basswood, beech, birch, buckeye, butternut, catalpa, cherry, chestnut, elm,
gum, hackberry, hickory,
holly, locust,
maple, mulberry, sassafras, sycamore, tulipwood, and walnut
American woods
are the principal
Of
sion.
of the broad-leaved divi-
these the oak, ash, maple, beech, walnut, and pop-
probably furnish the greater part of the commercial timber
lar
which comes from trees of of an oak, tree, is
260.
shown by
Oak
more than
The
this class.
general appearance
which may be accepted as a typical hard-timber Fig. 309.
(Qttercus).
— The oaks,
forty varieties, produce
of
which there are
in all
woods which are exceed-
ingly variable, but they are usually heavy, hard, tough, porous,
very strong, and of coarse texture, the sapwood whitish, the
heartwood ranging
in color
from a
There are three well-marked kinds,
These are kept
brown.
light to a reddish
— white,
red,
and
distinct in the market, the white
live oak.
and the red
oak being the most common. 261.
oak
is
White Oak (Quercus
alba Linn.).
eastern portions of the United States. five to
— This
one hundred feet
in diameter.
The bark
the variety takes
its
in height
It
grows from seventy-
and from three
to six feet
has a grayish white color from which
name.
The annual
layers are well
and the medullary rays are broad and prominent. is
variety of
found widely distributed over the north-central and the
marked
The wood
hard and liable to check unless carefully seasoned.
durable in contact with the
soil
and
is
It is
capable of a high
used in shipbuilding, cooperage, cabinetmaking,
polish.
It is
and
the framework of buildings, as well as for furniture,
in
BENCH WORK
i/o
IN
WOOD. fuel.
The
pounds per cubic
foot.
agricultural implements, carriages, railway ties,
weight of the seasoned wood It exists in large quantities
woods
is
fifty
and
is
and
one of the most valuable
in general use.
262.
Red Oak {Que re us rubra Linn.) is found east of the Rocky Mountains
and Kansas, and
Nova
Scotia to
Massachusetts.
Georgia, reaching It is often brittle,
ture than white oak, being
its
and
is
more porous, Fi
in
Nebraska
ranges from
best development
in
usually of coarser texless durable,
and even
311
more difficult to season. The tree grows to be from ninety to one hundred feet in height, and from three to six feet in diameter, and has brownish gray bark, which is smooth on the branches. The heartwood is light brown or red, the sapwood darker, the medullary rays few and broad. For carpentry and for furniture
oak.
It is
making
it
brings about the
same price with white
used for clapboards, barrels, interior
and other work of secondary importance. five
pounds per cubic
shown by
Fig. 311.
foot.
The
Its
finish, chairs,
weight
is
forty-
distribution of the oaks
is
TIMBER AND 263.
ITS
Maple {Acer) wood
is
PREPARATION.
heavy, hard, strong,
and often wavy-grained.
of fine texture,
shrinks
brown
of light
ing, paneling, for stairways
Its color is
heartwood.
a It
mechanism
carving,
The
of pianos.
maple and the
used for ceiling,
work
finishing
for furniture.
It is
silver or
which
turnery,
scroll
name, though
it
the United States, though
The
Florida and Texas. in height It
is
tree
takes
found princi-
It is
Canada and the northern part
its
of
range extends as far south as
tree
grows from
seventy to one
and from one and one-half
the hardest variety of maple
and sometimes curly
to four feet
known and
wood is superior in quality. Dry maple weighs forty-three pounds per cubic eye, blister,
it
has various local names, as hard maple,
pally in the southern part of
in diameter.
— This
into sugar, from which fact
black maple, sugar tree, and rock maple.
hundred feet
and the
work,
white maple.
made
is
a good
principal varieties are the sugar
Sugar Maple {Acer Sac charurn Marsh.).
yields a sap
floor-
in houses,
shoe pegs, school apparatus, wood type,
lasts,
wood
tool handles,
its
It is
and other
and car construction, and
material for shoe
264.
in the
moderately, seasons, works, and stands well, wears
smooth, and takes a fine polish.
for ship
tough,
stiff,
not durable in
It is
the ground or under exposure to the weather.
creamy white with shades
I/I
Bird's-
foot.
are found
effects
its
in
this
wood. 265.
Silver or
White Maple {Acer dasycarpum Ehr.), and locally swamp maple,
also frequently called soft maple,
water maple, and river maple,
from to
Brunswick
is
found in a region extending
to Florida,
and westward intermittently
Dakota and the Indian
tics its
New
Territory.
Its
general characteris-
are similar to those of the sugar maple, though
sapwood somewhat
grade
is
somewhat
lighter in color,
and
its
inferior to that of sugar
it is
weight
softer,
less.
maple and
its
Its
use
BENCH WORK
72
IN
WOOD. White maple weighs when
extends to cheaper kinds of work.
seasoned thirty-two pounds per cubic foot.
266.
Black Walnut (.Juglans nigra Linn.).
Juglans there are two species,
known
by the name walnut.
and
as black walnut
white walnut, or butternut, though the former popularly
— Of the genus is
Black walnut
characterized is
found
in
Ontario and Florida, on the Allegheny Mountains, and west-
and
ward intermittently to Nebraska Fiir.
California. tree
Its distribution
is
Texas,
and
also
in
3 is
well
shown by
Fig. 312.
The
reaches a height of from ninety to one hundred and
twenty-five feet, and a diameter of from three to eight feet,
has
an
almost
except in
black
bark,
some portions
of
and makes a fine appearance, the West, where it is small
and low and much-branched.
It
because of the great demand.
now everywhere is The wood is heavy,
strong, rather coarse-grained, liable to
seasoned, easily worked, and soil.
Its
color
is
is
check
if
scarce
hard,
not carefully
durable in contact with the
a chocolate brown with lightish sapwood.
TIMBER AND The annual thin its
PREPARATION.
/ 5
rings are obscure, the medullary rays
numerous but
ITS
and not conspicuous.
when oak has become
Until lately,
competitor, walnut has been more generally used for gun-
stocks, for all kinds of furniture,
and
for the interior finish of
The weight
buildings than any other North American tree.
wood
the seasoned
thirty-eight
is
pounds per cubic
of
foot.
—
Yellow Poplar {Liriodendron Tulipifera Linn.). This wood is also commonly called tulip tree and white wood. 267.
It is
found in the region extending from
and westward intermittently
to
New England
to Florida,
Michigan and Mississippi.
The
grows to be from sixty to eighty feet in height and two
tree
feet or
more
in diameter, the
and the sapwood
color,
bark being smooth and of a gray
lighter.
usually light, soft,
It is
stiff
but not strong, and of fine texture, with the annual rings very
obscure and the medullary rays thin and inconspicuous.
wood
shrinks considerably
injury,
does not
tionally well.
when
split in nailing,
It is
and works under a
cars,
and
carriages,
for finishing
ships, for the side
and
tool excep-
one of the largest and most useful of the
broad-leaved trees of the United States.
and paneling,
The
drying, but seasons without
lumber
It is
used for siding
in the building of houses,
boards and panels of wagons and
manufacture of furniture, implements,
for the
machinery, wooden pumps, wooden ware, boxes, shelving, and
Large quantities of the wood are used
drawers.
facture of paper pulp.
The weight
manuwood is
in the
of the seasoned
twenty-six pounds per cubic foot.
268.
Beech (Fagus ferruginea
Ait.).
— This wood has only
one representative on the American continent, though ferent localities
beech.
It is
to Florida,
The
called red beech, white beech,
it is
found
in the region
extending from Nova Scotia
and westward intermittently
tree grows to be
from
in dif-
and ridge
to
Wisconsin and Texas.
sixty to eighty feet in height
and
BENCH WORK
174 from two
to four feet in diameter, but there
supply of the wood nor can
similar to
and
it
is
not an abundant
be obtained in pieces of very
it
Ironwood, sometimes called blue beech,
large dimensions.
wood wood
WOOD.
IN
is
sometimes confounded with
it.
is
of a reddish color with variable shades,
is
nearly white.
The
grain
is
close, the
The
and the sapannual rings
The wood
obscure, and the medullary rays conspicuous.
heavy, hard, strong, works well, and takes a good polish.
not durable in the ground,
manufacture of
mon
is
lasts,
handles, and furniture.
European countries
in
carving, carpentry, millwork, of the seasoned
wood
is
in
(sylvatica)
is
It is
used for the
The
variety
com-
wood
also used in
and wagon making.
The weight
forty-two pounds per cubic foot.
Ash (Fraxinus).
269.
merce next
in drying.
is
It is
boring
liable to the attacks of
and shrinks and checks
insects,
is
heart-
— This wood occupies
a place in
com-
In fact, ash and oak
importance to that of oak.
resemble each other in that there are bands of porous spring
wood
though the medullary rays of ash are thinner
in both,
and are often hardly discernible. States,
Ash
but easier to work than oak.
tractive,
about fifteen species of
ever, separate
them
into white
is
coarser and less at-
There
this genus.
and black
are, in the
United
Lumbermen, how-
ash.
White Ash (Fraxinus Americana Linn.) grows in the Nova Scotia and Florida, and westward intermittently to Minnesota and Texas. The tree rises to a height 270.
region between
of
from
forty-five to ninety feet
diameter.
It usually
and
is
three or four feet in
has gray or dark brown, furrowed bark, and
The
smooth
leaves,
wood
a mottled, reddish brown, and the sapwood either white
is
which are white on the under
side.
heart-
or very light.
The wood
is
straight-grained, heavy, hard, strong,
tough, but becomes brittle with age
with the
soil,
;
it is
stiff,
and
not durable in contact
shrinks moderately, seasons .with
little
injury,
TIMBER AND takes a good polish, and
is
PREPARATION.
ITS
easily
worked.
75
In carpentry
used for finishing lumber, for stairways, and for panels. baskets, cars, tool handles, as wagons, carriages,
of furniture.
and hoops are made from
most useful of the broad-leaved seasoned wood
is
it,
farm implements, machinery, and
This wood grows in abundance and
thirty-nine
varieties.
is
it
is
Barrels, as well
kinds
all
one of the
The weight of the foot. The general
pounds per cubic
Fis-
313
IVhiteAsk
Big Tree
Redwood
characteristics of the other varieties of this genus are very similar to those of white ash.
The
wood
distribution of this
is
shown
by Fig. 313. 271. eral
Needle-Leaved Woods are more uniform
characteristics
than
the broad-leaved
in their gen-
varieties.
These
characteristics are lightness, regularity of structure, obscurity of the medullary rays, presence of resins, absence of pores in
sections,
and the ease with which the wood
of this class
may commonly be
identified
is
worked.
Trees
by the cones, by the
BENCH WORK
I76
WOOD.
IN
needle-like leaves, and by the fact that they are evergreen,
although there are a few exceptions to this characterization.
In
common
speech, needle-leaved tree, soft wood, conifer, and
evergreen are used as synonymous terms. large, straight pieces of
for carpentry
and the frames
The
and
of buildings,
lumber
States they furnish the bulk of struction.
These
trees afford
timber and, consequently, are suitable in the
United
purposes of con-
for
principal varieties are cedar, cypress,
hem-
fir,
and yew. The general
lock, tamarack, pine, redwood, spruce,
appearance of a needle-leaved tree of forest growth
shown
is
by Fig. 310. 272.
Pine (Pinus)
may be varieties loblolly
is
by
far the
which
varieties, all of
classed as either hard pine or soft pine.
The
four
— white and long-leaved short-leaved pine — are important lumber the production pine,
pine,
pine,
Of
these, white pine
the other three are hard woods.
and
long, smooth, straight,
for
of
in
building purposes.
273.
most important of the
There are several
needle-leaved family.
is
a soft wood, while
Pines are characterized by
solid trunks.
White Pine {Pinus Strobus
Linn.)
is
found
in
the
north-central and northeastern United States, advancing north-
ward into Canada, southward into white pine, soft pine, is
is
known
Illinois,
and along the
Alle-
This species, though commonly called
ghenies into Georgia.
in different localities as
Weymouth
pine,
northern pine, spruce pine, and pumpkin pine.
distinctively a northern tree,
portions of the South.
one hundred and in diameter,
fifty
It
though
is
larger.
and from three
The wood
is
It
found in some
grows to be from seventy-five
feet in height,
and even
it
very
to
to six feet soft, light,
not strong, very close, straight-grained, exceedingly easy to
work, and susceptible of a beautiful polish. sages are small
The
and not numerous or conspicuous
;
resin pas-
the annual
TIMBER AND rings are obscure, Its color
is
sapwood
is
PREPARATION.
ITS
177
and the medullary rays thin and numerous.
a very light brown, often tinged with red, and the
nearly white.
when
other pines
drying,
seasons well, shrinks less than
It
and
is
cabinetmaking, for interior
fairly durable.
It
wooden ware, and
the manufacture of matches,
finish,
and
used in
is
shingles, in
in carpentry,
and
most valuable building material of the northern states. existed in extensive
diminishing and
The
place.
weight of the seasoned white pine
many
has
United states
and yellow pine, and
as hard pine
States,
other names.
its
twenty-four Fig. 314.
Mill.)
is
also
in different local-
in the south-Atlantic
and intermittently from Virginia
to
principal lumber tree of the Southeast. fifty to
rapidly
a native of the southern
It is
growing freely
is
shown by
Its distribution is
Long-Leaved Pine {Finns palustris
274.
ities
foot.
now
is
the
has
some extent taking
the yellow pines are to
pounds per cubic
known
but the supply
forests,
is
It
and Gulf
Alabama, and It
is
the
grows to be from
ninety feet in height and from one to three feet in
diameter.
Its distribution is
The annual
shown by
Fig. 314.
rings are easily detected, the medullary rays are
numerous and conspicuous, and the color
is
with the sapwood thin and nearly white.
light red or orange,
The wood
is
heavy,
very hard, very strong, tough, coarse-grained, and durable,
and
is
used for fencing, railway
exterior finishing,
the United pitch, tar, it
is
and
shipbuilding, interior
and
heavy construction.
In
States almost the entire product of turpentine,
and
resin
comes from
considered the most
The weight
ties,
for all sorts of
of the seasoned
this species.
Commercially
valuable of the southern pines.
wood
is
thirty-eight
pounds per
cubic foot.
275.
Short-Leaved Pine {Pinus echinata
yellow pine and hard pine, and has
many
Mill.)
is
called
other local names.
i
BENCH WORK
78
It is
found
in the region
and Texas.
sas
The
WOOD.
IN
from Connecticut westward to Kangrows from
tree
to
fifty
sixty feet
height and from two to four feet in diameter, and of fine appearance.
Its
general characteristics are
those of the long-leaved pine, except that strong,
and
its
wood
is
thirty-two
same region
like
so
The weight
— This
as the long-leaved pine
Fig.
much
and not
pounds per cubic
Loblolly Pine (Finns Taeda Linn.).
in nearly the
lighter
uses, also, are practically the same.
of the seasoned
276.
it is
in
erect and
is
foot.
tree grows
and appears
r^i-t
WliitePine
LongleaforYellowPine Bull orYellowPine
naturally that
the to
on land which has been
which has been occupied by a
name
of old-field pine.
one hundred
diameter.
The
feet in height
abandoned, preferably
forest.
tree
This
trait gives it
grows to be from
and from two
fifty
to four feet in
In color, grain, structural qualities of wood, and
representative uses
it
is
very similar to the long-leaved pine,
TIMBER AND though
it
one of
its
is
PREPARATION.
ITS
not so durable in the natural
uses
is
79
At present
state.
making bridge timbers and
in
1
railroad cross-
In such service, by the application of some preservative,
ties.
often
it is
made to take the place of the more durable longThe weight of the seasoned wood is thirty-three
leaved pine.
pounds per cubic
foot.
Bull Pine {Pinus ponderosa Douglas).
277. of pine
is
— This
from the other yellow pines
distinct
species
in that
it is
a
product of the western part of the United States, being found
from the Rocky Mountains westward Its distribution is
of pine
shown by
known, growing
to
Fig. 314.
six
and
numerous but rather obscure;
wood
to
heartwood
is
large, the
much sapwood,
fuel.
Its
is
varies
heavy, hard,
The medullary
rays
proportion of
sap-
used in exposed places
by treating
manufactured into lumber and
and
the
it is
Since this species contains
not durable, but
in contact with the soil
It is
ties
it is
hun-
former being almost white in
color and the latter a light red.
and
The wood
value, but in general
and rather fine-grained.
strong, brittle,
are
to three
to eight feet in diameter.
thick and deeply furrowed.
is
greatly in quality
the largest species
be from one hundred
dred feet in height and from
The bark
the Pacific Ocean.
to It is
is
weight when seasoned
it
with a preservative.
also used for railway is
twenty-nine pounds
per cubic foot.
278.
United all
The Spruces (JPicea) are found in abundance in and though there are several varieties, they
States,
divided commercially into two classes,
black spruce.
Spruce resembles white
characteristics
and uses
that there It is
is
much
;
in fact, the
the are
— white spruce and
pine
in
many
resemblance
is
confusion of names in different
of
its
so great localities.
often very hard to distinguish between black spruce and
white spruce.
BENCH WORK
l8o
WOOD.
Picea Ma?'iana Black Spruce (Picea nigra Link tree grows in a region between Pennsylvania and
279. Mill.).
IN
;
—This
Minnesota, and along the Allegheny Mountains to North Carolina,
to
but reaches
its
best development in Canada.
a height of from forty
from one
two
to
feet,
and
The wood
satiny.
.
is
light, soft,
has a light red color which
piles, posts,
somewhat
and railway
wood
is
It is
States,
used in shipbuilding, and for
{Picea alba Link; is
found
Canada, Labrador, and Alaska.
and use are much the same
except that the trees grow a
wood and
is
little
somewhat
is
Hemlock
281. species,
foliage
The heartwood
In fact, in most of
ties.
not strong,
sometimes nearly white, the
grows in high latitudes and
Mill.)
of
its
uses
it is
The weight
a of
twenty-eight pounds per cubic foot.
White Spruce
280.
is
inferior substitute for white pine.
the seasoned
istics
whiter.
still
grows
contains considerable resin
It
the medullary rays are few but conspicuous.
sapwood being
It
and a diameter
usually having a straight, conical-shaped
trunk and dark foliage. straight-grained,
to eighty feet,
Its
Picea Canadensis in
northern United
general character-
as those of the black spruce,
higher and the color of the
lighter.
(Tsuga), of which there are two principal
light, soft, stiff, brittle,
coarse-grained, and inclined
sapwood and heartwood are not well denned. The wood has a reddish gray color, is free from resin ducts, is moderately durable, shrinks and warps considerably, wears rough, and retains nails firmly. The bark, which to splinter,
is
and the
limits of
red on the outside,
282.
is
used for tanning leather.
Eastern Hemlock (Tsuga Canadensis Carr.)
is
found
and central Canada, where it has its best development, and extends southward to North Carolina and Tennessee. It is a handsome tree with a straight trunk, and grows to be
in eastern
eighty or
more
feet in height
and two or three
feet in diameter.
TIMBER AND It
PREPARATION.
ITS
manufactured into coarse lumber and
is
frames of buildings, for outside
This species furnishes nearly
The weight
market.
all
of the
of the seasoned
is
and
finish,
is
used in
the
for railway ties.
hemlock
wood
l8l
for the eastern
twenty-six pounds
per cubic foot.
283.
Western Hemlock {Tsuga Mertensiana
Carr.), grow-
ing in the western part of the United States and Canada, and also in Alaska,
larger trees,
is
is
similar to eastern
of a better quality,
hemlock but appears
and
heavier,
is
being about thirty pounds per cubic foot. prevent decay,
it
contact with the
284. in
is
much used
soil,
in
When
its
in
weight
treated to
exposed situations and in
especially for railway ties.
Bald Cypress {Taxodium distichum Rich.) is found in the south- Atlantic and Gulf states, through
Maryland,
Florida to Texas, and in the Mississippi valley from southern Gulf.
to the
sometimes forming large
soft,
close,
swamps and wet The wood is light,
usually grows in
Illinois
places,
It
forests.
straight-grained, not strong, resinous, very easily
worked, and very durable when in contact with the water
;
soil
or with
the medullary rays are numerous but very obscure.
It
has a color between light and dark brown with nearly white sap-
wood.
It is
manufactured into shingles, and
struction of buildings in
contact with water
tanks, casks, is
and
and
for railway ties.
fits it
barrels.
is
used for the con-
Its peculiar durability
for use also in the
This wood
is
manufacture of
a very important one
;
it
commercially divided into white and black cypress because of
differences in hardness due to age of the seasoned
285.
found
wood
is
and environment. The weight
twenty-nine pounds per cubic foot.
The Common Redwood {Sequoia scmpervirens in the central
and northern coast region
Endl.),
of California,
grows to be from two hundred to three hundred feet in height,
and from
six to eight,
and sometimes
to twenty, feet in diameter.
1
BENCH WORK
82
When young
it
is
WOOD.
IN
a graceful tree with straight and tapering
trunk and drooping branches, the lower ones sweeping the
In old age the trunk rises to a great height bare of
ground.
boughs, and the branches on the upper part are short and irreg-
The wood resembles
ular.
that of cedar in appearance, the
sapwood almost white,
color being a clear, light red, with the
the proportion of sapwood to heartwood being small.. light,
soft,
not
very
strong,
The medullary
obscure. is
rays are
fins,
flumes, tanks for water
When
and its
286. Torr.)
wood
is
it
forms a good
The weight
twenty-six pounds per cubic foot.
The Big-Tree Variety is
curled
and cabinet work.
material for interior decoration of the seasoned
is
of
Redwood {Sequoia
the largest tree of the American forest.
same
in practically the
and
ties, cof-
and water
for tanning purposes,
grain
in con-
Pacific coast
used for shingles, fence posts, telegraph poles, railway
pipes for irrigation.
is
numerous but very
lumber of the
It yields the principal
It
coarse-grained,
and very durable
susceptible of polish, easily worked, tact with the soil.
rather
brittle,
locality as the
common
gigantea It
grows
redwood, but
appears chiefly in isolated groups, and there are probably only
Some specimens
a few hundred individual trees in existence.
have been measured that were three hundred and twenty feet height and thirty-five feet in diameter, with bark about
in
two feet thick.
The wood resembles
redwood except that redwoods
is
it is
shown by
more
that
The
brittle.
of
common
the
distribution of the
Fig. 313.
LOGGING. 287.
"Felling Timber
1
should
practiced at the period of maturity
not have acquired 1
its
always, ;
if
greatest strength
Quotation marks refer to Thurston's
if
possible,
earlier, the
and
will
and
will
density,
" Materials of
be
wood
Engineering."
TIMBER AND
ITS
PREPARATION.
contain too great a proportion of sapwood will
oak
the wood The age at trees. The
have become weakened by incipient decay."
which maturity is
said to
and
old,
reached varies with different
is
come
to maturity
when about one hundred
should not be felled at
it
less
83
later,
if
;
1
than
years
" Pine
sixty.
timber should be cut at from seventy to one hundred years of
and ash and elm
age,
at fifty to
one hundred."
In practice,
however, trees are often cut before their age of maturity,
it
being not uncommon, in dealing with a forest growth, either to clear the
ground of
from time
As opposed
marketable.
whether large or small, or to
all trees,
to time all trees
which are of
to this
sufficient size
custom, a modern theory of
many
forestry favors a division of the forest tract into
which may be cut each
certain of that
when
will
have elapsed to permit the
parts,
year, the plan being such
the last subdivision has been cut, sufficient time first
to
reforested, and, therefore, ready to give
An
cull
to be
become completely
up
its
second growth.
alternative plan, applying especially to forests of
mixed
growth, provides for the systematic removal of mature trees only, the
work being done under
these
be
methods the
made
to yield a certain revenue
development
of
series of years,
has been
made
either of
may The complete
products of the
each year.
soil,
any such plan necessarily involves a long
and ;
By
careful supervision.
forest, like other
but
no great progress seems probable that the large govern-
as yet, in this country, it
ment forest reservations will hereafter be managed by some method of this kind. " The season of the year best adapted to felling timber is either midwinter or
midsummer.
August are often selected, as can be green
easily distinguished,
while the
unsound
The months
of
at those seasons the
July and
sound trees
from the fact that they remain trees
are
then
turning
yellow.
Healthy trees then have tops in full foliage, and the bark is uniform in color, while unsound trees are irregularly covered
BENCH WORK
I84
WOOD.
IN
with leaves of varying color, having a rougher and often a
loosened bark, and decaying limbs." should be immediately stripped of
wood only
After felling, "the trunk
its
bark,
and when
heart-
wanted, the sapwood removed as soon as possible."
is
This gives the wood a chance to dry quickly and at the same time prevents deterioration by the action of worms and decay. "
The bark
removed from trees in spring and the autumn or winter." This, ordinarily, can
often
is
felling deferred
till
be done only with small
when
trees,
but
it is
a good course to pursue
possible.
In the actual felling of the trees, the method has been from
time immemorial to use the ax, and very small trees are cut in this
way
;
for larger trees the
tion with the ax.
The
cut
is
usually
saw
is
still
used in connec-
made high enough above
and in some cases the accumulation of pitch at the base of the tree. For large trees this height is from six to eight feet above the ground. Notches are first cut on opposite sides of the tree, into which are inserted boards on which the workmen stand. After the direction of the fall is decided, an "undercut" is made with the ax at right angles to it and on the side next the ground to avoid the very hard grain, the heavy sap,
to the
fall,
third of side,
its
extending into the tree a distance equal to onediameter.
The saw
is
then applied to the opposite
and when the kerf has been advanced nearly through
to
the undercut, wedges are driven into the saw-cut so as to
bring the tree possibility
of
down
in
the proper place.
doing injury to other trees
Machines have been invented
this
way the
may be
avoided.
In
to take the place of the
method
described, but they are not in general use.
After the tree has been felled length.
it is
sawed into logs of suitable
Barkers then chop or strip away the bark, either from
the whole surface of the logs or from the side on which they
and clear away the underbrush way along which they may be moved. are to be dragged,
to
form a
TIMBER AND
Transportation of the logs
288.
rounding conditions.
In
practice
to
is
and
sur-
large
must be handled, the
trees
drag the logs by means of horses or
stream or railroad.
nearest
to the
effected
is
locality
85
regions except the West, where
all
redwood and other very
common
1
to the sawmill
which depend upon the
in different ways,
oxen
PREPARATION.
ITS
For
tramways are made by placing logs of similar
purpose
this
size parallel to
each other across the way, at intervals of from four to eight
The
feet.
logs are
where they have or
if
moved
fallen,
the ground
tramway from the places
to the
by rolling
the distance
if
otherwise,
;
A number
they are pulled into position by a horse.
logs
of
then fastened together by chains and a team of horses
are
or oxen drags
them along the tramway, which leads
logging railroad or to a stream or pond. logs are placed within the high-water
water
is
low,
either to a
In the latter case the
zone
at a time
when
and when the spring freshets cause them
they are guided to the sawmill, which
This
or stream.
transportation. in
very short,
is
inclined in the proper direction
is
Canada, the
is
usually built near a
pond
common method
the cheapest and most
is
the
to float
of
In the northern part of the United States and
common
practice has been to carry on the log-
ging in the winter time, and in the spring to
float the logs
on
the water courses to the mill, which does not run during the
winter season. is
made by
ing water
over
it
Here, instead of a tramway, an "ice run"
cutting a shallow trench in the ground and pour-
upon
When
it.
by a team.
it
is
frozen, the logs are dragged
This forms an
tion.
The methods here described
eastern part of the United States,
and compared
efficient,
with the tramway a very inexpensive,
means
and
where the operations are not extensive.
in
of transporta-
common
in the
fact in all
places
are those
In the West, where
bulky material must be handled, and the work a large scale,
moving the
the
logs.
tendency
is
to
rely
is pursued upon upon machinery for
Chains are secured to them by means of
BENCH WORK
86
1
WOOD.
IN
grappling hooks, and they are drawn from the place of
fall to
the
tramway, or " skid-road," by the action of a " yarding " engine,
which
is
form to engines used in hoisting
similar in
tramway another engine water way.
may be
slid
all
usually situated
upon
order that they
may be
The
the shore of easily
mounted upon a
carriage,
advancing toward the saw ing after the cut
is
effected by
which the log
which
is
is
fed.
means
The
log
arranged to reciprocate,
and return-
Various means are employed for
propelling the carriage, which in a large mill
The two
with great rapidity.
are
or pond, in
reached from the lumber camp.
for the cutting stroke
made.
is
stated, they
some stream
process of making lumber from logs
of a saw, fixed in position, to is
side, the logs
machinery necessary for
the
As has been
converting logs into lumber.
on the
;
to the nearest railroad or
Where the course is down a mountain down a suitably constructed chute.
Sawmills contain
289.
them
pulls
classes of
is
made
move
to
machinery used
in
general sawmilling are the circular sawmill and the band saw-
The former
mill.
is
the older and, for general purposes,
more used. The objections width of loss in
of
its kerf,
to the circular
saw
which causes a great waste
arise
is still
from the
of material, the
sawdust for some cuts being one-fifth the whole amount
wood used. The band saw
much
has
reduced width of the
kerf,
to
recommend
it,
which, ordinarily,
especially in the is
but
little
more
than half that of a circular saw of the same power and capacity hence, the amount of material wasted in the form of sawdust less.
The band saw
the circular saw,
is
and
;
is
more expensive and not so portable as therefore more suitable for large and
is
permanent establishments.
—
The log is drawn from the The Process of Sawing. pond by means of a carrier, or log jack, operated by the power of the mill. Arriving at the proper point, by suitable 290.
mill
TIMBER AND
PREPARATION.
ITS
1
87
mechanism the log is rolled upon skids in a position near the and then by the movement of a single lever is thrown upon the carriage and fastened. As the carriage goes forward carriage,
toward the saw, the
first
return of the carriage,
by an amount log
to
is
cut.
move
it
On
the
sidewise
sufficient to allow the log to clear the saw.
The
turned a quarter of a revolution, after which another
is
slab
outside piece, or slab,
mechanism operates
In this way four slabs are taken
cut.
is
leaving the
off,
log nearly square in section, though the thickness of the slabs is
not sufficient to allow the meeting of the plane surfaces pro-
duced by
their"
removal.
planks or boards.
From
which carry them
rolls,
trimmed
The squared
log
is
then sawed into
the carriage, these land on revolving to
the " edger," in which they
are
so as to give the widest possible planks with parallel
edges. From the edger, the lumber moves on rollers or chain conveyors to the " trimmer," where it is made to pass saws
which are
set to cut the pieces to standard lengths.
thrown on a platform, from which
it is
It is
then
trucked to the yards for
storage or to the cars for shipment.
When
the slabs leave the saw they are conveyed by revolv-
ing rolls to the "slasher"; in this machine they are cut into lengths, usually of four feet,
sawed up into are sorted
laths,
conveyed
to
the lath machine,
and bound into bundles.
by hand, and some go
the
to
All short pieces
shingle machine,
while the rest are converted into stove wood.
and
fine
coarse stuff that cannot be used, even for fuel, get
it
291.
is
Milling.
— The processes mill, in
and the
burned
to
of the sawmill are followed
which the rough-sawed lum-
planed to a smooth surface and
molded, to make inside
is
out of the way.
by those of the finishing ber
The sawdust
refuse help feed the furnaces of the mill,
finish.
it
is
matched, beaded, or
serviceable for floors, wainscoting, and
Because
of
the
prominence
of
the
planing
BENCH WORK
155
machine
in these mills, such establishments are often called
planing
Planing mills
mills.
mills, or located at
lighter
and
may be combined
with the saw-
any convenient point between them and
the centers where lumber is
WOOD.
IN
consumed.
is
As finished lumber
bulky than the rough-sawed, the operation
less
of a finishing mill in connection with the sawmill effects a
saving in freight
when
the lumber
On
shipped.
is
the other
hand, as the planing mill usually deals with seasoned lumber,
and
as better
judgment as
can be exercised when
to finishing
the exact nature of the requirements
known,
is
often most
it is
convenient to have the finishing mill at the point of consumption.
It is for this
which are
reason that planing mills are located in cities
from sawmills.
far distant
The machines
of the finishing mill are
numerous.
are planers which dress the rough plank to a
and
to a uniform thickness
;
There
smooth surface
matching machines which cut
the tongue and groove on the edges be used for flooring and similar work
which are to
of boards
molding machines for
;
giving finish to the edges of planks or for producing strips of
curved section
and a variety
;
saws for ripping and saws for cross-cutting,
of other
and more highly specialized machines,
such as those for boring, paneling, and sand-papering. description of these does not
fall
discussion, but such machinery
is
so
common
Water
composed
in Timber.
with reference to the
life
may occur
of the tree.
and
all cells
lifeless cells, fibers,
;
These contain more or
in three conditions: (1)
and
and
stu-
action.
its
(3)
it
vessels.
partly
is
of different functions
greater part of the contents of the living cells
the walls of
full
— As has been explained, wood
of cells of different forms
water, which
most
that
dents can easily gain an opportunity to inspect
292.
A
within the purpose of this
fills
;
it
(2)
it
less
forms the saturates
the cavities of the
In some cases the water in
growing timber makes more than half the weight of the wood.
TIMBER AND
ITS
PREPARATION.
Sapvvood contains more water than heartvvood is
more water
upper portion of a
in the
1
;
89
hence there
tree trunk than in
its
lower portion, more in limbs than in trunk, and most in the Different trees of the
roots.
same kind
amount more than stunted
differ in the
of water they contain, thrifty trees having
ones,
the
and young ones more than
wood
the moisture in
old, while
The summer than in recently made by
of all trees varies with the season of the year.
popular idea that trees contain more water in winter, however,
is
not always correct, tests
the United States Bureau of Forestry showing that the greatest
weight of certain trees
The Process
293.
in the winter.
is
of
Seasoning consists
green wood, either by natural or
artificial
in driving out of
means, a consider-
able portion of the water contained in the walls and cavities of
its cells.
Seasoning thins the walls of the
wood appear more porous. The son, or dry, depends upon the kind
the
the part of
piece,
the character of
rate at
taken, and
is
it
exposure to drying influences
its
will sea-
it
of timber, the size of the
trunk from which
the
and makes
cells
which
pine, for
;
example, dries faster than oak, .small boards faster than large ones,
and sapwood
Wood
faster than
heartwood.
newly cut from a living
tree,
when exposed
to ordi-
nary atmospheric conditions, gradually dries, and in so doing
changes is
its
weight and dimensions.
Green lumber,
unstable with reference to these qualities and
able for
many purposes
until
it
is
has been seasoned.
therefore,
not serviceAll
lumber
designed for the manufacture of furniture, cabinetwork, and
machinery should be thoroughly seasoned before
The method employed timber
will
during the
in seasoning
it is
used.
must be such that the
not only dry, but will also be preserved from injury process.
Some
of
the
harmful
effects
due
to
improper ways of seasoning are the formation of cracks, or " checking," and a loss of strength caused by injury to the
wood
structure
;
these must be taken into account in deciding
BENCH WORK
190
upon the method
to
WOOD.
IN
Those most common are
be used.
seasoning, steam seasoning, water seasoning, boiling in
air oil,
and kiln-drying. 294. Air Seasoning
is
the cheapest and probably the best of
the methods mentioned, although it is slow and must be carefully conducted or there will be much injury by decay and by 3^i»;.
checking. the air
It consists in piling the
may
circulate freely about
the moisture
is
is
then regarded as seasoned.
without proper air spaces, if
Under
it.
become incapable
the exercise of considerable care.
other hand,
lumber out
of doors
where
these conditions
given off and the solid constituents of the sap
gradually harden and
the lumber
315
it
is
If
sure to
of further
change;
Air drying
demands
green lumber
is
piled
decay; while, on the
exposed to sun and wind, the moisture in the
outer portions of each piece thus exposed evaporates faster
TIMBER AND
PREPARATION.
ITS
I9I
than that in the inner portions, and that in the ends faster than that at the middle, with the result that shrinkage proceeds
Both decay and checking
unequally and cracks are formed.
may be prevented by ing air
it
from the sun and
may
also
piling the timber properly rain.
may be
on
all
sides of the piles but
Fig. 315 shows a pile of railroad ties
Sawed lumber may be
as arranged for seasoning. similar way,
and with material
lumber depends upon the
being allowed
for large
piled in a
of uniform dimensions the pile
carried to a considerable height.
to air-dry
and protect-
should be so placed that the
circulate freely, not only
about each piece.
time
It
The time required
size of the pieces, a longer
than for smaller ones.
sticks
Sometimes lumber which has been piled but a few months regarded as seasoned, and for some purposes used, but the drying
from two
only partial.
is
season boards quickly, or
wood
in
ing process
employed when
is
when
it
is
it
is
it,
As
to
to soften as,
for
a season-
objectionable, because the high temperature
wood
structure to such an extent
The process con-
exposing the wood to an atmosphere of steam under
and dissolves the is
desired
is
bending
and furniture making.
likely to injure the
considerable pressure.
water
it
becomes necessary
as to decrease the strength of the material. sists in
is
safely
For complete air-dryieg
large pieces for the purpose of
instance, in shipbuilding
required
may be
to four years are required.
Steam Drying
295.
it
The steam
wood when the seasoned. The soften-
enters the cells of the
sap, leaving water in its place
dried out, the
wood
is left
well
;
ing of the fibers by the steam during this process, and the
uniform conditions of heat overcome checking, which
is
all
tendency toward
so likely to occur in air seasoning.
The
steaming process occupies but a few hours. 296.
Water Seasoning
is
accomplished by allowing the tim-
ber to remain for a considerable time in water.
Bv
this
means
BENCH WORK
I92 the sap
is
dissolved away and replaced by water, which evapo-
rates rapidly
soned
WOOD.
IN
in this
when the timber is piled for drying. Timber seaway usually shrinks uniformly, exhibiting but slight Logs which are designed for the spars of
disposition to check.
They are usually stored many months, and are thus kept and workable condition until such time as they may
ships are invariably water-seasoned. in water, with the bark on, for in a soft
be removed for finishing.
297.
Kiln Drying
is
It requires far less
ing.
a
common method
of artificial season-
time than the processes already men-
tioned, and, with the exception of air-drying,
which most lumber
subjected.
is
connection with nearly
all
which consume
wood, such as furniture and car
large quantities of
Air-seasoned lumber, designed for inside is
moisture which
298.
the one to
sawmills and planing mills, and
also with those manufacturing establishments
at the sawmill
is
Dry-kilns are to be found in
factories.
when received
finish,
often piled for a few days in the kiln to remove it
may have gathered from which there are
Kilns, of
the atmosphere.
many
forms, are large
structures fitted with machinery for circulating dry, hot air
about the lumber that
upon
light trucks,
track.
is
placed in them.
The doors
are then closed and steam
the coils of pipe by which the air air
in
escapes through a chimney and
below the pipes.
duced into that end heated
air
is
The lumber
is
which are run into the kiln upon
is is
is
turned into
Moisture-laden
heated.
replaced by dry air taken
In operation, the green lumber of the kiln
piled
lines of
is
intro-
from which the moist and
discharged, and cars containing the seasoned
lumber are removed from the other.
By
this
arrangement the
cars progress through the kiln, the dryest air
coming
in con-
is
most heavily
laden with moisture, with the greenest lumber.
This course
tact with the dryest lumber,
and that which
TIMBER AND
PREPARATION.
ITS
93
1
prevents too great rapidity in the process of seasoning.
For
seasoning green lumber, kilns require about one week for each
one-inch thickness of material. for inside work,
and designed avoid
Lumber seasoned by
chance of further shrinkage,
all
if
placed in the kiln from In general, more
forty to sixty hours for each inch in thickness.
time
is
air-drying,
can be made sufficiently dry to
required for hard woods than for
soft,
and, usually, the
former must be seasoned at lower temperatures than those which
may be employed is
with the
In any case, the temperature
latter.
limited by the tendency of the
drying process
is
Shrinkage
299.
check
to
in
timber occurs whenever
In the process of seasoning, shrinkage
ture.
width and thickness of a timber effect
little
that
wood
it
on
its
the
loses mois-
per cent, but
fully eight
Wood
length.
it
may reduce it
the
has
cannot be seasoned so well
It also
has a tendency to shrink after having
surface removed, as in finishing by use of a plane. to the
if
not shrink whenever the surrounding dryness
will
increased.
for
;
forced too rapidly, the lumber will be injured.
reopening of the pores, which
surface had
This
is
is
its
due
the fibers of the old
in
become closed by contraction
;
in this
way new
passages are furnished for the escape of moisture.
Swelling occurs in timber whenever it absorbs moisMost woods give up moisture more readily than they therefore, a timber is less likely to swell when receive it transferred from a dry atmosphere to a moist one than to 300.
ture.
;
shrink
when
the conditions are reversed.
A
slight variation,
however, in the amount of surrounding moisture. to
produce a perceptible change
of
wood.
Paint upon
all
against such changes, but
them.
As a
shrinks
and
it
will
a
is
sufficient
dimensions of a piece
exposed surfaces
rule, the softer
swells.
in the
is
some protection
not serve entirely to suppress
wood
is,
the
more
readily
it
BENCH WORK
194 301.
Warping
in
wood
is
WOOD.
IN
a change of form resulting from
unequal shrinkage or swelling.
In Fig. 316, which represents
the end of a log,
that, besides the lines defining
it
be seen
will
the annual rings, there are others extending outward from the
center in
all
directions
these have already been defined as
;
In some woods they are hardly discernible
medullary rays.
in others they distinctly
mark the
;
cross-section of the timber,
and they are not very much shortened by shrinkage.
In the
bond between the rays and the wood next them becomes weakened, and therefore, as shrink-
process of seasoning, the fibers
age occurs along the circumference of the annual rings, there is
a tendency to cleavage
Fig.
316
on
lines at right angles to the rings,
Fig.
317
Fig.
318
3 —
naturally the lines of least resistance,
If
the seasoning
the tendency
is
is
carefully done,
always apparent.
i.e.
the medullary rays.
no checks
will
For example,
if
appear, but
a log
is
cut
longitudinally into five pieces, the middle piece will, by the
contraction of the annual rings in shrinkage, at the edges than at the center, as
shown by
become
thinner
Fig. 317.
The
other four pieces will warp as shown, the surface of each piece
which in the log was nearest the center becoming the convex side after shrinkage.
according to
its
The shrinkage
of a square joist will vary
position in the log relative to the heart, as
indicated by Fig. 318.
Thus
it
will
be seen that in the cross-
section of a timber, changes resulting from shrinkage can be foretold
whenever the character
determined.
of
the
end grain can be
TIMBER AND Timbers
warp
also
PREPARATION.
ITS
1
95
When
in the direction of their length.
not due to the subjection of one part to dryness or dampness,
can be traced to uneven-
to the exclusion of other parts, this
ness in the grain, which exposes a greater
ends
in
one part of a surface than
in another.
number of The more
fiber fiber
ends there are on a surface, the more readily moisture pass will
into
out of the wood, and
or
be the local shrinkage or swelling, and consequent warp-
For example, suppose Fig. 319
ing.
.
shown.
Fig.
.
Moisture
will
escape
most readily from the surfaces r — marked A and A'. The con- —^ traction of the surfaces will force the
The most
line.
exposure.
while the other
not
from the ground are after a time
due
.
__ _'_ __ .
_
^»
z'--—~~
-
B
A
cause of warping, however,
;
Heat from a
common
all its
is
may be exposed
unequal
to the sun
the side exposed will be found concave
both in length and breadth.
newly planed on
A
—^-^-^-^= ^"" "" "^ ~~
- -
and
side of a board is
319
B
board into the shape shown by the dotted
fruitful
One
A
edge of
to represent the
a board having the grain as
A'
will
more pronounced
the
faces
stove or
causes of warping. is
left flat
be found concave in
its
to the greater exposure of the
dampness
If
a board
on the bench,
will
it
—a
upper surface,
result
upper surface as compared
with the lower, which remained in contact with the bench.
A
piece which has reasonably straight grain, and which has
been planed
all
should
over,
be
left
on
edge or end.
its
Pieces of irregular form, that are required to be
made
into
shape accurately, are best prepared when roughly cut nearly to the required dimensions, and allowed ample time warp before being finished exactly to size.
302. fungi,
Decay in Wood
which send down
tions into the
is
to shrink
caused by the growth upon
little
food-seeking threads in
wood, consuming the
cell walls
and
all
and
it
of
direc-
their contents,
BENCH WORK
I96
WOOD.
IN
and thus producing a disintegration and change which
organic food materials, heat, and abundance of
must have
air,
moisture
the moisture must not
;
live for
killed
want
and
of oxygen.
is
its
certain
amount
excludes the
checked by cold and
is
F., as well as
rot, especially
if
it
by the applica-
Perfectly seasoned
chemicals to the wood.
not likely to
immersion, how-
to
and the fungi cannot
air
Fungus growth
by temperatures above 150
tion of
wood
much water
too
ever., for
of structure
In order to grow, the fungi
called rot, or decay.
is
has good ventilation
surfaces of contact are well protected.
Timber Preservation is effected by filling the pores some fluid which destroys and prevents fungus growth, and thus protects the wood from decay. Some woods, such as oak, resist the attacks of fungi, and therefore do not rot quickly even under unfavorable conditions. For this reason, only woods of this kind were formerly used in work which was exposed to moisture, as railway ties, bridge timbers, and fence posts. Of late, however, such timber has become very scarce and costly, and much attention is now given to artificial methods of preservation which will give durability to cheaper and otherwise inferior timber. By " inferior timber " is meant those soft, porous woods 303.
with
which are especially
By
liable to decay.
treating with a pre-
servative, however, they are rendered durable,
thus be fir,
made
to take the place of white oak,
and hemlock may be used
ance to decay
is
and red oak may and
for pine in places
the chief requirement.
The
loblolly pine,
where
ment never increases the strength of a timber or its to abrasion, but, on the contrary, slightly weakens it purposes, however, the ultimate strength of timber
importance than preserving fluid of fungi, sote,
and
its is
durability.
that
it
will
The
resist-
preservative treatresistance for
;
is
many
of far less
requisite property of the
destroy and prevent the growth
for this purpose corrosive sublimate, tar
and zinc chloral are most used.
oil,
creo-
TIMBER AND
of
The manner wood to be
tive
may be
into
it.
first
vvfth a brush,
is
to
step, the
equipped fill
small, the preserva-
is
wood may be dipped
or the
lumber are
to
be treated, exten-
The purpose
doing the work.
for
the pores of the
wood
the
ties of
wood with
the fluid.
in
As a
wood must be thoroughly seasoned in order that may be as high as possible. If
is
absolutely dry,
it
will take
up considerable quanti-
the preservative, though a high degree of penetration
not often secured without the use of pressure.
process
is
304.
Creosoting.
— The apparatus employed
metallic cylinders having
made
cylinder,
typical
consists of
to close steam-tight.
upon which runs
be treated.
A
one
end doors which open
to the full size of the cross-section of the cylinder,
are
A
described in the next paragraph.
more heavy
or
to
97
depends upon the quantity
the quantity
If
1
porosity and permeability
its
is
treated.
large quantities of
If
cases
all
of applying the fluid
applied
sive plants are
PREPARATION.
ITS
and which
track extends through the
a truck or car carrying the material
Pumps and
other accessory apparatus are in
pipe connection with the cylinder.
The timber
to be treated
is
loaded on a truck and run into
the cylinder, after which the doors are securely closed.
under considerable pressure
and
this heats the
pores of the its
is
timber and supplies moisture to
wood and pressure
porosity.
to force
it in,
This accomplished, the steam
vacuum pump
is
employed
to
Steam
then admitted to the cylinder, fill
the
thus augmenting is
shut off and a
reduce the pressure within the
cylinder to as low a point as possible, with the result that the
moisture forced into the wood, having served
opening the pores,
is
now drawn
out.
The
its
purpose in
liquid creosote
is
then introduced into the cylinder and under an increase of pressure
the
timber expands and the liquid penetrates far
beyond the surface
of the material.
Pieces which are not more
than eight or ten inches across are penetrated to their center.
BENCH WORK
I98 After the pressure
is
withdrawn, the surplus liquid
the doors are opened, and the as described It
is
WOOD.
IN
wood
is
drawn
The
off,
process
subject to several modifications.
usually unnecessary to treat
is
is
removed.
wood which
designed
is
for the interior of buildings, the process being chiefly valuable for such materials as
come
in contact with the
ground or are
used about the water.
STRENGTH OF TIMBER. The Strength
305.
to yielding
any form.
Timber
of
measured by
is
its
resistance
under the influence of external force applied
Timbers may be so located with reference
in
to the
load they sustain as to be strained in tension, or in compres-
by bending and in each case the maxiwhich can be offered by a piece of wood will have a different value. The maximum resistance also depends sion, or in shear, or
mum
;
resistance
upon the direction which the load
is
of the grain relative to the direction in
applied.
In general, knotty and cross-grained
wood is not so strong as clear and straight-grained pieces of the same material. Large timbers usually contain more imperfections in grain than small ones
which might be cut from the
larger bulk, and, hence, large timbers are likely to be relatively
weaker than small ones.
In general, the heavier woods are
the stronger.
Strength in Tension
306.
which
is
In a piece of wood, this separate fibers
is
the
making up the
low pine and Washington
pounds
is
measured by the resistance
offered to a force drawing in the direction of length.
for
sum
of the resistances of
cross-section.
fir
will
all
the
Long-leaved, yel-
withstand
about
12,000
each square inch of cross-section, while oak, Cana-
dian white pine, and red
fir
withstand about 10,000 pounds,
and the more common woods, such
as white pine,
Norway
TIMBER AND pine, spruce,
PREPARATION.
ITS
1
99
hemlock, cypress, and chestnut, from 6000
to
These values are remarkably large when one
9000 pounds.
considers the lightness of the materials involved.
Strength in Compression
307.
is
the resistance offered to
a force which tends to reduce the dimension of a material in the direction in
which the force
is
Columns which
applied.
stand upon a foundation or base of any sort, and bear a load
upon the
top, are in compression.
In this case the individual
many hollow columns firmly bound together. under compression occurs when the fibers, by sepa-
fibers act as so
Failure
and
rating into small bodies
act as a solid mass.
sliding over each other, cease to
This action
is
obviously assisted by the
presence of the smallest knot or the slightest irregularity in grain.
When
tested in the form of short
columns
grain runs lengthwise, the
common woods
compression of from 5000
to
in
which the
withstand loads in
8000 pounds per square inch
of
cross-section.
308.
Strength in Shear.
—A
pin which holds a tenon in
its
mortise (Fig. 191) must resist shear
to
draw the tenon out
of the tenon
which
is
of the mortise.
its
of
wood
pression.
to shear
is
much
Assuming the
is
is
is,
under is
with the grain.
to yield at
two points
The
in single shear.
less
applied
said to be in double shear,
is
would need
length, while the tenon
is
shear upon the pin
upon the tenon
Again, in the case cited, the pin it
The
shear.
across the grain, while that
way
force
Similarly, that portion
immediately beyond the pin
the condition stated, in
since in giving
when a
in
resistance
than that to tension or com-
stress to fall
on a piece one square
inch in section, the resistance to shear
is
greatest in white
oak, for which the value across the grain
is
2000 pounds and
with the grain about 800 pounds.
ance to shear across the grain
and with the grain from 350
to
is
In other woods the
from 600
600 pounds.
to
resist-
1400 pounds,
BENCH WORK
200 309.
IN
WOOD.
Strength under Transverse Loads
shown by
is
ance to forces which tend to bend the piece. to the question of strength
of stiffness,
A
which
green stick
dry.
of the trunk.
is
under the conditions stated,
is
stiffer
stiff
that
one that
as
Wood from
than light pine.
usually stiffer than that from the
In
is
often quite as important as that of strength.
only about two-thirds as
is
Heavy pine
butt of a tree
stiffer
is
resist-
Closely allied
all
is
the
upper part
full-grown pine trees the heartwood
is
than the sapwood, but in young pines, and also in
young, second-growth hard woods, the sapwood
is
stiffer.
the sapwood of second-growth hickory that
is
prized for
is
carriage spokes
and
tool handles.
The
It
load which can be with-
stood by a timber subjected to a bending force varies directly as
its
width, as the square of
length of the span.
its
depth, and inversely as the
For example, a timber
5
inches deep
and 4 inches wide is twice as strong as one which is 5 inches deep and 2 inches wide while one which is 2 inches wide and 10 inches deep is four times as strong as one which is 2 inches ;
wide and
5
inches deep.
Again, a timber which rests on sup-
ports 16 feet apart will carry but half the load which
may be
sustained by a similar timber which rests on supports 8 feet apart.
A
consideration of numerical values
aided by mathematical preparation.
is
difficult unless
Students who are inter-
ested should seek to master the theory of beams as presented in texts dealing with the strength of materials.
OCT 24 1905
