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PREFACE
This text has been prepared by the Enlisted Men’s Depart-
ment of The Signal Corps School, to provide a progressive
course in the use and maintenance of such woodworking and
metal tools, as a soldier may be called upon to use in the
various units of the Signal Corps.
Acknowledgement is made for the use of certain sections
of Bell System Practices in lesson number eight, in the use,
care, and maintenance of manila rope and blocks.
0574737
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Contents
TABLE OF CONTENTS
Lesson Page
1 — Classification, Care and Maintenance of Tools .... 1
2 — Use of Knife and Pliers, Wire Splices 9
3 — Measuring and Gauging 20
4 — Metal Working
5 — Soldering ....
5A — Wiring of Radio Equipment, Cords and Plugs
6 — Woodworking 79
7 — Miscellaneous Tools 92
8 — Rope, Splices, Knots and Blocks 99
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ass
TM 11—453
+\Vl Ob’ <J4| X
/./•" l/A Vs
TECHNICAL MANUAL LIBRARY
j 1 0 ma I
SHOP WORK
■' />
/ / WAR \! V '
Washington 25, D. €., 20 March 1044.
iangbs 1
No. 1 |
TM 11-453, 11 March 1942, is changed as follows:
LESSON 1
CLASSIFICATION, CARE AND MAINTENANCE OF TOOLS
ale ******
6. Maintenance of screwdrivers. — The screwdriver is * * *
ily, driving screws. Do not use it as a chisel, nailpuller, can opener
for any job that may damage the tool. The screwdriver
* * * he commonly uses. Some errors of maintenance and
;e of this tool are illustrated in figures 3a, 3b, 3c, and 3d.
The broad flat * * * of uniform thickness.
u>
Figure 3d
To repoint a screwdriver blade, square the point of the tip
id bevel the edges and the flat surfaces of the blade. This
ay be done in the following manner:
Select a flat steel file. Clean as indicated in lesson 4, para-
aph 1, if the teeth of the file are clogged. Set up the work
i that the elbow will be level with the surface being filed.
Use a vise, if available, to secure the screwdriver in place,
aving both hands free for guiding the motion of the file.
To square the point of the tip, the screwdriver is secured in
perpendicular position, with the tip pointing upward (fig.
f)). File with a diagonal stroke, making the tip smooth
id straight and squared with the edge of the blade.
To bevel the edges of the blade the screwdriver is placed in J
horizontal position (fig. 5©). The upper edge of the blade
filed at a slight angle, using a diagonal stroke. When the
ge is filed to the required width, the other side of the edge
turned up, and is filed in the same manner.
To bevel the flat surfaces of the blade (fig. 5©) , follow the
me procedure as described in beveling the edges of the
ade. (Lesson 4, paragraph 1, contains additional filing
rections.)
577113° — 44 1
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FERRULE
SIZE
. BLADE
TL9035B
Figure 4 (Added.)
[A. G. 300.7 (14 Jan 44).) (C 1, 20 Mar 44.)
Figure 5 (Added.)
[A. G. 300.7 (14 Jan 44).] (C 1, 20 Mar 44.)
Some safety precautions * * * hands or face.
[A. G. 300.7 (14 Jan 44).] (Cl, 20 Mar 44.)
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7. "Wood bits (Added). — Wood bits are sharpened by filing,
le filing tools should include a small, half-round file, an auger bit
e with safe edges, and a small triangular or square file. All wood
ts have the same general features and are sharpened in the same
inner. The two parts which may need sharpening are the cutting
[A. G. 300.7 (14 Jan 44).] (C 1, 20 Mar 44.)
APPROX. 15°
RAKE ANGLE
TOP CUTTING
EDGE
TL 90361
Figure 7 (Added.)
[A. G. 300.7 (14 Jan 44).] (C 1, 20 Mar 44.)
ps or cutters (fig. 6) and the spurs. With the usual types of wood
ts, touch-up filing is worked through the throat (fig. 7), using either
ie half-round file (if the throat is rounded and small) or the auger
t file (if the throat is open). Spurs are always sharpened on the
iside, never on the outside (fig. 8). An auger bit file should be used
hen sharpening spurs, because its uncut edges minimize accidental
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cutting of the lip surface. If the bit is very dull, the top of the cutting
edge should be filed (fig. 8). It is important that the original bevel
be maintained and that the surface following the cutting edge be filed
; flat completely across its width. If only a small portion of the edge of
the lip is filed, the rake angle of the bevel is lessened and the chip-lift
SHARPEN AUGER BITS WITH
A BIT FILE. FOR A KEEN EDGE
ALSO WHET WITH A SLIPSTONE.
SHARPEN THE SPURS ON THE
INSIDE TO PRESERVE THE
DIAMETER.
SHARPEN THE CUTTINC EDGES
ON THE TOP TO MAINTAIN THE
CLEARANCE ON THE UNDER SIDE.
THE CUTTINC EDGES MUST BE
KEPT EVEN. TL90362
Figure 8 (Added.)
[A. G. 300.7 (14 Jan 44).] (C 1, 20 Mar 44.)
ing ability of the cutting edge is destroyed. The use of small stonei
on the filed surface will give the sharpened surface a polish which in
creases the cutting efficiency of the tool.
(A. G. 300.7 (14 Jan 44).] (C 1, 20 Mar 44.)
Review questions. —
****** sfc
9. Name the safety precautions to be observed when using
screwdriver.
[A. G. 300.7 (14 Jan 44).] (C 1, 20 Mar 44.)
LESSON 2
USE OF KNIFE AND PLIERS, WIRE SPLICES
* * *
7. Field wire splice.
*
*
* %
* * *
*
*
* *
b. Measure one pliers * *
*
in figure 1.
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11. The field wire “T” splice.
* * ♦ • * *
Vfter the splice * * * in figure 8.
[A. G. 300.7 (14 Jan 44).] (C 1, 20 Mar 44.)
* * * *
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Review questions. —
****** *
16. (Added.) How many complete turns are made in the buttons
of the Western Union splice?
IT. (Added.) How many turns are made in (he neck of the West-
ern Union splice?
fA. G. 300.7 (14 Jan 44).] (C 1, 20 Mar 44.)
LESSON 2
LABORATORY
Tools and materials. —
Knife, TL-29 *Wire, bare copper, W-74 (104-
Pliers, side-cutting mil bare hard-drawn cop-
Pliers, long-nose per, also known as wire
Pliers, diagonal 104)
*Wire W-110 *Seizing wire, 22-gauge bare
copper
Items marked * are not placed on the memorandum receipt.
[A. G. .-100.T (14 Jan 44).] (C 1, 20 Mar 44.)
Procedure. —
****** *
Operation 3 . — Using 104 bare copper wire and W-110, make a
combination seizing wire splice.
Ins. check
I
Operation — Using wire furnished, make a tap splice.
Ins. check
Operation 5 . — Using wire furnished, make a Western Union
splice. Submit all splices to instructor for approval.
Ins. check
****** *
[A. G. 200.7 (H Jan 44).] (C 1, 20 Mar 44.)
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LESSON 3
MEASURING AND GAUGING
1. Steel scale.
* *
WIRE
GAUGE BY SLOT,
NOT HOLE
TL 90368
Figure 1
I A. G. 300.7 (14 Jail 44).] (C 1. 20 Mar 44.)
2. Wire gauges. — The wire gauge * * *
the copper wire.
LINE NEAREST
CENTER INDICATES
GAUGE
CI6 GAUGE)
CENTER OF SCREW
MIDDLE OF SHANK
LINE NEAREST
CENTER INDICATES
GAUGE
' — (6 GAUGE)
USE NEW
STANDARD GAUGE
TL 90370
677113
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Figure 1.1 (Added.)
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SHOP WORK
The circular wire * * * the correct gauge (fig. 1.1).
****** *
[A. G. 300.7 (14 Jan 44).] (C 1, 20 Mar 44.)
LESSON 4
METAL WORKING
* * * *
6. Taps and dies.
* * * *
* * *
* * *
LESSON 4
LABORATORY
****** *
Procedure. —
Operation 1 . — I sing the V^-inch x 1-inch brass stock, square the
ends with the files. Drill and tap a hole for a 12-24 thread..
Ins. check
Figure 8 (page 38) is rescinded.
Operation 2 . — Using the brass rod furnished, and size 14 — 20
die, cut a V^-inch thread on one end only.
Ins. check
Operation 3 . — Using the length of iron stock furnished, cut
14 -inch from one end and square the ends of the remaining
stock.
Ins. check
Operation 4 - — Cut a piece of sheet brass 1 inch square and
square all sides.
Ins. check
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Operation 5 . — Cut a piece of iron plate and square it. Form
the bracket shown in figure 9.
Ins. check
Operation 6 .. — Cut a piece of bakelite 1 inch square and square
all sides.
Ins. check
[A. G. *00.7 (14 Jan 44).] (C 1. 20 Mar 44.)
LESSON 5 (page 58)
LABORATORY
(Wire Students Only)
Tools and materials for operations 1, 2, 3, 4, and 5. —
* ******
*1 |>cs. Wire, copper, 104
* * * * * * *
[A. G. 300.7 (14 Jan 44).] (C 1, 20 Mar 44.)
Procedure. —
* ******
Operation 3 . — Clean and tin one end of each of the four pieces of
104 copper wire. The tinned portion * * * will be secured.
Ins. check
* ******
[A. G. 300.7 (14 Jan 44).] (C 1. 20 Mar 44.)
Tools and materials for operations 6 to 16 inclusive. —
* ******
*1 pc. 20-pr. switchboard cable
*1 ea. Brass rods, (4 inch x 12 inch
* ******
Items marked * are not placed on the memorandum receipt.
Inspect models on display board and table before doing any
of the operations below.
* ******
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Operation 0 . — Place the pairs * * * wires in place. If two
brass rods are used, lay the other rod * * * the terminal
block.
Ins. check
Operation 10. — Separate the first pair of wires (blue with white
mate). Lay the white wire across the edge of the mounting strip
so that it will be out of the way. Bend the coded (blue) wire into
the notch of the top terminal of the second row. (The terminals are
counted from the front to the back of the terminal block. The pairs
are counted from the top to the bottom of a vertical strip.)
The next step is to remove the insulation from the wire. Using a
pair of long-nosed pliers, and starting at a point marked by
the notch, crush the insulation about 1 inch toward the end
of the wire. Remove crushed insulation. Wind the loose
ends of the insulation tightly around the wire with the fingers,
and slip back about to facilitate the removal of
enamel or tarnish. Enamel or tarnish may be removed by
use of insulation strippers or the long-nose pliers. After the
wire has been cleaned thoroughly, pull the insulation back
and wind tightly so that the insulation comes under the ter-
minal but does not enter the notch. Wind the bare wire
around the terminal, making one complete turn, beginning
and ending in the notch. Excess wire is removed by severing
it in the notch. When working with wire of a larger gauge
(18 gauge or larger), or on terminals that are not very rigid,
severing may be accomplished by pulling the wire taut and
bending it from side to side.
Solder the connection and inspect for the faults listed below :
* * * * * * *
c. Rosin joints. (Not enough heat.)
<1 . Solder not adhering to wire. (Must Ik* unsoldered and wire
scraped.)
After the connection has been inspected, and all faults corrected,
if the student is in doubt as to whether the connection has been sol-
dered properly, have the instructor check it before soldering others.
Continue with the coded wires until all 20 have been soldered.
Ins. check
****** *
Operation 12. — Lash another piece * * * block mounted hori-
zontally. Wires should be fanned through the bottom of the
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horizontal strip. Place and solder * * * instructor for ap-
proval.
Ins. check
Operation 13. — Place five pairs of cross-connecting wires
from the vertical protector strip to the top punchings of the
horizontally mounted terminal block. This wire is not dressed
back against the fanning strip. Each pair of cross-connecting wires
should have approximately 3 inches of slack. These wires are con-
nected and soldered on the horizontal block as in operation 10.
In connecting to the vertical protector strip, the insulation
should come up to, but not enter, the notch. The method
outlined in operation 10 for removing insulation and attach-
ing wires to punching will be followed. Solder is applied on
the face of the punchings. Check the connections for faults and
submit to the instructor for approval.
Ins. check
* ******
Operation 16. — Rescinded.
[A. G. 300.7 (14 Jail 44).] (C 1. 20 Mar 44.)
LESSON 5A
WIRING OF RADIO EQUIPMENT, CORDS AND PLUGS
(For Radio Students Only)
* * * * * * *
3. Cable wiring. — Cable wiring is * * * work being done.
Figure 9
TL 90373
A figure eight * * * then cut off. The wires are laced to-
gether with a lock stitch. Do not use a half -hitch. The half-
hitch will not hold the form together if the lacing cord is
broken. At the points marked A and B in figure 9, the twine
must be on the under side. If either A or B is on top when
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the stitch is made, it is called a half-hitch. When the lacing is
completed, the twine is anchored by placing two or three stitches
behind the last stitch of the form. See figure 9.
Figure 10. Rescinded.
****** =*
[A. U. 300.7 (14 Jan 44). J (<’ 1. 20 Mar 44.)
Review questions (Added). —
1. Should bus wire be insulated if it is likely to come in contact with
other wires in a radio set?
2. How long is the bent -over part of the butt joint ?
3. What is done to a stranded wire before a satisfactory loop can
be made ?
I 4. When is cable wiring used ?
5. Will cordage shielding in any case be found on the outside of the
/ rubber jacket ?
6. What is the proper tool to use in removing the rubber jacket
from a cord ?
7. What trouble may develop if all the strands of a conductor are
not soldered into place?
8. Should the cutting blade of a knife be used to clean wire?
[A. G. 300.7 (14 Jan 44).] (C 1. 20 Mar 44.)
LESSON 5A
LABORATORY
(For Radio Students Only)
Tools and materials for operations 1 to 6 inclusive. —
* 1 ea. Blow torch * 4 pcs. Wire, copper, 104
****** %
Items marked * are not placed on memorandum receipt,
I A. G. 300.7 (14 Jan 44).] (C 1. 20 Mar 44.)
Procedure. —
****** afc
Operation S . — Clean and tin one end of each of the four pieces of
104 copper wire. The tinned portion * * * will be secured.
Ins. check
****** *
[A. G. BOO. 7 (14 Jan 44 ).] (C 1, 20 Mar 44.)
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Tools and materials for operations 7 to 14 inclusive. —
1 each Soldering iron TL-117
1 each Pliers, 6-inch side-
cutting (TL-13)
1 each Pliers, long-nose
(TL-126)
1 each Pliers, diagonal
(TL-103)
1 each Knife TL-29
1 each Small screwdriver
1 each Chassis
1 each Plug PL-50
1 each Plug PL-61
*1 ea. File, 10-inch, with han-
dle
1 ea. File, card
*6 pcs. Wire No. 14, enameled
*1 bundle Wire, for chassis wiring
*3 Terminals, mounted on block
*1 pc. Cordage CO-130
*1 pc. Cordage CO-138
Items marked * are not placed on the memorandum receipt.
Inspect models on * * * the operations below.
*
*
*
Operation 10 . — One satisfactory loop must be completed to fit the
machine screw furnished.
Ins. check
* ******
Operation 13 . — Rescinded.
*******
[A. G. 300.7 (14 Jan 44).] (C 1, 20 Mar 44.)
LESSON 6
WOODWORKING
* * * * *
3. Laying out the work.
*****
Marking gauge. — This tool consists * * *
Do not use the tool across the grain.
* * * * *
* *
* *
along the grain.
* *
Transferring the dimensions . — A pencil with * * * cannot be
used. A pencil or knife used in conjunction with a square or
straight edge should be used to mark across the grain. The
knife or pencil should have the upper end tilted away from the square
or rule.
(Figure 1)
[A. G. 300.7 (14 Jan 44).] (C 1, 20 Mar 44.)
7. Mallets. — The wood mallet * * * wooden pins, etc. Mal-
lets are sometimes made of lead, brass, or plastic.
[A. G. 300.7 (14 Jan 44).] (C 1. 20 Mar 44.)
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12. Claw hammer. — The claw hammer * * * for removing
nails.
If it is necessary to hammer a nail with the use of only om
hand, proceed as follows: insert the nail between thi
hammer claws (fig. 3.1(T)), with the head of the nail agains
the base of the hammer head, so that the nail remains rigidl]
in position. Drive the nail deep enough with the first blow s<
that it will remain in the wood until struck again with th
face of the hammer.
Another method for hammering a nail with one hand i
shown in figure 3.1(f). Grasp the hammer head so that th
side of it will be used for driving. Hold the nail head agains
the side of the hammer, and drive the nail deep enough witl
the first blow so that it will remain in place to be strucl
again in the usual manner.
[A. G. 300.7 (14 Jan 44).] (C 1, 20 Mar 44.)
Figure 3.1 (Added.)
[A. G. 300.7 (14 Jan 44).] (C 1, 20 Mar 44.)
16. Fastening devices.
****** sic
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Naite . — The wire nail * * * by the figure.
Common Wire Nails (Added.)
Size
Length
(inches)
Gauge
number
Diameter
(inches)
approximate
i
Approxi-
mate
number to
1 pound
2D
1
15
/ 64
876
3D
i m
14
568
4D
; ite
12H
H 2
316
! 5D
m
12 h
H 2
271
6D
2
11 \i
7 A 4
181
7D
2H
ii y 2
7 Aa *
161
8D
2H
10H
H
106
9D
234
! ion
A
96
10D
3
9
%2
69
12D
i 3H
9
5 A2
63
16D
8
b '^2
49
20D
4
6
Me
31
[A. G. 300.7 (14 Jan 44).] (0 1, 20 Mar 44.)
60 90 100 120 160 200
TL 90375
Figure 5 (Added.)
[A. G. 300.7 (14. Ian 44). J (0 1. 20 Mar 44.)
* ******
LESSON 7
LABORATORY
rools and materials. —
* ******
*4 pcs. 104 copper wire.
a* ******
[terns marked * are not placed on the memorandum receipt.
sfc * * * * * *
[A. G. 300.7 ( 14 Jan 44).] (C 1, 20 Mar 44.)
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LESSON 8
ROPES, SPLICES, KNOTS, AND BLOCKS
1. General information on rope. — .
*******
e. Selecting the size of rope for the work to be performed . — The
approximate weight * * * fibres to break. Table 3, page 130,
shows the proper size ropes for the various size blocks. (See rigging.)
****** *
[A. G. 300.7 (14 Jan 44).] (C 1, 20 Mar 44.)
2. The more common rope splices. —
****** *
b. Crown splice. — See figure 2 (b).
****** *
(6) Continue the weaving in the following manner (fig*
2(b)F) :
(a) Place one of the loose strands over the nearest main
strand; tuck it under the next main strand, pulling it at a 45°
angle to the rope.
(b) Turn the rope counterclockwise until the next loose!
strand is forward. Place this strand over the nearest main
strand and tuck it under the next main strand.
(c) Again turn the rope counterclockwise until the next
loose strand is in the forward position. Follow the same pro-
cedure as in (b) above.
*******
c. Eye splice . — The eye splice * * * in figure 3-A-D.
(1) Untwist the strands * * * the eye required. Be certain
that the middle strand 2 is placed under the rope (fig. 3— A).
(2) (Superseded.) Tuck strand 1 under one of the main strands
of the rope at the point where weaving is to start (fig. 3 -B).
(3) (Superseded.) Place strand 2 behind the rope (fig. &-A).
(4) (Superseded.) Tuck strand 3 under the next main strand,
directly below strand 1 (fig. 3-Z?).
(5) (Added.) Turn the rope over, and tuck strand 2 under the
third main strand of the rope. This brings strand 2 through the
main rope between strands 1 and 3 (fig. 3 -B).
(6) (Added.) When all the ends have been tucked through for the
first time, pull them down tight as in 3 -C. Proceed to interweave the
strands as follows :
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(a) Pull strand 2 toward the top of the eye. Place strand 1 over
he nearest main strand and tuck strand 1 under the next main strand,
.’his should place strand 1 between strands 2 and 3.
( b ) Place strand 2 over the nearest main strand and tuck it under
he next main strand.
(c) Check the weaving to make certain that one main strand of
he rope always separates the two other strands.
(d) Continue interweaving as in b( 6) above until the total length
f the interwoven strands, for i^-inch rope, extends a distance of 4
aches. Add one tuck for each next larger standard size rope.
( e ) Roll the splice between two flat surfaces under pressure as be-
ween foot and floor, and trim off surplus ends flush with the outside
trands. The completed splice is shown in figure 3 -D.
d. /Short straight splice. — Short straight splice * * * of the
ope. See figure 3-E-G.
(1) Untwist the strands * * * 10 to 16 inches. Butt the
inds of the rope tightly together as in figure 3— E laying the
hands * * * locking the strand.
[A. G. 300.7 (14 Jan 44).] (C 1, 20 Mar 44.)
TL 90376
(2) (Superseded.) Hold the even-numbered strands and the rope
ightly in the left hand. With the right hand, aided by the thumb
nd forefinger of the left hand, weave the odd-numbered strands in
he following manner :
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(a) Place one of the loose odd-numbered strands over the nearest
main strand and tuck it under the next main strand, pulling it up to
a 45° angle to the rope. Turn the rope counterclockwise until the
next loose odd-numbered strand is forward. This strand, as well as
the next, and last odd-numbered strand, are handled in the same man-
ner as described above.
(b) The operation just explained is related with the even-num-
bered strands, producing an arrangement similar to that shown in
figure 3-F. Continue the interweaving on alternate sides until it?
total length extends a distance of 4 inches for 14-inch rope. Add
another tuck for each next larger standard size rope.
(3) (Superseded.) Roll the splice between two flat surfaces under
pressure (between the foot and floor), and trim off the surplus ends
flush with the outside strands. The completed splice is shown in
figure 3-G.
(4) Rescinded.
(5) Rescinded.
* * * * * * *
[A. G. 300.7 (14 Jan 44).] (C I. 20 Mar 44.)
4. Blocks.
* * * * * * *
c. Manila rope snatch blocks. — Snatch blocks are * * * they
will carry. A snatch block may be defined as a single sheave
block, with a hinged swivel hook. Snatch blocks are illustrated
in figure 21 (b) .
* * * * * * *
fA. <i. m>0.7 (14 Jan 44 >.] (C 1. 20 Mar 44.)
LESSON 8
LABORATORY
Tools and materials. —
1 ea. Knife TL— 29
* * * * * * *
Blocks for reeving will be found in the class room.
* * * * * * *
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I A. a. :u)0.7 (14 Jan 44).] (Cl, 20 Mar 44.)
By order of the Secretary of War :
Official :
J. A. CLIO,
Major General.
The Adjutant General.
20
by CjOOglc
G. C. MARSHALL,
Chief of Staff.
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“• *• 7^!5TirCT’ P** : 0RN A
TM 11-453
TECHNICAL MANUAL 1 WAR DEPARTMENT,
No. 11-453 } Washington, March 11, 1942
SHOP WORK
LESSON 1
CLASSIFICATION, CARE AND MAINTENANCE OF TOOLS
1. Classification. — Tools are divided into two general
classes: machine tools and hand tools. Machine tools are
visually driven by electric motors, and are used where the
volume of work performed is great enough or the labor
saved is sufficient to warrant their cost. Examples: lathe,
circular and jig saws, drill presses and milling machines.
Hand tools are those held in the hand, or those in which title
operator furnishes the motive power. Examples: hand saws,
knives, pliers, planes, miter boxes, etc.
Tools are further subdivided according to their use as
layout, cutting, boring, driving, holding and sharpening.
2. Cara of tools. — The work bench, classed as a holding
tool, very seldom gets the care it should have. The top
should be cleaned at the completion of each job, or daily,
before leaving the shop. Vises attached to the work bench
should be wiped off and inspected for rust at the same time.
Do not allow trash to accumulate in the drawers. Heavy or
rough work, assemblies which have sharp edges and other
types of work that might gouge into the top of the bench
should be handled from the floor or on special racks.
A salt, present in perspiration, causes rust to form on
metal tools. Wip£ hll metal tools off with an oily rag, after
a job has been completed; also before returning them to the
store room.
The correct storage of tools plays an important part in
their care. Cutting and boring tools should be placed in racks
or drawers which will protect their cutting edges, and while
in use on the work bench, Should be placed so that their
cutting edges will not come in contact with other tools.
The rivets in the hinges of pliers and similar tools should
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Lesson 1
Shop Work
be oiled occasionally to keep them working freely. Layout
tools must not be dropped, used as a pry, to drive screws
or as a scraper. This abuse will render them inaccurate.
Inspect the handles of all driving tools frequently, see that
they are tight and free from checks and splinters. When
tools are to be stored for some length of time, a lubricant
such as vaseline or heavy gunoil should be spread over all
metal parts. Thin oil breaks down and allows atmospheric
moisture to corrode the metal. No mechanic, however ex-
pert, can do first class work with an unserviceable tool.
3. Maintenance of tools, shaping and sharpening. — Cutting
and driving tools such as chisels, knives, twist drills, wood
bits and screwdrivers must be correctly shaped and sharp-
ened in order to perform first class work. Tools are shaped
and large nicks removed from cutting edges by the use of
carborundum wheels and stones, and grindstones. Oilstones
are used for honing, which brings the cutting edge to the
correct degree of keenness.
The grindstone is used for shaping and sharpening low
temper tools such as adzes, hatchets, axes, cable knives,
etc. Water is used on the grindstone to reduce the heat
caused by friction, thus preserving the temper of the tool.
The surface speed of wheels used to shape and sharpen high
temper tools such as plane cutters, wood chisels, twist drills,
metal working bits, etc., is too great to permit the use of a
lubricant on the wheel itself. The temper of the tool is pre-
served during the grinding process by dipping it frequently
into a can of water to keep it cool. Grindstones and carbor-
undum wheels should revolve toward the user. This removes
the metal from the cutting edge of the bevel and not from
the heel.
A light oil is used on the surface of all flat stones, whether
carborundum or oilstones, to prevent the small particles of
metal removed from the tool from sinking into the stone.
When the oil becomes dirty, wipe it off with a rag and place
fresh oil on the stone. Do not grind or hone in one spot,
work the tool over the entire surface of the stone. This keeps
the surface level.
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Classification, Care and Maintenance of Tools
Lesson 1
The following is a good test for a serviceable cutting edge.
Place the cutting edge on the thumbnail, exert a light pres-
sure, and draw the edge along the nail. If it “clings” to the
nail the tool is correctly sharpened.
4. Sharpening the knife. — The knife is a double bevel tool,
usually of low temper steel. Do not grind the knife on the
carborundum wheel. If the nicks are too large to remove
with a flat stone use the grindstone. The knife is sharpened
by stroking first on one side of the blade and then on the
other, moving the tool so that the cutting edge always meets
the stone first.
Figure 1
The correct stroking motion is illustrated in figure 1. The
angle between the knife blade and the stone is about twenty
degrees. After the nicks have been removed, hone to the
correct cutting edge on the oilstone.
5. Chisels and plane cutlers. — Plane cutters, chisels, gouges
and similar single bevel cutting tools should first be ground
square on the carborundum wheel. Check with a try square,
testing from one edge of the tool only. With proper care, the
single bevel type of tool need not be ground often. A few
minutes spent in honing the tool on the oil stone will keep
the cutting edge serviceable. A good general rule to follow
is: If the honed part of the bevel exceeds one half of its total
length the tool should be reground.
The angle of the bevel varies with the type of work to
be performed. A good angle for general work is 25 degrees,
soft wood or material is worked with a 20 degree bevel while
hard wood requires a 30 degree bevel. Small nicks are re-
moved by flat grinding on a carborundum stone. The bevel of
the tool must be exactly parallel with the surface of the
stone. Use one hand to guide the tool, the other to apply a
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Lesson 1
• Shop Work
moderate amount of pressure and move the tool over the
entire surface of the stone with a rotary motion as illus-
' trated in figure 2.
TL-J258
Figure 2
Use as small a circle as possible, as this gives better con-
trol over the tool. A rocking motion should be avoided, as
this soon destroys the hollow grind obtained from the car-
borundum wheel and makes it practically impossible to
sharpen the tool on a flat stone without regrinding. As the
cutting edge of the bevel becomes thin, it will be noted that
a burr or wire edge is formed on the back of the tool. This
is removed by placing the back of the tool absolutely flat
on the stone and using the rotary motion illustrated in
figure 2. Plane cutters usually have a small portion of each
end ground off to prevent them from biting into the wood
being smoothed. When all nicks have been removed from the
tool, hone to the correct cutting edge on the oilstone, using
the procedure given above.
6. Maintenance of screwdrivers. — The screwdriver is proba-
bly more abused than any other tool. It is made for one
purpose only, driving screws. Do not use it as a chisel,
nailpuller, canopener or other jobs for which it is unfitted.
The screwdriver is made of a very tough grade of steel due
to the torque applied to it when driving screws. Every
mechanic should have several screwdrivers each ground and
correctly shaped to fit some screw he commonly uses. Some
errors of maintenance and use of this tool are illustrated
in figure 3.
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Classification, Care and Maintenance of Tools
Lesson 1
The broad flat surfaces are ground slightly concave on
the carborundum wheel or shaped with a file. The two sur-
faces must have an equal taper in order to keep the tip on
the center line of the shank. The end of the blade must have
the sides parallel for the depth of the screw slot. The tip
should be square and of uniform thickness.
Figure 3a
/ / / '*'/ ~y Center line ol shank
j l L ' out of line with center
line of screw.
Tip slips out of slot,
wood and slot
marred.
TL -ZIM'Z
Figure 3b
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Lesson 1
Shop Work
! tip loo thick, does
not seat property
in slot Top of
screw heed may
be sheered off
Screws with damaged slots are difficult to
remove. Difficult jobs, take extra time.
Extra time increases maintenance costs TL m 2133*3
Figure 3c
Broken tip concentrates the
stresses in the remaining
portion of the blade. This
may bring about breakage
of the other side of the tip
T L*2t63~4
Figure 3d
Some safety precautions to be observed when using the
screwdriver are, always drive a screw with the center of
the screw and screwdriver in line; do not carry a screw-
driver in a pocket, where injury may result through ex-
posure of the point of the blade; never use a screwdriver
with a bent blade and always work in such a manner that
if the screwdriver slips, it will not cause injury to the hands
or face.
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Classification, Care and Maintenance of Tools
Lesson 1
The maintenance of twist drills and wood bits is an exact-
ing job. The instructor will give group instruction in the
correct procedure when necessary.
Review questions. —
The answers to all review questions will be found in the
text. Do not consult the instructor regarding these questions
unless you are unable to find an answer for them.
1. Name the two general classes of tools.
2. Name two things to be remembered about the care of
hand tools.
3. Name two stones that are used to remove nicks from
tools.
4. What is the oilstone used for?
5. What test is used to determine if a tool has a service-
able cutting edge?
6. Are knives and plane blades sharpened the same way?
7. How is the wire edge removed from plane blades and
chisels?
8. Should a screwdriver with a bent blade ever be used
to drive screws?
9. Name one safety precaution to be observed when using
a screwdriver.
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Lesson 1
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RESTRICTED
LESSON 1
LABORATORY
Tools and materials. —
Plane cutter
•Oilcan
•Rags
placed on the memorandum receipt.
Procedure. —
Oilstone
Carborundum stone
Knife, TL-29
Wood chisel
Items marked * are not
Operation 1 . — Using the oil and carborundum stones,
sharpen the knife, TL-29. These stones break easily, and
must be handled carefully.
Ins. check
Operation 2 . — Sharpen the plane cutter. Follow instruc-
tions given in the lesson sheet.
Ins. check
Operation 3 . — Sharpen the wood chisel. If the student is
unable to determine if the plane cutter or wood chisel re-
quires grinding, consult the instructor. Submit sharpened
tools to instructor for approval.
Ins. check
Operation 4 - — Examine one of the sets of screwdrivers dis-
played on bulletin board.
Ins. check
List the faults found below:
1 .
2 .
3.
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Use of Knife and Pliers, Wire Splices
Lesson 2
LESSON 2
USE OF KNIFE AND PLIERS, WIRE SPLICES
1. Electricians knife, TL-29. — The three major parts of this
knife are : handle, screwdriver and cutting blade. The screw-
driver blade is provided with a lock, which protects the user
when this blade is opened. Never have both blades open at
the same time. The cutting blade is used to whittle soft
materials and to remove insulation from wires. Do not use
this blade to scrape wires. The screwdriver blade is used to
drive small screws. If necessary, it may also be used to clean
wires. When using the cutting blade, do not cut toward the
body.
2. Pliers, general. — Pliers are classified according to their
length and by the shape of their jaws. Examples: 6-inch
side-cutting, 4-inch diagonals. Pliers are made in various
lengths, with a wide variety of jaw shapes, each intended
for some specific use. The important points to remember
when using pliers are: keep them clean and free from rust,
use a size and jaw shape that will do the work correctly,
never use the pliers as a wrench or hammer. The three types
of pliers used most commonly by signal specialists are: side-
cutting, diagonal and long-nose.
3. Side-cutting pliers, TL-13 (Commercial lineman’s 6-inch
side-cutting ) . — This type of pliers is equipped with blunt
jaws, which have a scored gripping surface, side wire cut-
ters, parallel heel surfaces, and strong handles. The gripping
surfaces do not close completely, as this would interfere
with the cutters. These pliers are used for insulation crush-
ing (use the heel) , gripping, wire splicing, wire cutting and
insulation stripping. When removing insulation, do not per-
mit the jaws to touch bare wire. Never cut solid wire
completely apart with pliers, as this may damage the cut-
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Lesson 2
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ters. Nick it, then use the gripping part of the jaws to bend
the wire back and forth until it breaks.
4. Long-nose pliers. TL-126 (Commercial 6- or 6V2-inch). —
Long-nose pliers have long, slender jaws, flat on the inside.
They are usually scored on the inside of the jaw, near the
end of the pliers. Some long-nose pliers are made with
cutters, but the greater majority do not have them. Long-
nose pliers are used for gripping, reaching places not readily
accessible to the hand, holding wires, bending loops, attach-
ing wires to terminals and punchings, skinning and splicing
small wires.
Wire insulation is crushed with the long-nose pliers, pro-
viding they are not equipped with cutting jaws, by sliding
the wire down the base of the jaws and squeezing down on
the handles. The insulation can now be removed easily from
the wire, and if necessary, the gripping surfaces of the jaws
may be used to clean the wire.
Do not use this type of pliers to hold large objects, tighten
nuts or bend the larger gauges of wire and sheet metal.
Such practice soon springs the jaws, rendering the pliers
unserviceable.
5. Diagonal pliers, TL-103, (Commercial 5-inch). — This type
of pliers is equipped with cutting jaws, set at an angle of
about fifteen degrees from the handles, making them more
efficient in close places than side cutting pliers. The principal
use of these pliers is cutting small gauge wires. These pliers
should not be used to cut wires larger than 16 gauge steel or
14 gauge copper.
6. Wire splices, general. — The installation of wire systems,
both field and permanent, requires the use of a variety of
wire splices. The splice used will depend primarily on the
types of wires to be connected. Regardless of the type of
splice used, the following principals must be observed:
Thoroughly clean bare portion wires before joining.
A wire is not clean unless all tarnish or oxide is removed.
Do not nick the conductor, if the wire is stranded care
must be exercised in removing insulation so that all strands
remain intact.
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Use of Knife and Pliers, Wire Splices
Lesson 2
Apply tape to splices on insulated wire, to restore the
insulation and render the splice waterproof (see paragraph
12 ).
When splicing twisted pair, (field wire splice), the joints
should be staggered at least 6 inches. This helps to prevent
short circuits, and reduces the bulk of the splice.
»
7. Reid wire splice. — The standard field wire splice, made
in wires type W-110 and W-110-B, using copper seizing wire,
is made as follows (also on older obsolete types of wire) :
a. Cut the ends of both wires off square.
b. Measure one plier’s length on one conductor (about
6 inches) and cut this length off, as illustrated in figure 1.
* Figure 1
c. Crush and remove insulation from long and short con
ductor as indicated in figure 2.
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Use of Knife and Pliers, Wire Splices
Lesson 2
d. Tie the square knot, using one long and one short
conductor, as indicated in figure 3.
Figure 3
Note . — The square knot should be tied in both conductors
without delay, to restore service to circuit before starting
to perform the following operations:
e. Seize the splice as shown in figure 4.
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Lesson 2
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.? turns on rupber
TL-1725
Figure 4c
Figure 4d
8. Combination seizing wire splice. — This splice is used to
splice a stranded conductor insulated wire to a solid conduc-
tor bare wire. Strip about one inch of insulation from the
stranded wire and clean both wires so that they are bright
and free of corrosion. Lay this end of the stranded wire
along the solid wire. Begin the seizing by taking four turns
with the seizing wire around the solid wire only, back of the
stranded wire. Continue wrapping, including several turns
over the insulation of the stranded wire, then over the bare
end of the stranded wire, and finish with four turns over
TL-696 t
Figure 5
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Use of Knife and Pliers, Wire Splices
Lesson 2
the solid wire only. Wrap the seizing wire tightly and draw
the turns closely together. This splice will pull away very
easily, therefore the stranded wire should be tied in to a
fixed object near the splice to prevent any strain being
imparted to the splice proper. See figure 5.
9. Tap splice. — This splice is used to tap a wire into a
permanently installed line wire without cutting it. It may
be made with either solid or stranded conductors, or a com-
bination of both. To make the splice, remove 1 inch of
insulation from the permanently installed wire and about
3 inches from the other wire. Lay the cleaned end of the
tapping wire over the line wire. Make one wrap around the
permanent wire with the tapping wire. Bring the end of the
tapping wire across the standing part of the tapping wire,
underneath the permanent wire, and with the remainder of
the cleaned end of the tapping wire, place five close turns
around the permanent wire. See figure 6.
10. Western Union splice. — The Western Union splice is used
when splicing two solid wires together. Strip the insulation
from the ends of both wires for about 8 inches and clean
them so that they are bright and free of corrosion. Make
the splice as illustrated in figure 7. The twisted portion, com-
posed of three complete turns is called the “neck.” The five
close turns at each end are known as the “buttons.” The
wires in the neck should be in dose contact with each other.
Cut the ends of the buttons off as dosely as possible, being
careful not to leave' a sharp point that will puncture the
tape wrapping.
11. The field wire “T” splice. — This splice is used to tap a
field wire drcuit without causing interruption to service.
465422 0 - 42 - 2 .1 r
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Lesson 2
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Figure 7
After the splice is completed, the end of the circuit if no
longer required, may be cut free. In any case, this splice
is seized and taped in the same manner as other field wire
splices. The amount of insulation removed from the main
wire is about 1V> inches. Make the splice as illustrated in
figure 8.
1 2" or more
TL-1&2QA
12. Taping the splice. — For best results, the splice should
be held taut when applying the tape. Each splice is protected
with two reversed layers of rubber tape and friction tape.
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Use of Knife and Pliers, Wire Splices
Lesson 2
Applying the rubber tape: Use a piece about 4 inches long.
Start in the center of the splice and wrap toward the right
until the V 2 inch of rubber insulation has been covered.
Reverse the wrap toward the left until % inch of rubber
insulation is covered then reverse and end wrap in center.
The tape must be stretched, the ends of the wrapping should
be pressed down tightly to keep the splice waterproof and
each turn of the tape should cover half of the one previously
applied. See figure 9.
Applying the friction tape: Apply two reversed layers of
friction tape over the rubber tape in the same manner except
this time extend the wrap to inclose about 1 inch of braid
to hold the braid in place. The overall length of the finished
TL -1722
Figure 9b
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Lesson 2
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splice should not exceed 4 inches. Roll the splice several
times in the hands to seal the edges of the tape.
Review questions. —
1. Name the three major parts of the electricians knife.
2. How are pliers classified?
3. What is the principal use of the diagonal pliers? Name
the largest size steel wire that may be cut with these pliers,
the largest size copper.
4. Name two uses of the side-cutting pliers.
5. How much stagger is placed in a field wire splice?
6. What Knot is used to make a field wire splice?
7. How much space is left between the knot and the
rubber insulation in a field wire splice? How much rubber
insulation is exposed?
8. When would a combination seizing wire splice be used?
9. What is used to insulate a field wire splice?
10. Name one important point to be observed when using
pliers.
11. Why is it advisable to stagger the splices made in
twisted pair wire?
12. What is the tap splice used for?
13. How is solid wire parted when using side-cutting pliers
to cut it?
14. What is the amount of stagger used when making a
“T” splice?
15. Name three uses of the long-nose pliers.
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Use of Knife and Pliers, Wire Splices
Lesson 2
LESSON 2
LABORATORY
Tools and materials. —
Knife, TL-29
Pliers, side-cutting
Pliers, long-nose
Pliers, diagonal
•Wire W-110
•Wire, bare copper No. 10
•Wire W-38 or W-50
•Seizing wire, 22-gauge bare
copper
Items marked • are not placed on the memorandum receipt.
Procedure. —
Operation 1 . — Using wire W-110, make a field wire splice.
Ins. check
Operation 2 . — Using wire W-110 make a “T” or field wire
tap splice.
Ins. check
Operation S . — Using number 10 bare copper wire and
W-110, make a combination seizing wire splice.
Ins. check
Operation If. — Using wire W-38 or W-50, make a tap
splice.
Ins. check
Operation 5 . — Using wire W-38 or W-50 make a Western
Union splice. Submit all splices to instructor for approval,
Ins. check
Operation 6 . — Following the instructions in the informa-
tion sheet, tape the splices made under operations 1 and 3.
Ins. check
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Lesson 3
Shop Work
LESSON 3
MEASURING AND GAUGING
1. Steel scale. — The steel scale is a metal ruler with, one
or more of its edges accurately marked with some fractional
part of the inch or meter. The most commonly used scale is
the number 4 graduation . The edges of this scale are laid
out as follows: 1st edge, 8th of an inch; 2d edge, 16ths of
an inch; 3d edge, 32ds of an inch; 4th edge, 64ths of an inch.
The steel scale is used for all linear measurements where a
high order of accuracy is required, also as a straight edge
to determine whether a surface is absolutely flat.
Figure 1
2. Wire gauges. — The wire gauge is a tool used for measur-
ing the diameter of wire. The most common forms of this
gauge are, the circular wire gauge and the combination
wire and screw gauge. Wire diameters are given in two ways,
by a gauge number and in mils. One mil equals l/1000th of
an inch. Examination of the gauges will reveal that the
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Measuring and Gauging
Lesson 3
larger the gauge number, the smaller the diameter of the
wire. There are several different standards for wire gauges
in the United States (see table I) . The wire standards most
commonly used are the American or Brown and Sharpe for
copper and Birmingham or Stubbs for iron wire. It will be
noted that for any given gauge size the iron wire is few mils
larger in diameter than the copper wire.
The circular wire gauge is used to measure wire as shown
in figure 1.
Do not force the wire into a slot. Find the slot that refuses
to pass the wire without forcing, then try next larger until
one is found that passes the wire. This is the correct size.
The combination wire and screw gauge is used in practically
the same way, except that the wires are slipped into a “V”
shaped opening in the scale. The number that comes the
nearest to the center of the wire or screw being measured,
gives the correct gauge.
Figure 2
3. The micrometer caliper. — This tool is used to measure the
diameters of objects in thousandths of an inch. The illustra-
tion given in figure 2 shows the method of measuring and
names the major parts of the tool. The micrometer, in con-
junction with a table showing wire sizes and diameter in
thousandths of inches is frequently used as a wire gauge.
The instructor will demonstrate the use of this tool.
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Lesson 3
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4. Speed indicator. — This tool is used to determine the
revolutions per minute (rpm) of motors and shafts revolving
either clockwise or counterclockwise. There are several types
of this instrument, the one usually encountered in the Signal
Corps being the 1-16. The instructor will demonstrate its use.
5. Tapes. — Tapes are flexible measuring devices, laid off in
fractions of an inch, inches and feet. The most common
lengths are the 6 ft, 50 ft and the 100 ft tapes. These tapes
are furnished in three grades; the cloth tape of woven cotton
or linen, the metallic tape, which is doth interwoven with
metal strands; and the steel tape which is a high grade
metal ribbon. The steel tape is the most efficient, being
little affected by temperature changes, does not stretch and
is very durable. Care should be exercised to keep the steel
tape flat when using it since a kink may cause it to break.
6. Thickness gauges. — The thickness gauge is a steel leaf,
with its diameter in thousandths of an inch stamped on one
surface. This type of gauge is used to measure small air gaps
between relay springs, gear teeth, armatures and cores, etc.
The correct gauging of a gap is obtained by using a gauge
leaf that touches each side of the gap without moving either
of the two parts, or, is tight without sideplay or bind. A
sensitive touch must be acquired in order to obtain the
correct reading of clearances.
Review questions. —
1. Name one use of the steel scale.
2. What is the wire gauge used for?
3. What part of an inch is a mil?
4. Which wire has the greater diameter, No. 10 or No. 22?
5. What is the smallest measurement that can be made
with the micrometer caliper?
6. What is the name of the instrument used to count rpm’s
of shafts and motors.
7. Which is the most accurate tape, metallic or steel?
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Measuring and Gauging
Lesson 3
8. What is the thickness gauge used for?
Note . — In order to determine the area of a given cross sec-
tion of wire, square the diameter as given in mils. For
example, it is desired to know the area in circular mils of
the cross section of No. 0000 B&S copper wire. By reference
to table I, the diameter is found to be 0.46 inch. This is equal
to 460 mils. 460 2 equals 211,600 circular mils, the area of
tiie cross section.
TABLE 1
DIFFERENT STANDARDS FOR WIRE GAUGES IN USE
IN THE UNITED STATES
(Dimensions of sizes in decimal parts of an inch)
. forming- Washburn
No. of m f rtcan ham, or & Moen English Stubs
wire Mfg . Co. legal steel
gauge go y iron or Standard wire
wire Roebling
V S Stand-
ard gauge
for sheet
and plate
iron and
steel
No, of
wire
gauge
000000
0.464
0.46875
000000
00000
.432
.4375
00000
0000
0.46
.4540
0.3938
.400
.40625
0000
000
.40964
.425
.3625
.372
.375
000
00
.3648
.38
.3310
.348
.34375
00
0
.32486
.34
.3065
.324
.3125
0
1
.2893
.3
.2830
.300
.0227
.28125
1
2
.25763
.284
.2625
.276
.219
.265625
2
3
.22942
.259
.2437
.252
.212
.25
3
4
.20431
.238
.2253
.232
.207
. 234375
4
5
. 18194
.22
.2070
.212
.204
.21875
5
6
. 16202
.203
.1920
.192
.201
.203135
6
7
. 14428
.18
.1770
.176
.199
.1875
7
8
. 12849
.165
.1620
.160
.197
.171875
8
9
.11443
.148
.1483
.144
.194
. 15625
9
10
. 10189
.134
.1350
.128
.191
. 140625
10
11
.090742
.12
.1205
.116
.188
.125
11
12
.080808
.109
.1055
.104
.185
. 109375
12
13
.071961
.095
.0915
.092
.182
.09375
13
14
.064084
.083
.0800
.080
.180
.078125
14
15
.057068
.072
.0720
.072
.178
.0703125
15
16
.05082
.065
.0625
.064
.175
.0625
16
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Lesson 3
Shop Work
TABLE 1 (continued)
DIFFERENT STANDARDS FOR WIRE GAUGES IN USE
IN THE UNITED STATES
(Dimensions of sizes in decimal parts of an inch)
No. of
wire
gauge
A tnerican
or Brown
& Sharpe
Co.
Binning - Washburn
ham, or & Moen English Stubs
Stubs Mfg. Co. legal steel
iron or Standard wire
wire Roebling
U S Stand-
ard gauge
for sheet
and plate
iron and
steel
No. of
wire
gauge
17
.045257
.058
.0540
.056
.172
.05625
17
18
. 040303
.049
.0475
.048
.168
.05
18
19
.03589
.042
.0410
.040
.164
.04375
19
20
.031961
.035
.0348
.036
.161
.0375
20
21
.028462
.032
.03175
.032
.157
.034375
21
22
.025347
.028
.0286
.028
.155
.03125
22
23
.022571
.025
.0258
.024
.153
.028125
23
24
.0201
.022
.0230
.022
.151
.025
24
25
.0179
.02
.0204
.020
.143
.021875
25
26
.01594
.018
.0181
.018
.146
.01875
26
27
.014195
.016
.0173
.0164
.143
.0171875
27
28
.012641
.014
.0162
.0149
.139
.015625
28
29
.011257
.013
.0150
.0136
.134
.0140625
29
30
.010025
.012
.0140
.0124
.127
.0125
30
31
.008928
.01
.0132
.0016
.120
.0109375
31
32
.00795
.009
.0123
.0108
.115
.01015625
32
33
.00708
.008
.0118
.0100
.112
.009375
33
34
.006304
.007
.0104
.0092
.110
.00859375
34
35
.005614
.005
.0095
.0084
.108
.0078125
35
36
.005
.004
.0090
.0076
.106
.00703125
36
37
.004453 .
.0068
.103
.006640623
37
38
.003965 .
.0060
.101
.00625
38
39
.003531 .
.0052
.099
39
40
.003144 .
.0048
.097
40
24
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UNIVERSITY OF CALIFORNIA
Measuring and Gauging
Lesson 3
LESSON 3
LABORATORY
Tools and materials. —
Combination wire and screw gauge Speed indicator, 1-16
Wire gauge, American standard Micrometer caliper
Thickness gauge *Wire, screw and plate
Steel scale samples
Items marked * are not placed on the memorandum receipt.
Procedure. —
Operation 1 . — Examine the steel scale, and record in the
space below the different graduations on its edges.
Ins. check
Operation 2 . — Use the wire gauges furnished. Measure
the wire samples and record the results in the space below.
Measure the screw samples, as to length and gauge. Record
results in the space below.
Screws
Wires Length Gauge No.
1 1 .
2 2
3 3
Ins. check
Operation 3 . — Measure the wire and plate samples with
the micrometer caliper. Record the results of the operation
below. Compare your measurements with the ones shown
on the attached chart. Check the gauge thus determined
with those. The instructor will demonstrate the use of this
instrument.
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losson 3
Shop Work
Diameter in mils Ga. Thickness in mils Ga.
1 X
Wire 2 Plate 2
Samples 3 Samples 3
Ins. check
Operation 4 . — Examine the speed indicator. The instruc-
tor will demonstrate the use of this instrument. Find the
rpm of motor mounted on work bench. Record result below.
Ins. check
Operation 5 . — Examine the thickness gauge furnished.
Measure the air gaps of one of the sample sets on the bulle-
tin board, and record the results below.
A B C (Underline the set used)
1 2
3 4
Ins. check
26
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Metal Working
Lesson 4
LESSON 4
METAL WORKING
1 . files. — A file is a tool used for smoothing and shaping
hard materials such as brass, copper, iron bakelite, etc. Files
are classified according to length, measured from the shoul-
der to the point, by shape, and by the cut. There are twelve
standard file shapes, the most common being, flat, half
round, round, triangular and square. The lengths usually
run from 2 to 14 inches.
Cuts of files . — This classification, which pertains to the
teeth of a file, has three subdivision, single cut, double cut
and rasp, which are illustrated in figure 1.
(»)
(b)
TL-3262
Figure 1
File teeth .— The cut of a file is also classified according
to the coarseness of the teeth as rough, coarse, bastard,
second cut, smooth and dead smooth. Do not confuse the
term “second cut,” which applies to the size of the teeth,
27
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Lesson 4
Shop Work
with the term “double cut” which refers to the kind of teeth.
Selecting the file . — The proper file to use for any given
job depends on a number of factors; the ones listed below are
general rules only.
The type of metal, whether cast or wrought. Cast metals
are the hardest to cut and a new file should be used if
possible.
The shape of the piece to be smoothed. Use a file that
will reach sill parts of an irregularly shaped piece. As an
example, a slitting file would be the correct shape for a
diamond shaped opening; an equaling file is the best shape
for a narrow slot; a flat file is the best for squaring ends
and surfaces.
The area of the surface being dressed. A large surface
should be brought to shape with a rough or course file of a
large size. Smaller pieces should be shaped with smaller files
in either the bastard or second cut grade of teeth.
The degree of accuracy required. The bastard file is the
best for general use where the fit tolerance is not so critical
and the appearance of the finished work is not important.
For close fits and where it is desired to prepare the work for
buffing or polishing, the final shaping should be done with
the second cut or smooth file. The dead smooth file is seldom
used.
A flat file is not exactly fiat, but slightly convex on both
sides. This concentrates the pressure on a few teeth in the
center of the file, reducing the amount of force required to
move the tool over the piece. This gives the operator better
control over the file.
Hand filing is a difficult job. It requires considerable skill
and patience. The beginner will find that the slower he runs
the file over the work, the less chance there is of rounding
the corners of the piece being squared. Some general rules
for the use of the file are given below:
Select the proper shape, size and cut of file.
Always use a file handle; this gives the user the best
control of the file.
Apply pressure on the forward stroke only. The teeth are
28
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Metal Working
Lesson 4
not supported by the body of the file on the backstroke.
Pressure in this direction breaks the teeth and the file soon
becomes useless.
Assume a natural position and use as long a stroke as
possible.
The work should be held securely, and if in a vice, should
be below the line of the workman’s elbow.
The file should be held firmly and an effort should be
made to apply an equal amount of pressure with each hand.
Keep the file free of cuttings. This is best done with a file
card, which is simply a flat wire brush. Copper and tin, also
lead to a certain extent, have a tendency to clog the file
teeth. This may be reduced by rubbing chalk over the file.
The file needs more care than it normally gets. Keep it
free from rust, do not drop it across other tools and do not
carry it loose in a tool bag.
2. Hacksaws. — The hacksaw is a metal frame used to hold
blades specially made for the cutting of metals and other
hard materials. The frame is usually adjustable to accommo-
date the various lengths of blades. It is equipped with two
pin spindles to hold the blades under tension, the one on the
handle being equipped with a knurled sleeve. This locks the
blade in place after the proper tension has been placed on it,
by turning the handle. Examination of the spindles will dis-
close the fact that they may be moved to various positions
in the frame. This permits the blade to be turned at right
angles to the frame which is necessary for some classes of
work.
There are two grades of hacksaw blades, coarse and fine.
The coarse blades are used for general work and the finer
blades to cut thin plate, sheet metal, thin walled tubes and
small rods. The teeth of the hacksaw blade are given set to
prevent the blade from binding in the cut. To insure a
straight cut and ease of operation, the following rules should
be observed:
Insert the blade with the teeth pointing away from the
handle, turn the handle until the blade is tight and run the
sleeve down to prevent it from slipping. ,
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Lesson 4
Shop Work
Apply pressure on the forward stroke only.
Use a long slow stroke; do not force the cut.
Hold the work securely. Have the cut as close to the point
of support as possible.
3. Hand drill*.— The hand drill is a tool used for driving
twist drills. Hand drills are made with various chuck capaci-
ties, the 14 and % inch being the ones most commonly used.
Some hand drills are equipped with a speed change, ratchets
for working in close quarters, and a lock to hold the gear
assembly steady while tightening or loosening the chuck.
The chuck of the hand drill is of the three jaw type and is
designed to hold drills with round shanks only. The chuck
is tightened by hand only. Do not use a vice or wrench.
4. Twist drills. — The twist drill is a tool designed to bore
holes in practically any material. Small twist drills usually
have a round shank for use with the three jaw chuck. There
are three classes of drills in common use: the wire gauge
series, numbered from 1 to 80; the lettered series A (.243)
to Z (.413) ; and the series that begins at l/64th of an inch
and increases in size by 64ths to *4 inch. The twist drill for
general work is made of carbon steel, those used for pro-
duction work and drilling in the better grades of steel are
made of high speed steel.
A twist drill, in order to bore a perfectly round hole,
should have both lips ground at the same angle and be of
equal length. The angle should be about 60 degrees. Drills
should have a lip clearance of 10 to 15 degrees to insure the
lip biting the material without interference. See figure
3.
30
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UNIVERSITY OF CALIFORNIA
Metal Working
Lesson 4
Figure 3
The important points to be remembered when drilling are:
the speed with which the drill is turned and the rate at which
the drill is fed into the material. A good general rule to fol-
low is, the harder the material the slower the speed and the
lighter the feed. This does not apply to bakelite and similar
thermo (heat) setting materials. These materials, although
they are comparatively soft, clog the drill and heat rapidly
unless a slow feed and speed is used. A lubricant, such as
lard oil, turpentine or castor oil, should be used to preserve
the temper of twist drills. Never use a mineral oil for a
cutting oil.
5. Center punch. — The center punch is a steel rod (usually
knurled), with one end tapered to a 60 degree tempered
point. It is used to dent material prior to drilling. The dent
acts as a guide for the point of the drill. This prevents the
drill from wandering or taking hold at a place other than the
center of the proposed hole. It is not necessary to strike a
center punch hard. Tilt the top of the punch to one side,
place the point at the site of the proposed hole, raise the
punch to the vertical and strike the top once with a light
hammer.
465422 O-42-S
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Lesson 4
Shop Work
Bottoming
TL-3292
Figure 4
6. Taps and dies. — The tap is a hard steel tool used to cut
internal threads. The three kinds of taps are: the taper tap,
used where the tap can be run completely thru the hole; the
plug tap, used where it is desired to thread a hole which
does not run thru the stock; and the bottoming tap, which is
used to thread the full depth of the hole. Taps are highly
tempered and therefore very brittle. Great care to avoid
lateral stresses must be exercised to prevent breaking the
tap. A tap broken off in the hole, particularly if broken
i.U is
32
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UNIVERSITY OF CALIFORNIA
Metal Working
Lesson 4
Ficure 5
flush with the surface, causes a great deed of extra work.
In using the tap, see that it starts straight; this can be
checked with the square. After it is started, check it again
and if the tap is running slightly crooked, make the attempt
to straighten it while turning and not when the tap is stand-
ing still. Turn the tap several revolutions to the right and
then to the left about a half turn. This prevents the tap
from binding, which might cause it to break. In tapping
thin brass and bakelite, no lubrication is necessary; for
heavy or hard materials, the same lubricants as used for
drilling are satisfactory. The tap is held in a special tool
called a tap wrench. See figure 4.
The die is a tool used to cut outside threads. It consists
of a screwplate, two adjusting screws and a set of thread
cutters. The screwplate has a hole in its center which is the
size of the outside threads and acts as a guide. The cutters
are tapered so that the cut is made gradually, in the same
manner as the tap. The threading operation must always
be started from the screwplate side. Wear on the cutters
may be compensated for, within a small limit, by use of the
adjusting screws. A lubricant should be used in the same
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Lesson 4
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manner as specified for taps. The die is held in a special
tool called a stock. See figure 5.
Figure 6
7. Abrasives. — There are a great many tools and materials
used to smooth and polish metals, plastics, bakelite or other
hard substances. Emery cloth, which consists of powdered
emery, glued to a strong doth, is the abrasive most used to
remove tool marks and polish hard metals such as iron and
steel. The grades in common use are 000 to No. 2. The
emery cloth graded by zeros is considered fine; the greater
the number of zeros, the finer the doth. That graded in
whole numbers is considered coarse; the larger the number
the coarser the cloth. In the finer polishing operations, lard
oil used with emery cloth, produces an excellent finish. A
still finer finish is procured if flour is used. Never use emery
or carborundum on soft metals such as copper and brass.
The particles of abrasive will break off and imbed in soft
metals and cannot be removed.
Crocus doth is a heavy doth faced with jewelers’ rouge.
It is primarily an abrasive for soft metals, but is useful as a
finisher for hard metals. Another use for crocus doth is the
brightening of a commutator of a motor where the least
possible amount of material should be removed without dan-
ger of leaving abrasives on moving parts.
8. Scribers. — The scriber is a tool used to layoff lines on
any hard material. It is simply a metal rod with a sharp
point on one end and may be anything from a commercial
article to a nail with the point ground down so that it will
make a fine line. The top of the scriber should be tilted away
from the square or scale when scribing a line, in order that
the dimension laid off will be as accurate as possible.
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UNIVERSITY OF CALIFORNIA
Metal Working
Lesson 4
9. Machine screws. — Machine screws are used to hold metal
or other hard material parts together. They are classified in
the following manner: length, type of head, number of
threads per inch, diameter of gauge and the material made
of. The common types of machine screw heads are illus-
trated in figure 6.
10. Nuts. — A nut is a piece of metal having a threaded hole
through its center and designed to screw on to the threaded
portion of a bolt or machine screw. Nuts are classified
according to their shape as square, hexagonal, etc. Nuts are
also classified according to the screw or bolt which they are
intended to fit. For machine screws, nuts are ordered by
specifying the material, shape, the gauge of the diameter
and the number of threads per inch, as nuts, hexagonal
brass 6-32.
11. The countersink. — On all flat-head machine screws,
the angle of the under side of the head is 82 degrees. There-
fore, when a flat head screw is used, the hole in which it fits
must be countersunk at the surface of the hole where the
the head of the screw fits. This allows a screw to be used in
a place where the surface of the work must remain flat. The
tool which makes this 82 degree hole is called a countersink.
They are made of steel and have a round or sqare shank. The
point is cut to a taper of 82 degrees. The cutting edges are
usually three or four in number. The flutes which lead to
the cutting edges are 60 degree, concave, angular grooves.
The back rake of the cutting edges are approximately 15
degrees. This is a good angle for most metals. The flutes of
a countersink are not cut back full length of the body as in
the case of a twist drill because a countersink never is used
deeper than about % inches.
Another type of metal countersink is used when a nut is
to be sunk below the surface. This small type of tool has
the same kind of cutting edges, but instead of a point, a
small pin is set into the end of the tool; also, the angle of the
cutters is a right angle to the axis of the tool. This tool
must be used with a given size hole which fits the pin of the
countersink. This type is made in various sizes and pin
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Lesson 4
Shop Work
diameters. Various types of countersinks are illustrated in
figure 7.
TAPER -
PIN
REAMER
TL-329I
The countersink is usually used in a hand drill provided
it has a round shank. If it is equipped with a square shank it
must be used in a brace.
Review questions. —
1. What is a file used for?
2. Name two cuts of files according to the coarseness of
the teeth.
3. What is used to clean the teeth of a file?
4. Which way should the teeth of a hacksaw point?
5. What important point should be remembered when
using the hacksaw?
6. How are files classified?
7. Name two important points to be remembered when
using the twist drill.
8. Name one solution used as a cutting oil.
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Metal Working
Lesson 4
9. What tool is used to mark the center of a hole prior to
drilling?
10. Name the three kinds of taps.
11. What tool is used to cut outside threads?
12. Name two materials used to polish metals.
13. Give the five classifications of machine screws.
14. What is the scriber used for?
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Lesson 4
Shop Work
LESSON 4
LABORATORY
Tools and materials. —
Files, assorted (3) Center punch
Hacksaw frame Tap and die set, AA-4
Hacksaw blades, fine and File card
coarse # Brass stock, y 2 x 1 inch
Try or combination square *Iron stock, y 2 xl inch
Hand drill * Sheet brass
Twist drill No. 35 *Iron plate
Twist drill No. 17 *Bakelite
Hammer, ball peen * 1 / 4-inch brass rod.
Items marked * are not placed on the memorandum receipt.
Procedure. —
Operation 1 . — Using the y 2 -inch x 1-inch brass stock, cut,
square the ends with the files, lay out the holes, drill and tap
the following figure. Refer to figure 4 before using taps.
Ins. check
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UNIVERSITY OF CALIFORNIA
Metal Working
Lesson 4
Operation 2 . — Cut a piece of the iron stock furnished,
iy 2 inches long. Square the ends with the files.
Ins. check
Operation S . — Cut a piece of sheet brass using figure 9(a)
for dimensions. Square the piece, layout the holes, drill and
tap as shown.
Figure 9
After this piece has been checked by the instructor, cut it
into two pieces 1*4 inches by 1 y 2 inches. Save these pieces as
they are to be used in a later lesson.
Ins. check
Operation k - — Cut a piece of the iron plate and square it.
Make the bracket shown in figure 9 (b) .
Ins. check
Operation 5 . — Cut a piece of bakelite 1 inch by 2*4 inches.
Square the piece. Use file emery doth furnished and smooth
the surfaces.
Ins. check
Operation 6 . — Use the brass rod furnished. Cut 1 inch of
threads on one end only.
Ins. check
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UNIVERSITY OF CALIFORNIA
Lesson 4
Shop Work
ANNEX LESSON FOUR
BASIC THREAD DIMENSIONS, TAP AND CLEARANCE
DRILL SIZES
Machine Screw Sizes — National Form
Nominal
She
Major
Diameter
Tap
Drill
Number
e
Clearance
Drill
Number
Decimal
Equivalent
of
Tap Drill
Decimal
Equivalent
of
Clearance
Drill
0-80
.0600
56
48
.0469
.0760
1-56
.0730
54
45
.0550
.0820
-64
.0730
53
45
.0595
.0820
-72
.0730
53
45
.0595
.0820
2-56
.0860
50
42
.0700
.0930
-64
.0860
50
42
.0700
.0930
3-48
.0990
47
37
.0785
.1040
-56
.0990
45
38
.0820
.1040
4-32
.1120
45
32
.0820
.1160
-36
.1120
44
31
.0860
.1200
-40
.1120
43
31
.0890
.1200
-48
.1120
42
30
.0935
.1280
5-36
.1250
40
30
.0980
.1280
-40
.1250
38
29
.1015
.1360
-44
.1250
37
29
.1040
.1360
6-32
.1380
35
28
.1100
.1400
-36
. 1380
34
28
.1110
.1400
-40
.1380
33
28
.1130
.1400
7-30
.1510
31
22
.1200
.1570
-32
.1510
31
22
.1200
.1570
-36
.1510
30
22
.1280
.1570
8-30
.1640
30
18
.1285
.1690
-32
.1640
29
18
.1360
.1690
-36
.1640
29
18
. 1360
.1690
-40
.1640
28
18
.1405
.1690
9-24
.1770
29
13
.1360
.1850
-30
.1770
27
13
.1440
.1850
-32
.1770
26
13
.1470
.1850
10-24
.1900
25
9
.1495
.1960
-28
.1900
23
9
.1540
.1960
-30
.1900
22
9
.1570
.1960
-32
.1900
21
9
.1590
.1960
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Metal Working
Lesson 4
Machine Screw Sizes — National Form (continued)
Nominal
Size
Major
Diameter
Tap
Drill
Number
Clearance
Drill
Number
Decimal
Equivalent
of
Tap Drill
Decimal
Equivalent
Of
Clearance
Drill
12-24
.2160
16
i
.1770
.2280
-28
.2160
14
i
-32
.2160
13
i
.1850
.2280
14-20
.2420
10
i
.1935
.2500
-24
.2420
7
i
.2010
.2500
16-18
.2680
3
9/32
.2130
.2810
-20
.2680
3
9/32
.2130
.2810
-22
.2680
2
9/32
.2130
.2810
Fractional Sizes — National Form
Nominal
Size
Major
Diameter
Tap
DriU
Number
Clearance
Drill
Number
Decimal
Equivalent
of
Tap Drill
Decimal
Equivalent
Of
Clearance
DriU
A-64
.0625
3/64
50
.0469
.0700
1
to
.0625
3/64
50
.0469
.0700
5/64-60
.0781
-h
44
.0625
.0860
-72
.0781
52
44
.0635
.0860
3/32-48
.0938
49
38
.0730
.1010
-50
.0938
49
38
.0730
.1010
7/64-48
.1094
43
31
.0890
.1200
i-32
.1250
3/32
29
.0937
.1360
-40
.1250
38
29
.1015
.1360
9/64-40
. 140(6
32
25
.1160
.1490
5/32-32
.1563
i
19
.1250
.1660
-36
.1563
30
19
.1285
.1660
11/64-32
.1719
9/64
14
.1408
.1820
A-24
.1875
26
9
.1470
.1960
-32
.1875
22
9
.1570
.1960
13/64-24
.2031
20
3
.1610
.2190
7/32-24
.2188
16
1
.1770
.2280
-32
.2188
12
1
.1890
.2280
15/64-24
.2344
10
i
.1935
.2500
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UNIVERSITY OF CALIFORNIA
Lesson 4
Shop Work
Fractional Sizes — National Form (continued)
Nominal
Size
Major
Diameter
Tap
Drill
Number
Clearance
Drill
Number
Decimal
Equivalent
of
Tap Drill
Decimal
Equivalent
of
Clearance
DriU
1-20
.2500
7
17/64
.2010
.2650
-24
.2500
4
17/64
.2090
.2650
A-18
.3125
17/64
21/64
.2656
.3281
-24
.3125
9/32
21/64
.2812
.3281
-32
.3125
19/64
21/64
.2968
.3281
i-16
.3750
A
25/64
.3125
.3906
-20
.3750
21/64
25/64
.3231
.3906
-24
.3750
21/64
25/64
.3281
.3906
*-14
.4375
1
29/64
.3750
.4531
-20
.4375
25/64
29/64
.3906
.4531
-24
.4375
25/64
29/64
.3906
.4531
1-12
.5000
27/64
33/64
.4218
.5156
-20
.5000
29/64
33/64
.4531
.5156
-24
.5000
29/64
33/64
.4531
.5156
*-12
.5625
31/64
37/64
.4843
.5781
-18
.5625
33/64
37/64
.5156
.5781
i-11
.6250
17/32
41/64
.5312
.6406
-12
.6250
35/64
41/64
.5468
.6406
-18
.6250
37/64
41/64
.5781
.6406
tt-H
.6875
19/32
45/64
.5937
.7031
-16
.6875
f
45/64
.6250
.7031
1-10
.7500
21/32
49/64
.6562
.7656
-12
.7500
43/64
49/64
.6781
.7656
p = pitch
d = depth
f = flat
42
Formula
p = 1/No. thds. per in.
- d = p X .64952
l f = P/8
Figure 10
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UNIVERSITY OF CALIFORNIA
Metal Working
Lesson 4
DECIMAL EQUIVALENT OF DRILLS NO. 1 TO 60
Lesson 4
Shop Work
DECIMAL EQUIVALENT OF
FRACTIONAL DRILLS 1/64 TO 1 INCH (continued)
Drill Size
Decimal
Drill Size
Decimal
5/32
.1562
21/32
.6562
11/64
.1718
43/64
.6718
A
.1875
tt
.6875
13/64
.2031
45/64
.7031
7/32
.2187
23/32
.7187
15/64
.2343
47/64
.7343
i
.2500
1
.7500
17/64
.2656
49/64
.7656
9/32
.2812
25/32
.7812
19/64
.2968
51/64
.7968
A
.3125
H
.8125
21/64
.3281
53/64
.8281
11/32
.3437
27/32
.8437
23/64
.3593
55/64
.8593
i
.3750
$
.8750
25/64
.3906
57/64
.8906
13/32
.4062
29/32
.9062
27/64
.4218
59/64
.9218
A
.4375
H
.9375
29/64
.4531
61/64
.9531
15/32
.4687
31/32
.9687
31/64
.4843
63/64
.9843
i
.5000
1
1.0000
44
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UNIVERSITY OF CALIFORNIA
Soldering
Lesson 5
LESSON 5
SOLDERING
1. General. — Soldering is the binding together of two or
more metals by means of a fusible alloy of tin and lead called
solder. The solder used in the operation must melt at a lower
temperature than the metals being joined together. How-
ever, the nearer the melting points of the solder and the
soldered metals, the stronger the completed joint.
2. Fluxes. — When a metal is heated, its surface combines
with the oxygen of the air, forming a substance called oxide.
A flux is used to prevent this oxide from forming when
soldering. If a flux were not used, it would be impossible to
solder a joint. Rust on a piece of iron is a kind of oxide.
There are two classes of fluxes, corrosive and noncorro-
sive. A corrosive flux is used when soldering galvanized iron,
zinc, iron and steel. Borax, sal ammoniac and zinc chloride
are corrosive fluxes. A corrosive flux should seldom be used
in electrical work, as it eats away the metal being soldered.
After using a corrosive flux, the joint must be thoroughly
cleaned to remove traces of the flux that are left on it, thus
preventing the flux from eating away any more of the ma-
terial. Stearine, rosin, and tallow are noncorrosive fluxes.
These are used when soldering copper, lead, tin, etc. A non-
corrosive flux prevents and cleans the oxide, when soldering,
without eating away any of the material. Rosin is the most
common noncorrosive flux. It may be in the form of a pow-
der, a liquid, or a paste.
A flux, to have a cleansing effect on a surface, must melt
at or below the fusing point of the solder and must prevent
any oxidation by excluding the air during the process of
soldering. Different substances solder better with different
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Lesson 5
Shop Work
fluxes, although rosin is the best all-around flux for general
use. The usual fluxes for common metals are as follows:
Noncorrosive
Aluminum Stearine
Brass Rosin
Copper Rosin
Lead Rosin, tallow, or
Stearine
Tin Rosin
Corrosive
Iron or steel Borax or sal
ammoniac
Zinc Zinc chloride
Galvanized iron Zinc chloride
3. Solder. — Solders are divided into two general classes,
hard and soft. Hard solders are usually used in brazing. They
are composed of silver and its alloys or other compositions of
the harder metals, and have a high melting point. Soft
solders are used for general soldering and electrical work.
They are composed of lead and tin. The types of soft solders
usually encountered in the Signal Corps are; a bar composed
of 50 parts tin and 50 parts lead used for general soldering
work; and a wire solder with a rosin core, which is very con-
venient to use when soldering small terminals, lugs, radio or
telephone parts.
4. Soldering irons. — The heat for soldering is generally sup-
plied by a soldering copper, commonly called soldering iron.
The soldering iron consists of a copper bit fitted with a suit-
able shank and handle. The bit of the soldering iron is made
of copper, because copper has a high thermal conductivity
and readily permits the heat to flow from the body of the
copper to its tip. In addition, copper tins readily. Different
size coppers are used for different kinds of work and are
classified according to their weight.
Soldering irons are heated by one of two methods, exter-
nally or internally. The externally heated iron is heated by a
gasoline blow torch or a gasoline furnace. The internally
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Soldering
Lesson 5
heated, or electric iron, is heated by an electric heating ele-
ment in the shank of the iron. The electric iron has two
great advantages over the torch heated iron. First, it is
easier to keep hot while in use. Second, it is easier to keep
from overheating. Overheating an iron oxidizes the tinned
surface, thus preventing the even flow of solder over the cop-
per surface. Overheating also causes the copper to become
rough and pitted. To solder efficiently, the point of the solder-
ing copper must be clean. To free the iron of tarnish and
oxide, the point is covered with a thin coat of solder. This
process is called tinning. The tinning is usually done on a
soft brick, with a part of the top hollowed out. To tin the
iron, proceed as follows:
Place a small amount of powdered rosin on one end of the
brick and some scrap solder on the other end. Heat the iron
with the blow torch.
File one side of the iron, immediately turn it over and rub
the filed side first in the rosin and then in the solder. Wipe
the excess solder from the point with a clean rag.
Continue filing and tinning each side in succession until
all four sides are tinned.
The iron must not be too hot for the best results. If it is
too hot, the solder will not stick. To prevent the destruction
of the tinning, when heating the iron for use, keep the point
of the soldering iron from direct contact with an open flame.
The electric iron is tinned on one side only. File the side
selected after the iron is hot and melt a small amount of
rosin core solder on the cleaned surface. Wipe off the excess
solder with a clean rag.
Usually the irons are made with a removable tip. It is very
important that the tip be removed from the element and that
both tip and tip socket are cleaned of all scale. This must be
done after every thirty hours of operation. This cleaning is
done to prevent the tip from sticking in the element.
If it becomes necessary to remove the element from the
iron, the following procedure should be followed:
Remove the tip.
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Lesson 5
Shop Work
Hold the element end of the iron in the left hand and
unscrew the handle with the right hand.
Slide the handle back on the cord.
Remove the two screws that hold the flat wires which
lead to the element.
Remove the element lock nut.
Slide the element case forward and off the element.
Remove the element by sliding it forward.
When renewing the cord of the iron, do not use any wire
other than heater cord , that is, a cord which has a covering
of asbestos on each wire.
5. The blowtorch. — The gasoline blowtorch consists of a
round, brass tank, an air pump and a burner assembly. The
tank is filled with gasoline through a filler plug in the bottom
of the tank. On top of the tank near the handle is the air
pump which keeps the fuel under pressure; also on top
and near the edge of the tank is the threaded vent for
the fuel supply tube. The fuel supply tube contains a wick
and also supports the burner assembly. The burner assem-
bly consists of a gas orifice, a needle control valve, a
vaporizing chamber and a perforated combustion chamber.
Just beneath the burner assembly is a priming cup. The pro-
cedure in placing the torch in operation is as follows:
Invert the torch and remove the filler plug. Use drift pin.
Fill the tank three-fourths full with ordinary gasoline. Do
not use high test gasoline and do not fill the tank complete-
ly full, because some space must be left for air pressure.
Replace the filler plug and place the torch in an upright
position. In replacing the filler plug do not use excessive
force. A little soap on the threads of the plug will help seal
the container.
Place the fuel under pressure with the air pump. Pump
until it works hard.
Hold palm of hand over the end of the combustion cham-
ber and open the needle valve slightly. This allows the fuel
to flow into the priming cup. Shut the needle valve when the
cup is % full.
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Soldering
Lesson 5
Light the gasoline in the priming cup and keep the flame
directed toward the combustion chamber.
Just before the fuel is completely burned out of the cup
open the needle valve. If the gas does not ignite hold a
match near the vent holes in the combustion chamber. Do
not hold the match at the end of the chamber.
To increase the flame increase the pressure in the tank
and adjust the needle valve. Avoid excessive pressure, be*
cause the flame cannot be controlled so well.
The purpose of burning fuel in the priming cup is to
thoroughly heat the vaporizing chamber. This causes the
liquid fuel to be turned into gas.
When using the torch to heat an iron do not let the
point come in direct contact with the flame. To do so will
necessitate retinning the point. A blow torch is seldom cared
for properly. This results in a great deal of unnecessary re-
pair work. Some general rules for the care of the torch are
given below:
After the priming cup has been filled, wipe any spilled gas-
oline from the other parts of the torch before lighting it.
When the gasoline is nearly consumed in the priming cup,
do not open the needle valve fast. If the torch is not hot
enough, this will cause a stream of flaming gas to leave the
combustion chamber, and create a fire or bum the user
seriously.
As the gasoline in the torch is consumed, more air is re-
quired. Pump the torch up occasionally.
Metal contracts and expands with changes of temperature.
When closing the needle valve, shut it down tight enough to
put out the flame and then turn it back a little to prevent
freezing.
6. Requirements for good soldering. — In order to do good
soldering, it is necessary that the following be observed:
The surface to be joined should be clean, it being impossi-
ble to make solder stick to a dirty or greasy surface.
The soldering iron should be cleaned and properly tinned.
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Lesson 5
Shop Work
The metals being soldered must be heated in order that
the solder will adhere to the surface.
The surfaces being joined should be as close together as
possible, with the least amount of solder between the sur-
faces. Too much solder means a poor joint.
The area of the joint being soldered should always be com-
paratively large to secure the necessary strength. With a
properly tinned iron and the proper flux, the success of any
soldering operation depends upon the cleansing of the sur-
faces to be joined and the heat applied to the joint during
the soldering operation. The heat which is applied depends
upon the speed with which the iron is drawn along the joint.
If the iron is moved too slowly, the solder tends to spread
too much and if moved too rapidly, the solder will not have
time to melt completely and the joint will not be filled with
solder. If heavy material is being soldered, the iron will have
to be moved more slowly than if the metals being joined are
metals whose melting point approaches that of solder. When
using an extremely heated iron, the position of the iron is
varied as the work progresses. When starting, the point of
the iron is used. As the iron cools, it is lowered so that more
of the flat tinned surface of the point is m contact with the
work. This is not so important with electric irons, as the
heat does not vary so greatly if properly used,
7. Soldering splices. — Half and half solder has an electrical
conductivity of about one-seventh that of copper. All splices
between conductors that are to carry current should have
the smallest possible amount of solder separating conductor's.
This means that the wires to be joined must be as close to-
gether as possible before the solder is applied.
There are two methods of soldering a splice. The first,
known as flowing, is to hold the hot iron on the top side of
the splice and run the solder into the joint. The second,
known as sweating, is to heat the joint from the under side
while the flux and the solder are applied from the upper side.
The wires melt the solder as soon as they become hot
enough, and the melted solder is drawn into the cracks be-
tween the wires. Sweating is the better method. When
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Soldering
Lesson 5
soldering a Western Union splice, it is soldered only in the
neck and not in the buttons.
8. Soldering flat surfaces. — When soldering two flat sur-
faces, such as two overlapping plates of metal, it is usually
desirable to tack the two pieces together at several points by*
drops of solder, before attempting to solder the entire length
of the seam. This will hold the two plates in position while
the main soldering is being done. When soldering one flat
piece of metal to another, they are usually sweated because
of the difficulty in getting solder into the joint. If the sur-
faces to be joined are first tinned, then placed in contact
with each other and heated, there is more chance that a
better joint will result, than if the solder is drawn into the
joint. To sweat such joints, the metals must be close together
after being tinned. If the surfaces are uneven, the sweating
process is not successful unless it is combined with soldering
in the ordinary manner. That is, the surfaces are first tinned,
placed in contact, and while being sweated, solder is applied
to the edge of the seam and drawn into the joint.
9. Using the electric iron. — The electric soldering iron is
delicate in construction and requires careful handling. When
soldering^ do not swing or jerk the iron to remove excessive
solder. This practice endangers men working nearby and
may damage adjacent equipment. Do not strike the iron
against a solid substance as this is likely to crack the heating
element and cause a breakdown of the insulation. When the
iron is not in use, always keep it in its holder.
10. Soldering large terminals. — Wiring that terminates at
power boards and other apparatus is generally sweated into
terminal lugs.
Terminal lugs, especially for the larger sizes of wire, usu-
ally have a cup socket at the bottom. When soldering a solid
or stranded wire into the socket, the preferable method is to
tin the end of the wire and fill the socket with solder; ordi-
nary methods, where the wire is placed in the socket and
the solder heated and run into the socket with the iron,
make it difficult to get the solder down in the plug. The
socket is then heated in the flame of the torch in the case of
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Lesson 5
Shop Work
large sockets, or with the iron for small sockets. When the
solder in the socket is hot, the tinned end of the wire is
inserted into the socket and the source of heat removed.
The wire should not be moved while the solder is cooling.
After the solder has set more solder may be worked in if the
socket is not full.
11. Soldering small terminals. — Small terminals are more
easily soldered with an electric iron. When soldering wires to
terminals, which are mounted near a sealing compound, such
as transformers, only enough heat should be applied to melt
the solder. Otherwise, the sealing compound will melt
and run over the work; but be sure to apply sufficient heat
Only a small amount of solder is necessary on small ter-
minal lugs to make the required joint. The use of too much
solder makes a messy and lumpy looking job. An improper
joint, one which will probably cause trouble, is where the
solder has sweated only to the wire, while between the wire
and the lug there is a flux which acts as an insulator. A con-
nection of this kind is due to one of the following causes:
A cold soldering iron; the soldering iron held on the work
an insufficient length of time; improper use of the iron; and
untinned or unclean lugs and wire. The iron should be held
on the lug and wire until both become hot enough to melt
the solder. This is one of the fundamental rules of good
soldering. A satisfactory job cannot be done if the solder is
run on a cold or improperly cleaned lug, even though the
iron is sufficiently hot and properly tinned.
Terminals and terminal punchings encountered in the
telephone work are usually small ones and are of various
shapes and sizes. The word “punching” means, that the kind
of terminal is punched from a sheet of metal. Punched ter-
minals are usually small and flat, though sometimes they
have been shaped to give clearance and accessibility. Other
terminals of a similar size are actually the ends of the con-
tact springs of relays, lamps and jack strips, keys and
switches of various types. Terminal punchings must have a
mounting to hold them in place. Some are mounted separate-
ly, or in groups of two or three, by means of screws or mere-
ly stuck into the wood frame of an instrument, telephone or
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UNIVERSITY OF CALIFORNIA
Soldering
Lesson 5
& '
Figure 1
switchboard. The greatest number are mounted in terminal
blocks. Standard terminal blocks are assembled to accom-
modate twenty circuits, having from two to six rows of
terminals with twenty terminals in each row, depending
upon the purpose they are to serve. The employment of
these blocks on main and intermediate distributing frames
is covered in another course. A single terminal punching and
the end view of the block in which this kind of punching is
mounted is shown in figure 1.
An end view of a horizontally mounted terminal block is
shown in figure 2.
Note 1 . — When blocks are mounted vertically switchboard
cable wires are brought in on the left side and under their
respective terminals.
Note 2 . — Wires are skinned, and scraped of enamel, so
that the insulation comes up to but not in the notch or hole
of a notched or drilled terminal.
Cross connecting wires not
pressed against fiber strips.
Termina/s fitted
into fiber
strips
TL-3268
Switchboard cab/e wires pressed
against fibre strip after be mg
passed thru bottom ho/es of
b/ocA before be/ng stunned and
so/dered
Figure 2
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Lesson 5
Shop Work
Types of improperly soldered connections are shown in
figure 3.
Wire cut off too dose
and not bent over ena
of terminal-
Wire exposed and shows
imperfect amalgamation
at sides and rop-
The above connections do not have sufficient
mechanical strength to withstand stresses
app/ied to the wire.
Exposed wire
i
1
Wire imperfectly im-
bedded in sotder
The exposed portion of bare wire should be
touched with a hot iron until the so/der flows
over all surfaces. If the wire is coated with
enamel, or is dirty, it must be cleaned.
Airspace
Pocket filled with black
enamel or rosin >
Air spaces and pockets filled with b/ack enamel
permit entrance of air which, in time, may
cause ox/dat/on o f wire and solder, weakening
the connection
Figure 3
Figure 4 illustrates places to apply solder on terminals.
When soldering terminal punchings and especially those
of terminal blocks, care must be exercised to prevent the
solder from running to any place except the spot where it
should be applied. On terminals extending horizontally or
downward this is not difficult. On terminals extending up-
ward it is almost certain that solder will run down the side
of the terminal if too much solder is applied. This will usually
result in circuit troubles and must be avoided.
The process of soldering small terminals of radio and tele-
phone equipment by sweating, except for some special rea-
son, is not practical or necessary. The greatest disadvantage
to its use is that sweating is too slow. The second objection
being that it requires more heat to sweat the joint. This
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UNIVERSITY OF CALIFORNIA
Soldering
Lesson 5
Solder either side \^ighfptore°than
Terminate Extending Horizontal
Terminate
Extending Upward
Terminate
Extending Downward
l
•n
Drilled or Punched
TL-JI7I
Figure 4
added heat will sometimes cause the compound or fibre in
which the terminals are set to melt and loosen the terminal.
The amount of solder usually required for small terminals
can easily be obtained by laying the end of a piece of rosin
core solder on the terminal so that the length of the solder
lying against the terminal extends over the spot where the
solder is required. Then place the tip of a properly tinned
and heated iron on the solder. As soon as the solder melts,
the piece of solder held in the hand is moved away from the
iron tip. As soon as the solder on the terminal is completely
liquid and is adhering to the wire and terminal as it did to
the iron tip, remove the iron by dragging it off toward the
terminal end. Allow the soldered joint to cool before attempt-
ing to move wire or terminal. Excess solder may be removed
by remelting it and flicking the excess off with a small wood-
en stick or toothpick.
All terminal blocks, relays, cable forms, or other equip-
ment that is underneath terminals to be soldered, must be
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Lesson 5
Shop Work
covered with canvas or cheesecloth before starting to skin or
solder the wires.
Review questions. —
1. What is meant by the term soldering?
2. Should solder melt at a higher or a lower temperature
than the metals being soldered?
3. Why must a flux be used when soldering?
4. Which is the most common noncorrosive flux?
5. What are the two classes of solder?
6. Which class should be used to solder tin, lead, and
copper?
7. What is the bit of the soldering iron made of?
8. What advantages does the electric iron have over the
torch heated iron?
9. What must be done to the point of the iron before it can
be used for soldering?
10. Should the blow torch be completely filled with gaso-
line?
11. Should high test gasoline be used in the blow torch?
12. Why is gasoline burned in the priming cup before the
torch is turned on?
13. What are four requirements for good soldering?
14. Which has the best electrical conductivity, 50-50
solder or copper?
15. What are the two methods of soldering?
16. Which of the two methods should be used in soldering
small terminals?
17. On which side should terminals extending downward
be soldered?
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Soldering
Lesson 5
18. Should the tinned point of an externally heated iron
be placed in the flame of the blow torch? Why?
19. Should the melting point of the flux be below or above
that of solder?
20. Which part of the Western Union splice should be
soldered?
21. Is the sweating process used in soldering small termi-
nals?
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Lesson 5
Shop Work
LESSON 5
LABORATORY
(Wire Students Only)
Tools and materials for operations 1, 2, 3, 4 and 5. —
•1 ea. Blow torch
1 ea. Pliers, 8-inch, side-cutting
•1 ea. Soldering iron, iy 2 lb.
1 ea. File, 10-inch, with handle
1 ea. File card
*4 pcs. Wire, copper, No. 10
*2 pcs. Brass sheet (from lesson 4)
*1 pc. Wire, copper, No. 6
*1 ea. Large terminal lug
* Bar solder, rosin core solder, rags, seizing wire.
Items marked * are not placed on the memorandum receipt.
Procedure. —
Operation 1. — The blow torch will not be taken to a work
bench while burning.
Check the blow torch for broken or missing parts.
Following the instructions in the lesson sheet, fill and light
the torch.
Have the operation checked by the instructor.
Ins. check
Operation 2. — Check the soldering iron. Make sure the
handle is serviceable.
Use the tinning jig furnished. Follow the instructions in
the lesson sheet and tin the iron.
Ins. check
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Soldering
Lesson 5
Operation S . — Clean and tin one end of each of the four
pieces of No. 10 copper wire. The tinned portion should be
about 3 inches long. This wire is tinned in the same manner
as the soldering iron, except that it is heated by the iron
instead of the open flame of the blow torch. Lay two pieces
of the wire together with the tinned ends overlapping. Seize
the wires with a few turns of seizing wire at each end of
the tinned part.
Solder this joint using the flow method.
Prepare the other two wires.
Solder this joint using the sweating method.
Note the difference between the two joints.
The best way to solder the joints in this operation is to
place a piece of scrap wood on each side of the wire and
place it in a vise in such a manner that the portion to be
soldered is out to one side. The scrap wood will keep the heat
from running into the vise and a better joint will be secured.
Ins. Check
Operation 4 - — Solder a butt joint with the two pieces of
brass sheet Use the information contained in the lesson
sheet and the illustration given in figure 5. Lay the pieces on
a piece of scrap wood for the soldering operation.
Figure 5
Ins. check
Operation 5 . — Use the No. 6 wire and the terminal fur-
nished. Follow the information in the lesson sheet and solder
the lug to the wire according to the illustration given in
figure 6.
Ins. check
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Lesson 5
Shop Work
Ins. check
After completing Operation 5, the student will return to
the supply room, all tools and materials left over.
Tools and materials for operations 6 to 16 inclusive. —
Report to instructor before drawing equipment for opera-
tions 6 to 16.
*1 ea. Terminal block frame
1 ea. File, with handle
1 ea. Soldering iron, electric (TL-117)
1 ea. Pliers, long-nose (TL-126)
1 ea. Pliers, diagonal (TL-103)
1 ea. Insulation stripper.
*2 pcs. 20-pr. switchboard cable
*2 ea. Brass rods, % inch x 12 inch
* Lacing twine
* Rosin core solder
* Rags
Items marked * are not placed on the memorandum receipt.
Operation 6 . — Clean and tin the electric soldering iron.
Ins. check
Operation 7. — All operations with the terminal rack will
be performed with the bottom of the rack on the work bench.
In this position, the parts mounted on the rack present the
same appearance as the parts of a switchboard or main
frame.
Clean all of the terminals on the frame. This is best done
by heating the terminals with the electric soldering iron and
flicking the excess solder from them with a small wooden
paddle.
Ins. check
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Soldering
Lesson 5
Operation 8 . — Lash a piece of the 20-pair switchboard
cable to the frame, with the braid of the cable about y 2 inch
below the vertical terminal block. Separate all of the pairs in
the cable and twist the ends of each pair together. Use the
following table and distribute the pairs, starting at the top
of the terminal block, with pair No. 1.
Colored Wires
Mate
Pair No. 1 Blue
No. 2 Orange
No. 3 Green
No. 4 Brown
No. 5 Slate
No. 6 Blue-White
No. 7 Blue-Orange
No. 8 Blue-Green
No. 9 Blue-Brown
No. 10 Blue-Slate
No. 11 Orange-White
No. 12 Orange-Green
No. 13 Orange-Brown
No. 14 Orange-Slate
No. 15 Green-White
No. 16 Green-Brown
No. 17 Green-Slate
No. 18 Brown-White
No. 19 Brown-Slate
No. 20 Slate- White
White
t
Note . — The color code given above is standard for all
types of coded switchboard cables, whether braid or lead
covered.
Ins. check
Operation 9 . — Place the pairs under their respective rows
of terminals. Hold the pairs tightly in place and at the same
time push each pair sharply back against the fibre strip, in
which the terminals sire mounted, with the blunt wood stick.
Then lay the % inch brass rod between the base of the block
and the back row of terminals, to hold the wires in place.
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Lay the other rod in the same position on the opposite sides
of the block and lash the protruding ends of the rods firmly
together with lacing cord. Pull all pairs tight so that there
is no slack between the cable butt and the terminal block.
Ins. check
Operation 10. — Separate the first pair of wires. Lay the
white wire across the edge of the mounting strip so that it
will be out of the way. Bend the coded wire into the notch of
the top terminal of the second row. The terminal rows are
counted from the front to the back of the terminal block.
The next step is to remove the insulation from the wire.
This may be done with either the long-nose pliers or the
insulation stripper. Do not start to remove the insulation at
the point marked on the voire by the notch of the terminal.
Drop down toward the end of the wire about y 8 of an inch
and remove the insulation for a distance of about 1 inch.
Hold the wire under the terminal and push the insulation
back until the part of the wire that goes into the notch is
uncovered. Remove all tarnish or enamel from the wire.
Wind the loose ends of the insulation tightly around the
wire in such a manner, that the insulation comes under the
terminal but does not enter the notch. Bend the bared part
of the wire into the notch and lay it across the top of the
terminal at an angle of 45 degrees toward the rear of the
terminal block. It is necessary to leave the insulation long
and push it back on this type of wire, otherwise when the
iron is used to solder the connection the loose ends will
unravel and this might cause a short circuit.
Solder the connection and inspect each separate connec-
tion for the faults listed below:
a. Insulation in notch of terminal.
(Connection must be unsoldered and insulation pushed
back.)
b. Chalky solder. (Not enough heat)
c. Rosin core joints. (Not enough heat)
d. Solder not adhering to wire.
(Must be unsoldered and wire scraped.)
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Soldering
Lesson 5
e. Wire not laying against terminal.
(Hold wire tight, melt solder and let solder set before
releasing wire. )
After the connection has been inspected, and all faults
corrected, cut the excess wire off as close to the terminal as
possible. If the student is in doubt as to whether the con-
nection has been soldered properly, have the instructor
check it before soldering others. Continue with the coded
wires until all 20 have been soldered.
Ins. check
Operation 11 . — Solder the white wires to the first row of
terminals on the block.
Ins. check
Operation 12 . — Lash another piece of switchboard cable
to the left and at the back side of the terminal block mount-
ed horizontally. Place and solder the wires using the same
method as that for the vertically mounted block, except that
wires are wrapped from left to right so that the soldering is
done on the right side of the terminal. When finished and
checked for faults, submit to the instructor for approval.
Ins. check
Operation 13 . — Run three pairs of lacquered cross-con-
necting wires from the vertical to the horizontal terminal
block. These wires are run on the opposite side of the blocks
from the cable. This wire is not dressed back against the
fanning strip. Each pair of cross connecting wires should
have approximately 3 inches of slack. Solder the white wire
to the first row of terminals and the colored wire to the
second row. Check the connections for faults and submit to
the instructor for approval.
Ins. check
Operation Ilf . — Solder a piece of scrap wire at least 6
inches long to each drilled terminal on the lamp strip.
Ins. check
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Operation 15 . — Solder a piece of scrap wire at legist 6
inches long to the center terminal of each group on the jack
strip. Submit to the instructor for approval.
Ins. check
Operation 16 . — Solder a piece of wire to each of the ter-
minals of the 5-pair section of vertical protectors. The in-
sulation of the wire should come up to, but not enter the
notch. In no case will the distance between the notch and in-
sulation exceed 1/16 of an inch. When attaching wire to
this type of terminal proceed as follows: Remove insulation
at the proper point, grasp wire at the end with a pair of long-
nose pliers and make one complete wrap around the ter-
minal, starting with the wire in the notch. Upon completion
of this wrap, bend the free end of the wire down along the
face of the terminal and cut it off within 1/32 of an inch of
the bottom. Solder the connection on the face of the ter-
minal.
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Wiring of Radio Equipment, Cords and Plugs
Lesson 5A
LESSON 5A
WIRING OF RADIO EQUIPMENT, CORDS AND PLUGS
(For Radio Students Only)
1. Bus wiring. — Bus wire for radio equipment is usually
No. 14 B&S gauge, or larger tinned copper wire. This wire
may be round or square. Heavy, enameled copper wire may
also be used for bus wiring. The tin or enamel coating on the
bus wire prevents corrosion and in the case of the tinning,
simplifies soldering.
Bus wire is used where a large current or a high fre-
quency current is to flow through the wire. Bus wire makes
a very strong job mechanically, however, if there is any
danger of it coming in contact with other wires in the set,
it should have some sort of insulation placed over it.
There are two methods of joining one piece of bus wire
to another. The butt joint and the loop joint. See figure 7.
Butt Joint Loop Joint
TL-J272
Figure 7
In the butt joint, one end of the wire to be soldered
to the other is bent to a right angle to form an “L.” The
bent over part should be from one-foiirth to three-eighths of
an inch long. The bend must not be too sharp or the wire
will be broken. Solder is then run in between the wires, a
small amount of solder is built up on the joint. This type of
joint is usually used when wiring with square bus wire.
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The loop joint is used when wiring with round bus wire, or
with enameled wire. This joint is made by bending a small
loop on the end of the wire to be fastened to another wire,
then this loop is placed over the wire and clamped in place
with a pair of pliers. The joint is then soldered. The solder
must be run in the loop.
Comparison of the two connections show the loop joint
to be much stronger them the butt joint as the loop joint
has added strength, because one wire is actually clamped
around the other. The strength of the butt joint depends on
the solder only.
When enameled wire is to be used, the enamel must be
removed from the wire before soldering. A fine line should
be scribed around the wire, then the enamel scraped off
from that point to the end of the wire. This makes a neat
job. When making a joint in the middle or part other than
the ends, two lines are scribed and the enamel removed
between these two lines.
Completed
Figure 8
2. Loop bending. — It is sometimes necessary to bend loops
where a wire is to be fastened around a screw. This is best
accomplished with the aid of a pair of long-nose pliers. The
loop is made by holding the extreme end of the wire in
the points of the pliers, the left thumb resting on the
wire and partly on the points of the pliers. Make a slight
bend on the end of the wire, the amount of this bend
will depend on the size of the loops required. Move the
pliers slightly back on the wire and make another bend,
continue until the loop is completely formed. Place the
pliers at A, as in figure 8, shape the loop to look like the
figure marked “completed loop.”
A loop in stranded wire is made in the same manner; how-
ever, it is necessary to dean and twist the strands together,
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Wiring of Radio Equipment, Cords and Plugs
Lesson 5A
then tin the wire before a satisfactory loop can be com-
pleted.
3. Cable wiring. — Cable wiring is used where a number of
wires follow the same path. The wires are laced into a
form, either before or after being soldered to their respec-
tive terminals, depending on the type of work being done.
The wires are laced together with the lock stitch, illustrated
in figure 9. Do not use a. half -hitch. This knot will not hold
the form together if the lacing cord is broken.
Figure 9
Note the points on the diagram in figure 9 marked “A”
and “B.” At these points the twine must be on the under side.
If either “A” or “B” is on top when the stitch is made, it
is called a half-hitch stitch. When the half -hitch is used it
will come loose if the twine is broken.
A figure eight knot is used to start the lacing. The short
end of the cord should be carried under the first two
stitches and then cut off. When the cable lacing is com-
pleted, the twine is anchored by placing two or three stitches
behind the last stitch of the form. See figure 10.
Figure 10
Do not lace wires carrying high voltage or high frequency
currents in a cable form with other wires.
A type of wire, called “pushback” is normally used to
wire radio sets. It is simply a tinned copper wire with an
insulation that can be easily pushed bade from the end.
This saves time and gives the installation a neat appearance.
Shielded wire is usually grounded to the frame of a set or
if used externally in vehides, to the body of the vehide.
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This is accomplished by either soldering a pigtail and lug
to the shield or unraveling the strands of the shielding,
twisting them to form a wire, and soldering this to the
nearest ground. If the ground is not near enough to the
point of termination to use this method, solder a piece of
stranded pushback wire to the shield and run it to the
ground.
4. Cords and cordage.— -
Definition . — Cordage is the bulk cable used in the fabri-
cation of cords. Cords are pieces of cordage cut to the
proper length and with the ends prepared for the application
of plugs. They may be prepared with or without the proper
plugs.
Use . — There are many types of cords used in the installa-
tion of radio sets. Cords are used to interconnect the com-
ponent parts of radio sets in aircraft, portable and vehicular
installations. The type of cord to be used is determined by
the particular installation and is covered by instructions
for the installation of each different type of equipment.
Description . — Cordage in general has from 2 to 8 con-
ductors, each conductor having an insulating cover of rub-
ber. The conductors are twisted together, jute or cotton
packing being added to give shape to the cord, and covered
with an insulating tape which, in turn, usually is covered
by the shield. The shield is composed of small tinned copper
wires braided around the taped conductors. The shield is
covered with a rubber jacket which insulates and protects
the entire assembly. In some cases the shield is on the
outside of the rubber jacket. This last type of cordage is
used extensively in aircraft and vehicular installations
where bonding of the cords at frequent intervals is es-
sential. The conductors in cordage are generally color
coded, each conductor having a different color rubber in-
sulation to facilitate the tracing and connecting of the con-
ductors. When the conductors are not coded, an ohmmeter
or some similar means must be used in tracing the conduc-
tors. Cords, in most cases, are fitted with plugs which fit into
sockets on the equipment thus making the necessary con-
nections between the units. This is not true in all cases
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Wiring of Radio Equipment, Cords and Plugs
Lesson 5A
however. In some equipment the cords are connected to
terminal strips in the units.
Common troubles . — One of the most common troubles
to be found in cords is the breakage of conductors at or
near the plugs or at points where the cord is bent too sharply,
as in going around the comer of some piece of equipment.
A cord should be long enough so that no strain is placed on
it at any time. Another common trouble is twisting of the
cord in the plug, thus shorting or breaking the conductors
in the plug. Be sure the plug is properly clamped on the
cord.
5. Plugs and sockets. —
Use and description . — Plugs are used on the ends of most
cords to facilitate the connecting of the cords to the units.
The plugs fit into sockets which are usually mounted in the
various units of the equipment. There are so many different
types of plugs and sockets that no attempt will be made to
describe them in this lesson, as the student will become
more familiar with the various types as he works with
the equipment. Most plugs and sockets have the connecting
pins so positioned that the plug can only be inserted into
the socket in the correct position. Most plugs are also
equipped with some locking device to prevent the plug
from being pulled out of the socket accidentally. Plugs and
sockets usually have the pins and connections numbered
or marked in some manner so that they may be properly
connected. The wiring diagrams of the equipment shows
these numbers or markings so that trouble shooting and
repair of the equipment is simplified.
Common troubles . — One of the most common troubles
found in plugs and sockets is poor connections between the
plug and socket. One type of socket commonly used has
banana plugs for the socket pins. The springs on these pins
become compressed and fail to make a good connection.
This may be cured by spreading the springs with a small
screwdriver or a scriber. Plug shells frequently become so
battered from dropping and other abuse that they do not
fit the sockets properly. If not too badly damaged they may
be reshaped and continued in service. The locking devices
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sometimes become damaged through accident or abuse. If
not too badly damaged they should be repaired and con-
tinued in service.
(c) JL'3276
Figure 11
6. Repair of cords. — The following information on the re-
pair of cords is necessarily of a general nature. The instruc-
tion books covering the different types of equipment and
the installation of the units usually covers the makeup of
the associated cord. In all cases these instruction books
should be consulted and local instructions followed when
repairing or making cords.
Preparation of cords . — Rubber jacketed cords will be con-
sidered in this lesson since this is the most commonly used
type. The first step is to cut the cordage to the proper
length. If an old cord is being used or repaired the conduc-
tors should be checked for continuity with an ohmmeter or
by some similar means. Next cut off the rubber jacket for
about 1 inch being very careful not to cut into the shield.
Diagonal pliers are the proper tool to use in cutting off
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Lesson 5A
the jacket. Tin the shield for a space about Vs -inch wide
next to the rubber jacket. Refer to figure 11a.
The next operation is to solder the ground lead to the
shield, where the shield was tinned. Remove about 1%-inch
of insulation from one end of a 6-inch piece of No. 18
stranded, rubber covered wire. Wrap the bare end around
the tinned portion of the shield and solder into place. Be
sure it is well soldered. Next cut the shield off back to the
tinned portion at the same time removing the insulating
tape and cutting out the cotton or jute packing cords. Be
careful not to cut the insulation on any of the conductors.
Now the insulation may be removed from the ends of the
conductors and the ends tinned. Do not remove too much
insulation, an eighth of an inch being sufficient in most
cases. The insulation on the conductors is usually live
rubber and unless extreme care is used too much insulation
may be pulled off. Do not use a knife to remove the insula-
tion. Nip it loose with the points of the diagonal pliers.
Twist the strands of each conductor together neatly and
tin them as soon as the insulation is removed. As soon as
this operation is finished the end of the cord will be served
with waxed lacing twine. The Signal Corps type number of
the twine generally used for this purpose is RP-13. The
following explanation and figures lib and 11c will show
how this serving is applied.
A piece of twine about 18 inches long is used. One end of
the twine is laid along the cord in a loop as shown by ABC
in figure 11c. Leave end of twine A about 4 or 5 inches
long and end of loop B about 1 inch back from the end
of the jacket. Beginning at C wrap 3 or 4 turns of twine
around the conductors drawing the twine very tight. Do
not include the ground lead when making these first 3 or 4
turns. Now include the ground lead and continue wrapping
the twine until about 4 turns are made over the rubber
jacket. Keep the twine pulled tight at all times and keep
the turns as close together as possible. Make the serving
look as neat as you can by working the turns, into place
with the fingers, as they are put on. Now put the end of
the twine D, figure lib, through the loop B. Pull on end A
pulling loop B under the wrapping as shown in figure 11c.
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This draws the end D under the wrapping at the same time
and thus ties the serving in place without the use of knots.
Cut off the ends A and D close to the wrap and the job
is finished.
Preparation of plugs . — The plugs should be inspected to
see that they are of the proper type and are clean and free
from corrosion. If old plugs are to be used, the old solder
should be removed and the plugs thoroughly cleaned. When
removing solder from the plugs having the pins or jacks
permanently fastened into a bakelite block, care should be
exercised not to use too much heat as this causes the bake-
lite to swell and the shell will no longer fit over it. Too much
heat also causes the bakelite to break down and results in
electrical leakage between the pins. See that all screws are
in place and have lock washers on them, and that the lock-
ing device is not damaged.
Soldering . — When soldering the conductors into the plug
do not hold the soldering iron on the connection too long.
As stated previously, this will cause trouble during and after
assembly. Be sure that the necessary plug parts are threaded
on the cord, before soldering the plug in place. Check your
wiring diagram and color code thoroughly before starting
to solder the conductors. Double check all connections while
soldering. If there is any doubt as to the colors of any of
the conductors, use an ohmmeter or some similar means to
check them through. Do not use too much flux or solder.
Surplus flux and solder should be cleaned from the con-
nections and plugs. Be sure that all strands of the conduc-
tors are soldered into place. Free strands may cause short
circuits or grounds. See that the insulation is not damaged
on the conductors. If necessary, insulating tape or doth
should be used to insulate the conductors.
Assembly of cords and plugs . — When all connections have
been soldered and inspected, the plugs may be reassembled.
When fitting the plug parts together be sure that the conduc-
tors are not pulled tight or twisted together any more than
is absolutely necessary. See that all the screws used in the
assembly have lock washers on them. Be sure that the lock-
ing device is free and operates properly. See that the cord is
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Wiring of Radio Equipment, Cords and Plugs
Losson 5A
properly clamped in the plug. If necessary a layer of rubber
tape should be used under the cord damp.
Testing of cords . — After assembly it is advisable to check
the cord with an ohmmeter or by some similar means to
see that the conductors connect through the proper pins
at each plug. The most satisfactory method of testing the
cord is by installing it in the proper equipment, and trying
it under actual service conditions. Quite often a cord will
develop trouble in service that does not show when tested by
other means.
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Lesson 5A
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LESSON 5A
LABORATORY
(For Radio Students Only)
Tools and materials for operations 1 to 6 inclusive.-
*1 ea. Blow torch
*1 ea. Soldering iron
1 ea. Pliers, 8-inch side-
cutting
1 ea. Pliers, long-nose
(TL-126)
1 ea. File, with handle
1 ea. File card
Items marked
*4 pcs. Wire, copper No. 10
*4 pcs. Wire W-50
*1 pc. Wire, copper No. 6
*1 ea. Large terminal lug
*2 pcs. Brass sheet (from
lesson No. 4)
*Bar solder, rosin core sol-
der, rags, seizing wire
are not placed on the memorandum receipt.
Procedure. —
Operation 1. — Check the blow torch for broken or missing
parts. Fill and light the blow torch, using the information
contained in lesson 5. Have the operation checked by the
instructor. The blow torch will not be taken to the work
bench while burning.
Operation 2. — Check the soldering iron. Make sure the
handle is serviceable. Use the tinning jig furnished. Follow
the information contained in lesson 5 and tin the iron.
Ins. check
Operation 3. — Clean and tin one end of each of the four
pieces of No. 10 copper wire. The tinned portion should be
about 3 inches long. This wire is tinned in the same manner
as the soldering iron, except that it is heated by the solder-
ing iron instead of the open flame of the blow torch. Lay
two pieces of the wire together with the tinned ends overlap-
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Wiring of Radio Equipment, Cords and Plugs Lesson 5A
•
ping. Seize the wires with a few turns of seizing wire at
each end of the tinned part. Solder this joint, using the flow
method. Prepare a joint with the other two wires. Solder
this joint, using the sweat method. Note the difference be-
tween the two joints. The best way to solder the joints in
this operation is to place a piece of scrap wood on each side
of the wire, and place it in a vise in such a manner that
the portion to be soldered is out to one side. The scrap wood
will keep the heat from running into the vise and a better
joint will be secured.
Ins. check
Operation 4 . — Solder a butt joint with the two pieces of
brass sheet. Follow the information contained in lesson 5,
and the illustration given in figure 12. Lay the pieces on a
piece of scrap wood for the soldering operation.
Figure 12
Ins. check
Operation 5 . — Use the No. 6 wire and the terminal lug
furnished. Follow the information contained in lesson 5 and
the illustration given in figure 13. Solder the wire and lug.
Operation 6 . — Use the ware W-50. Make two Western
Union splices. Solder one splice using the flow method, the
other using the sweat method.
Ins. check
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After completing operation 6, tfie student will return all
tools and material left over to the supply room. See instruc-
tor on floor of soldering classroom, before drawing equip-
ment for operations 7 to 14.
Tools and materials for operations 7 to 14 inclusive. —
1 ea. Soldering iron TL-117
1 ea. Pliers, 6-inch side-cut-
ting (TL-13)
1 ea. Pliers, long-nose (TL-
126)
1 ea. Pliers, diagonal (TL-
103)
1 ea. Knife TL-29
1 ea. Small screwdriver
1 ea. Chassis
1 ea. Plug PL-50
1 ea. Plug PL-61
*1 pc. Wire W-50
*6 pcs. Wire No. 14, enamel-
ed
*1 bundle Wire, for chassis
wiring
*3 Terminals, mounted on
block
*1 pc. Cordage CO-130
*1 pc. Cordage CO-138
•Small terminals assorted,
bus wire tinned, rosin core
solder, rubber and friction
tape, lacing cord, stranded
pushback wire.
Items marked * are not placed on the memorandum receipt.
Inspect models on display board and table , before doing
any of the operations below.
Operation 7 . — Clean and tin the electric soldering iron.
Operation 8 . — Solder a terminal, TM-10 on one end of the
lamp cord.
Solder a lug on each end of the No. 14 enameled wire. Use
information contained in lesson 5 and solder the lug accord-
ing to the illustration given under operation 5.
Solder a short piece of solid conductor pushback wire to
each terminal on the block furnished.
Ins. check
Operation 9 . — Use the information contained in lesson 5A,
solder a butt joint. This joint is made with the square bus
wire. Two satisfactory joints must be completed.
Ins. check
Complete two soldered loop joints.
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Lesson 5A
Operation 10 . — Use the No. 14 enameled wire to practice
bending loops. One satisfactory loop must be completed to
fit the machine-screw furnished.
Ins. check
Operation 11 . — This operation consists of wiring a chassis
according to figure 14 and information. The finished job
must present a neat appearance. All soldering flux must be
removed. The bus wiring shall be straight and all comers
shall be square. Soldered connection must be smooth.
Use pushback wire, connect terminals 5, 6, 7 and 8 to the
four lower terminals on the jack. These wires must follow
the same path so that they can be laced into a cable.
Using lacing twine, lace the four wires together.
Using enamel wire, connect the top terminal on the jack
to the “P” terminal on the tube socket.
Using enamel wire, connect the “G” terminal on the tube
socket to terminal No. 4 on the terminal strip.
Using enamel wire, connect the negative ( — ) terminal of
the tube socket to the center terminal of the switch.
Using the shielded wire, connect the terminals 2 and 3 of
the terminal strip to the two remaining terminals on the
switch. The shield of these two wires must be grounded.
That is, the shields are connected together by direct solder-
ing or by soldering a piece of wire to both shields and then
soldering a lug on the end of the wire. The lug is then bolted
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to the chassis with a machine-screw.
Using square bus wire, connect terminal No. 1 of the
terminal strip to the nearest ground lug.
Using square bus wire, connect the positive ( 4- ) terminal
of the tube socket to the ground lug.
Ins. check
Operation 12 . — Remove all wiring from the chassis. Clean
the terminals of all solder by heating the terminal and then
brushing the solder off with a* clean cloth. Do not file or
scrape the terminals.
Operation 13 . — Replace the parts on the chassis.
Ins. check
Operation lk - — Prepare cordage CO-138 for attaching
plug. Use the procedure outlined in the lesson sheet. Submit
the work to the instructor.
Attach the plug PL-61 to the cord submitting the work to
the instructor for checking before assembling the plug.
Prepare cordage CO-130 for attaching a plug. Do not
solder a ground lead to the shield in this case, but unbraid
the shield and twist it into two pigtails. Tin these pigtails
thoroughly. Cut the conductors and pigtails to about %-inch
in length. Remove Vs -inch of insulation from the conductors
and tin them. Solder a terminal TM-142 to each conductor
and each pigtail. Submit the work to the instructor.
Attach the plug PL-50 to the cord after taping the shanks
of the terminals to prevent their shorting. Be careful when
putting the nuts and screws in place that they are not
scarred unnecessarily. Submit the work to the instructor
for checking.
Ins. check
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Woodworking
Lesson 6
LESSON 6
WOODWORKING
1. General. — Woodworking is the art of taking rough lum-
ber as it comes from the mill and turning it into a finished
product. Woodworking is divided into a large number of
special operations, only those pertaining to the use of simple
hand tools will be covered here. Woodwork, in order to pre-
sent a pleasing appearance when finished, should be cut,
shaped, jointed and assembled with care. Even though the
completed piece is not to be painted or stained, it will hold
together better and last longer if the parts are cut square
and the joints fit tightly.
2. Holding devices. — The most common holding devices are
the work bench and the vise. A heavy, well braced work
bench is necessary regardless of the type of woodwork being
done. It is a convenient place to layout and assemble the
work, keep the tools required for the job, and store the fast-
ening devices and finishing material required. The bench
should be equipped with a vise, bench stop, drawer and shelf.
The bench stop is simply a steel plate, with teeth on two
sides, which may be raised or lowered by means of a screw
in its center. The bench stop acts as a backing for surface
planing or where pieces are too small or thin to be held in
the vise.
The vise usually consists of two jaws faced with wood and
a steel screw equipped with a handle. It is used to hold the
wood stock during the cutting and smoothing operations.
The wood faces on the steel jaws prevent the wood stock
from becoming marred. It is a very poor practice to hold a
piece of wood in a metal working vise. If this becomes neces-
sary, place a piece of scrap stock on each side of the piece
being cut or shaped.
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3. Laying out the work. —The more care exercised in mea-
suring the pieces, the less time and labor the worker will be
required to expend in squaring and finishing the parts. The
layout devices most frequently used in hand woodwork are:
the try square, steel square, marking gauge, 2-foot boxwood
rule and the 6-foot zigzag rule.
The try square consists of a steel blade, 4 to 12 inches
long set in a beam or head of wood or steel. The angle
between the inner edge of the blade and the beam is 90 de-
grees. The outer edge of the blade is graduated in fractions
of an inch, the smallest division usually being %th of an
inch. In addition to being used as a layout tool, the try
square is used to test the straightness and flatness of small
pieces of wood, and test edges and ends for squareness.
The steel square is similar in construction to the try
square, except that it is usually made in one piece and is not
so accurate. The shorter part is called the tongue, the longer
part is known as the blade. There are several graduations
found on the edges of the steel square. Usually they are Vfc,
1/4, 1/10, 1/12 and 1/32 parts of an inch. The square also
normally contains a board foot scale and a rafter table.
Marking gauge . — This tool consists of a square ruler, with
a pin set in one end, a head with a square hole in its center
and a set screw. The ruler slides in the hole in the head
permitting measurements from 1/16 of an inch to 6 inches to
be laid off along the grain.
Rules . — The 2-foot boxwood rule and th^ 6-foot rule are
used in general measurements, to estimate the number
of pieces that may be cut from a large board and when
constructing large frames or braces. These rules should not
be used where a high degree of accuracy is required.
Transferring the dimensions . — A pencil with a thin flat
point should be used to mark with the grain if the marking
gauge cannot be used. A sharp knife is best suited for mark-
ing across the grain. Knife or pencil should have the upper
end tilted away from the square or rule. This causes the
marking end to run close to the layout device, giving an
accurate measurement.
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Woodworking
Lesson 6
Cross
grain
Figure 1
4. Cutting out the ports. — All parts required should be cut
first. Do not cut them exactly to size, except where very
rough work is being done, as some waste wood is required
for smoothing and squaring. Letter or number each piece
as it is cut to eliminate duplication of parts. The saw cut
should be made outside of the line never exactly on it. Split-
ting the line will cause the piece to be too small.
Pieces are usually cut out of the lumber stock with some
type of rip or crosscut saw. The rip saw is used to cut with
the grain, the crosscut saw cuts across the grain. A cut
with the grain separates the long wood fibers, a cut across
the grain severs them. See figure 1.
Teeth of Hip Saw
Teeth of Ctosscut Saw
Figure 2
<o
tN
N
h
Saws, with a few exceptions, have their teeth alternately
bent out of line. This is called set. It makes the saw cut or
or kerf wider than the saw back and prevents binding. Saws
used on damp spongy lumber require a greater set than
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those used on dry well seasoned lumber. The principal differ-
ences between the rip and the crosscut saws are: The shape
of the teeth, the way the teeth are sharpened, and the
amount of set. See figure 2.
To make a cut with either type of saw, the following rules
should be observed.
Start the cut with the end of the saw, using a back stroke.
After the kerf is started, use a long stroke, running the
saw in line with the arm and shoulder after the cut is
started. The correct angle between the saw and the work
for ripping is 60 degrees, for cutting across the grain 45 de-
grees. If possible the work should be held in a vise or sup-
ported on a sawhorse or other frame, high enough from the
floor to prevent the end of the saw from striking. This gives
the operator the best control over the saw. A very square
and even cut can be made across the grain by placing the
beam of a square on the work, with the blade in line with the
proposed cut. The saw blade is then placed along the blade
of the square, which acts as a guide. The beam of the square
is moved toward the operator as the cut is increased. See
figure 3.
Figure 3
Selecting the saw . — Saws have a number stamped on the
blade near the handle which indicates the number of points
per inch. The larger this number, the finer the saw. Rip saws
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Lesson 6
usually run from 5 to 9 points, crosscut saws from 5 to 11
points. The back saw, a crosscut saw used for finer cuts, has
from 12 to 16 points per inch.
The 5 V 2 -point rip saw, 26 inches long is best for general
work. A finer saw should be used for thin material. The 10-
point crosscut saw, 26 inches long, is the most popular and
and is very efficient for general work. Lumber 2x4 inches
and heavier should be cut across the grain with a 7 or 8
point saw. Crosscutting thin wood, cutting mitres and other
types of wood joints should be done with the back saw. This
leaves an end surface which requires very little dressing.
Inside, circular and irregular cuts . — These cuts are made
with the compass, keyhole and coping saws. The compass
and keyhole saws have narrow, tapered blades and are used
to cut out circles, braces, round corners, for circular and ir-
regular openings, etc. The coping saw is used mainly for
scroll and fret work.
5. Planing. — This operation brings the piece to exact size,
squares it, smoothes the edges and surfaces. The plane is
nothing more than a beveled cutter set in a block of wood or
steel, so that the operator can use both hands and rapidly
smooth, true and bring the stock to size. The plane is equip-
ped with an adjusting lever which is used to square the cut-
ter with the sole or bottom of the plane, and an adjusting
nut which regulates the depth of the cut. A common mistake
is to set the blade too far out. Take off thin shavings, not
thicker on one edge than the other, and the best results will
be obtained without gouging the work or clogging the plane
with shavings.
Outside of having the plane cutter sharp (See lesson 1)
and holding the tool as square as possible, there is very
little to think about while planing. The start of a stroke
is made with more pressure on the knob with the left hand
than is exerted by the right. The pressure should be even in
the middle of the stroke. At the end of the stroke apply pres-
sure to the handle with the right hand and practically none
with the left hand. The steps to follow when truing up stock
are: Plane work face flat and smooth; plane work edge
straight, square and smooth; measure and plane to width;
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plane piece to thickness required; mark for square end on sill
four surfaces, saw and plane end, allowing a little waste
stock for planing; (plane from edges to center) ; measure to
length, cut and square second end.
Planes . — The two general types of planes are the bench
and block. The block plane is used across the grain. The
bevel of the cutter is turned up and the cutter is set in the
plane at a low angle for ease of operation. Block planes run
from about 4 to 6 V 2 inches long. The bench plane is used
with the grain. The bevel of the cutter is down and the edge
is backed by a cap iron, which acts as a deflector for the
shavings. The four most commonly used bench planes are:
Smooth. — 51/2 to 10 inches long. This plane is very useful
in getting down into the hollows of a piece of wood.
Jack . — 14 inches long. This is the best plane for general
work.
Fore . — 18 inches long. This plane is used for planing long
pieces.
Jointer. — 20-24 inches long. This plane is used to smooth
exceptionally long pieces and even up pieces for glue joints.
6. Wood chisels. — The wood chisel is a hand guided, sharp
edged cutting tool. One end is ground to a bevel from 20 to
30 degrees, the other end is equipped with a handle. This tool
is made in a large variety of shapes for cutting joints,
grooves, slots, fluting, wood turning, wood carving, box core
work, etc. The four types of wood chisels most commonly
used are:
Butt . — A short thin chisel, used like a pocket knife in con-
fined places, such as seating a hinge or door lock.
Paring . — A long thin blade, used like a plane to remove a
thin shaving from a piece that does not fit well.
Firmer . — A medium thick chisel for general work.
Framing . — A thick heavy chisel, for use on heavy timbers
or other places where a severe strain is placed on the tool.
The butt and paring chisels are worked by hand only, the
firmer and framing chisels may be driven by a wooden
mallet.
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7. Mallets. — The wood mallet is a very heavy wooden ham-
mer provided with a large cylindrical shaped head. It is used
for driving wood chisels, wooden pins, etc. Mallets are some-
times made of leather, lead or brass.
8. Rasps. — The wood rasp is a tool similar to a file, except
that each tooth is punched from the body of the tool. It is
used for rough cutting and shaping of wood and soft metals.
The rasp is used with pressure on the forward stroke only.
This tool cuts very rapidly but leaves the surface very rough.
9. Wood bits. — The wood bit is a tool used for boring holes
of various sizes in all types of wood. Usually it has a feed
screw to draw the bit into the wood, a spur to score the
outer edge of the hole to prevent splintering, and cutting
lips that cut the chip out after it has been scored. The bit
usually has a square taper on the end of the shank. There
are three common types of wood bits.
Single twist . — This bit has a single spiral and one spur
only. It is used in rough construction work. The ships auger
is also a single twist bit which is used to bore holes in heavy
timber. It has no spur but the cutting lip is continued ver-
tically, which causes a heavy chip to be cut out.
Double twist . — This bit has a double spired and two spurs
and cutting lips. It cuts a smoother hole than the single
twist bit. It is used for general work, also in plain cabinet
and sash work.
Straight core . — This bit has a spiral milled around a
straight center core, two spurs and two cutting lips. It bores
a much smoother hole than the single or double twist bits,
and is used in all types of cabinet and furniture construction.
In boring holes, do not run the bit completely through the
wood from one side. When the point of the feed screw comes
through, reverse the piece and finish the hole from the other
side. This prevents splintering the surface of the wood
around the hole. Wood bits are usually graduated in six-
teenths. The smallest is a No. 3 or 3/16 inch, the largest,
No. 16 or 1 inch. The number stamped on the shank of the
bit indicates the diameter in sixteenths of the bit. Example:
A number 7 bit will bore a hole 7/16 inches in diameter.
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See display board for examples of wood bits.
10. Ratchet brace. Angle brace. — The brace is a tool used to
hold, rotate and apply pressure to wood bits. It is a metal
crank with a handle on one end and a chuck on the other.
The chuck has two jaws to hold the square taper end of the
wood bit. This chuck should never be tightened with a
wrench, but by hand only. There is a ratchet located just
above the chuck which permits the bit to be rotated continu-
ously when a full sweep of the handle cannot be obtained.
This feature is very helpful when boring holes in corners and
attics.
The angle brace is equipped with a double sweep, connect-
ed together by means of a universal joint. This makes it
more efficient in close quarters than the ratchet brace be-
cause the user can always make a full sweep with the inner
handle.
11. Draw knife. — The draw knife is a large, sharp edged
blade having at each end a handle at right angles to the
blade. The blade is beveled on one side only. The draw knife
is used to trim telephone poles, the quick shaping of rough
parts and other dressing to shape where appearance is not
critical. The draw knife is pulled toward the user when
making the cut.
12. Claw hammer. — The claw hammer is composed of a
metal head fastened onto a wooden handle. One end of the
head has a flat or slightly rounded face for driving nails, the
other is shaped into a claw for removing nails.
13. The level. — The level is used for guiding and testing.
It is a bar of wood or steel, equipped with two glass tubes,
both filled with alcohol and a bubble of hydrogen. One tube
is located in the side of the frame, the other in the end. The
level can be used to test either horizontal or vertical surfaces
for levelness.
14. The screwdriver. — The use of this tool was described in
lesson 1.
15. Wood joints. — There are a large variety of joints used
to fasten wood parts together, from the butt joint, which is
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Lesson 6
simply placing the two pieces together at an angle and nail-
ing or screwing them in place, to the blind dovetail which is
used in the finest furniture construction. A few of the more
common joints are illustrated in figure 4. Regardless of the
type of joint used, the measurements must be accurate and
the members cut square to insure a snug fit. A loose joint
will weaken the entire structure.
Figure 4
16. Fastening devices. — The most common devices used to
hold woodwork together are: nails, screws, bolts, glue, dow-
els, straps, corrugated nails, spikes, etc. A few general rules
to be followed when fastening wooden parts together are
given below.
Metal such as hinges and locks, requires a wood screw.
Do not use a screw or nail large enough to cause the work
to split.
If the nails go through the wood, they should be bent over
and clinched.
Never use wood screws that go completely through the
wood, as this reduces the holding power of the screw.
Where bolts are used through the wood, a washer should
be used both under the head and the nut.
Nails . — The wire nail is the one most commonly used.
Nails run in size from 2d (one inch) to 60d (6 inches). For
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certain classes of work nails are made of copper or brass.
Wire nails also may have a blue cement or galvanized finish
to prevent rust. For general work, the common nail is used.
This is the one with the wide head. Cabinet work requires
the use of a finishing nail. This nail has a very small head.
Rules have been formulated regarding the length of nails to
be used for any given work, they are listed below.
General work in medium hard timber requires a nail, the
penny length of which shall not exceed the thickness of the
Jx>ard in eighths of an inch. For example, % inch lumber
requires a six penny nail.
In soft wood, the nail may be one penny larger.
In hard wood, the nail should be one penny smaller.
The term penny, written as 2d, 4d, originally indicated
that one thousand of these nails weighed the number of
pounds indicated by the figure.
Wood screws . — Wood screws are usually made of brass,
iron or steel. They are used to hold woodwork together
where a neat appearance is required or greater holding pow-
er than that afforded by nails is needed. A wood screw does
not injure the material as much as a nail, also they are
easier to remove. If a screw is hard to drive, a small pilot
hole may be bored or else the threads of the screw may be
covered with soap before driving. Two other types of wood
screws are: lag and drive screws. These screws have square
or hex heads and are driven with a hammer or turned with
a wrench. Wood screws sometimes rust or become stuck in
the wood. The following methods may be used to ease their
extraction. They may be tapped on the head with a hammer
or the head heated with a hot soldering iron. If in a piece
where appearance is not important, oil may be applied
around the head and allowed to soak in. The student is refer-
red to lesson 3 for the method used in measuring wood
screws.
17. Wood finishing. — The plane usually leaves some small
ridges or rough places on the surfaces of piece of wood.
Before the work can be painted or stained, these must be
removed. There are a great many elaborate methods used to
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prepare wood for finishing, only the simplest is described
here.
Wood scraper . — This tool is a thin piece of sheet steel,
with the sides filed flat and a portiop of the filed surface
turned over to form a burr. It is used where the grain is not
even and the plane has gouged out portions of the wood. The
scraper must always be used with the grain, running it
across the grain makes the surface rougher instead of
smoothing it. The scraper should be pushed away from the
operator as this gives the best control over the tool.
Sandpaper and garnet paper . — The scraper will not leave
a surface very smooth as it cuts at a fairly rapid rate, and
leaves some of the wood fibers turned up in the form of fuzz
on the surface. An abrasive paper is used to cut this fuzz
from the wood. “Sandpaper” consists of small particles of
flint glued to a paper backing. Garnet paper is made in the
same way except that the abrasive material cuts much bet-
ter than flint and lasts longer.
Sandpaper is graded from 3/0 to number three, those
grades in the zero series are considered fine, while those in
the whole number series are considered coarse. Garnet paper
is graded in the same way, except that the finest grade
is 7/0.
A fairly coarse grade is used first and then the piece is
finished with a fine grade. Always sand with the grain, sand-
ing across the grain, scores the wood and this will show thru
a stained finish.
Sandpaper is also used to finish or polish some of the
softer metals.
Review questions. —
1. Name the two common holding devices required for
woodwork.
2. Name the two parts of the try square.
3. Name the two parts of the steel square.
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4. What two tools are used to lay off dimensions across
the grain?
5. Name two tools used to cut out wooden parts.
6. Name the two general classes of planes.
7. What is the rasp used for?
8. A wood bit has the No. 6 on the shank. How large a
hole will it bore?
9. Name two types of braces used to hold wood bits.
10. Name two types of common wood joints.
11. Name three fastening devices.
12. Which has the greater holding power, nails or screws.
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Woodworking
Lesson 6
LESSON 6
LABORATORY
Tools and materials. —
Tools and materials that are required to perform the job
assigned to you by the instructor.
Procedure. —
Report to the instructor for an assignment to a job. When
all work is completed, submit to the instructor for approval.
The student should be able to identify any tool described
in the lesson sheet. Those with which he is not familiar
may be drawn from the supply room and taken to the in-
structor for explanation.
Ins. check
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Lesson 7
Shop Work
LESSON 7
MISCELLANEOUS TOOLS
1. Splicing clamps, 10 Inch (LC-24). — The splicing damp is
a tool used to make Western Union and sleeve splices in the
larger sizes of wires. In lesson 2, the student learned to
splice wires with the fingers, aided by small pliers. This
method is not satisfactory for copper and phosphor bronze
wires from 12 to 6 gauge and galvanized iron wires from 12
to 9 gauge.
y- Running end
=EEEE=E3E
Standing wire
y —
TL-)2»I
Figure 1
The Western Union splice is not satisfactory for joining
wires of the sizes indicated in the paragraph above. It does
not give as good an electrical contact as a sleeve splice and
should be used only in an emergency, where there are no
sleeves available. In addition, hard drawn copper wire nicks
easily because it is very brittle. A nick in the Western Union
splice, made while forming the neck or buttons will cause
the wire to break very quickly. The steps required to form
the Western Union splice with the aid of splidng clamps are
illustrated in figures 1, 2, and 3.
Clean copper wire with No. 0 emery doth and wipe gal-
vanized iron wire with a cloth before splicing.
Overlap the ends of the wires about 12 inches.
Turn the clamps so that the single holes are on the inside of
the handles, select the hole that fits the wire being spliced,
place the clamps on the wires as indicated in figure 2 and
fasten the handles.
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Miscellaneous Tools
Lesson 7
Rotate the right hand clamps one and one-half turns in
one direction and the left hand clamp one and one-half turns
in the other direction. This should form the neck, which is
required to have six half turns or three full turns. As soon
as the turns in the neck have been checked, remove both
clamps. Place one clamp over the last turn of the neck but
do not fasten the handles. This will damage the wire and
weaken the splice.
Bend running end , , Position ° f $%!!!&
to stort button — at start of buttons 1 f at finish of neck.
(a)
(b)
\\
. Button^ . Neck . i
Stums) jturn ■ (3 turns)
TL-3283
Figure 3
Use the 8-inch pliers and place the five close turns, which
form the button, around the standing wire and cut off the
excess portion of the running wire as short as possible. Move
h . (is .
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the splicing damp to the other end of the splice and form the
other button. The turns in the buttons should be as close to-
gether as possible and tightly wrapped about the standing
wire.
Splicing sleeves are made of copper, for copper and phos-
phor bronze wire, and tinned steel for joining galvanized
iron wire. Clean all dirt from the tubes of the sleeve before
inserting the wire. The steps required to make a sleeve splice
are illustrated in figure 4. Turn the splicing clamps so that
the double holes are on the inside of the handles.
Rotate the clamps as described for Western Union splices.
When six half turns have been placed in the sleeve, bend the
ends of the wire back over the sleeve and cut off as illustra-
ted in figure 4.
f from end
of sleeve
Place c/amps here.
l using a double hole
About 2' to keep
wire frgm slipping
TL-)Z*4
2. Electrician’s scissors. — These scissors are a short heavy
bladed tool used to cut soft copper wires not larger than 18
gauge and to remove paper insulation from small wires. The
back of the blades are corrugated to aid in the removing of
insulation and cleaning the wire. The electrician’s scissors
find their greatest use in splicing cables. These cables have
a great many pairs of paper covered wires in them, and if
pliers were used to remove insulation it would require a
great deal of extra labor in picking them up each time the
insulation was removed from a wire, laying them down
again to twist the joint and so on. The scissors can be held in
the hand, with one finger through one of the loops in the
handles and are always ready for use. The method of holding
and cutting with the scissors is illustrated in figure 5.
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Miscellaneous Tools
Lesson 7
3. Wrenches. — The wrench is a tool used for gripping and
turning bolt-heads, nuts and pipes. Wrenches are divided in-
to three general classes: plain or fixed, adjustable and
socket
Figure 5
Plain or fixed wrenches . — This type of wrench is made to
fit only one or two sizes of bolts or nuts, depending on wheth-
er it is single or double ended. Some examples of fixed
wrenches are illustrated in figure 6.
Adjustable wrenches . — Since the average mechanic can-
not have a complete assortment of fixed wrenches, a type
of wrench with one fixed and one movable ja\y is made.
There are three general types of adjustable wrenches: mon-
key, crescent and Stillson. The monkey and crescent wren-
ches are used for nuts and bolt-heads. The Stillson wrench
is used for pipes only because the toothed jaws will damage
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Figure 6
bolt-heads or nuts. The three types of adjustable wrenches
are illustrated in figure 7.
Figure 7
Socket wrenches . — This type of wrench is usually stronger
and more useful than the fixed or adjustable wrenches be-
cause they grip all sides of the nut or bolt-head at the same
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Miscellaneous Tools
Lesson 7
Single Hexagon Double Cornered
docket Hexogon Socket
time, which is less likely to cause damage than are the
other types of wrenches. The socket wrench is also more
efficient for work in dose places and for speed of operation.
In using the socket wrench it is well to remember that it is
possible to apply more force to it than the work can stand.
If the user of a socket wrench will bear this fact in mind, he
will probably never be faced with the tedious job of remov-
ing a screw or bolt with a battered head or sheared off end.
Types of socket wrenches are illustrated in figure 8.
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Lesson 7
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LESSON 7
LABORATORY
Tools and materials. —
2 ea. Splicing clamps (LC-24)
1 ea. Pliers, 8-inch side-cutting
1 ea. Scissors, electrician’s
*4 pcs. No. 10 copper wire
*4 pcs. No. 12 galvanized iron wire
•Sleeves, copper No. 10
•Sleeves, tinned steel No. 12
•Emery cloth
Items marked * are not placed on the memorandum receipt.
Operation 1 . — Make a Western Union splice, use the No.
10 copper wire.
Make a Western Union splice, use No. 12 galvanized iron
wire.
Ins. check
Operation 2 . — Make a sleeve splice, use the No. 10 copper
wire.
Make a sleeve splice, use the No. 12 galvanized iron wire.
Ins. check
Operation 8 . — Practice cutting wires with the electrician’s
scissors. If the student experiences any difficulty with this
operation, the instructor will demonstrate the proper method
of using the scissors.
Ins. check
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Lesson 8
LESSON 8
ROPE, SPLICES, KNOTS AND BLOCKS
1. General information on rope. —
a. Terms used in the manufacture of rope . —
Fibres. — Materials from which yarns are spun.
Strand. — Yarns twisted together.
Rope. — Strands twisted together.
Laying. — The process of twisting strands together in
making rope.
b. Terms used in the handling of rope . —
Bight. — A section of the rope turned back on itself.
Turn or loop. — A turn on a rope with the ends extending
in opposite directions.
Round turn or bend. — Any turn in a rope around itself
or some other object.
Knot — A combination of bights and turns arranged so
the tight part of the rope will bear on the free end of the
rope.
Hitch. — Attaching a rope to an object so it may be
readily detached.
Half-hitch. — A turn of the rope arranged so a section of
the turn will bear on another section of the turn.
Haul. — Pull on a rope.
Running part or fall line. — The free end or that part of
the rope that is hauled upon.
Standing part. — The stationary end or that part of the
rope that is tight.
Seized. — Twoparallel ropes bound together.
Served (whipped) . — The end of a rope wrapped to keep
the strands from untwisting.
Splice. — Two ropes joined together by interweaving the
strands.
Taut. — Hauled tight or under tension.
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c. Standard mania rope . — Manila rope is furnished in the
following sizes and each size may be obtained in coils up to
1200 feet in length.
TABLE 1
Size,
( Diameter
in inches)
Breaking
strength , new
rope (lbs.)
Safe working
strength, new
rope (lbs.)
Weight of
rope,
(lbs. per ft.)
%
700
200
.02
%
1450
400
.0417
%
2450
700
.075
%
4000
1100
.133
%
4900
1400
.165
1
8200
2300
.27
1%
12500
3000
.42
1%
17500
5000
.6
Half the value of the loads specified in this table shall be
used if the rope has been in service more than 6 months.
New rope loses one-third to one-half of its strength in 6
months of ordinary use. Spliced rope has approximately
80 percent of its orginal strength. Rope is usually sold by the
pound. When ordering rope, where this method is used, con-
vert the footage into pounds by multiplying the required
number of feet by the number of pounds per foot as given in
table 1.
Example: Required 1500 feet of y 2 -inch. 1500 times .075
equals 112.5 lbs.
d. Uses of manila rope . — In telephone work the rope used
will depend on the load and other conditions encountered.
Manila rope, preferably dry, should be used where there is
a possibility of contact with wires carrying current. If the
rope is wet or damp the workmen should wear rubber gloves.
If manila rope other than the standard rope is used, examine
it carefully, to make sure it does not contain a metallic
strand. To do this untwist the strands for a few inches, then
untwist the yarns.
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e. Selecting the size of rope for the work to be per-
formed . — The approximate weight of the load to be handled
must be known, before selection of the proper size rope.
After determining the load, and the rigging that is to be
used, select a size of rope, whose working strength will not
be exceeded by the weight of the load to be applied. If neces-
sary to use blocks, select the simplest rigging to accomplish
the work with safety and without loss of time. The size of
rope required for use with blocks is determined by the
diameter of the sheave groove. A sheave groove with too
small a diameter places an excessive bend in the rope, caus-
ing the fibres to break. Table 3 shows the proper size ropes
for the various size blocks. (See rigging.)
/. Storing rope when not in use. — New rope shall be left
in the original coil until required and shall be stored in a
dry place, in a manner to provide a circulation of air. Used
rope shall be stored in the same manner, after it has been
coiled or placed on reels. Do not store new or used rope un-
less it is completly dry. To dry rope hang it up in loose coils
on harness hooks or rounded pegs, to permit a free circu-
lation of air around and through the coils. Rope should be
dried as soon as practical after it is wet. The drying should
be done by placing the rope in the sunshine or in a warm
room. Rope, wet or dry, should never be placed over a hot
radiator or placed too near a fire.
g. Transporting rope . — When transporting rope in trucks,
it shall be hung on brackets provided for this purpose; the
floor being kept dear to prevent tripping men, cutting the
rope with edged tools, and tangling of rope. Never store or
transport rope near a storage battery, as the acid or alkali
will seriously injure the rope.
h. Inspection routine. — The man in charge of a construc-
tion crew should inspect tackle for faults when it is issued,
and at legist once, during each week of use. He shall make an
inspection of the surface of the rope and blocks for any
faults that may have developed. Inspection shall be made
once each month for the internal condition of the rope.
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The person responsible for the tackle shall at all times
assume the responsibility of determining that the ropes and
blocks are in good condition, and that their appearance in-
dicates neither deterioration nor injury, sufficient to affect
their strength.
i. Inspection of manila rope . — In view of the numerous
conditions that may affect the strength and, that only part
of the rope may be affected, examination should be made to
determine the condition of the rope through its entire length,
as explained below. If there is any doubt of the safeness of
the rope, it shall be exchanged for rope in good condition.
The important things to look for on the surface of the rope
are as follows :
(1) Abrasions or broken fibres. — Caused by dragging
rope over sharp stones, by kinks or crosses in the rope
when under tension, cutting with a sharp tool or by exposure
to acids such as the acid used in storage batteries.
(2) Extremely soft. — Caused by overstressing rope, wear-
ing out due to normal life of the rope, or by exposure to
any cause that will injure the inner fibres.
When inspecting rope for internal faults, the strands
should be separated at 3-foot intervals and the fibres
inspected for the following:
(1) Broken fibres. — Caused by working rope through
sheaves which are too small, or tying to an object which is
too small.
(2) Mildew, mould or fine powder. — Caused by rope not
being dried nor cleaned properly after being subjected to
mud or sand. The fibres of a rope will change color if it is not
properly dried before being stored. Fine powder in rope
indicates the presence of grit. To remove grit, the rope
should be whipped up and down on a hard surfaced road,
after being thoroughly dried.
j. Inspection of blocks . — Blocks should be inspected to
determine their condition as suggested below:
(1) Bent, broken or cracked shell.
(2) Cracked or broken sheave.
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(3) Cracked or broken becket
(4) Cracked or broken straps.
(5) Bent hook.
(6) Cotter pin missing.
(7) Roller bushing not functioning.
If any of the above conditions exist and there is any doubt
as to the safety of the block, it shall be exchanged for one in
good condition.
k. Maintaining blocks in the field . — Keep blocks free of
oil and dirt The sheaves of the standard blocks sire roller
bushed, and operate better without oil which tends to collect
oil and grit, thereby causing the rollers to bind. If the
sheaves do not function properly, remove the sheave as
outlined below and remove the dirt by tapping the sides of
the sheave lightly.
If the hook of a block has started to open, exchange the
block, or if a spare hook is available replace the hook. This
is done by removing the cotter pin from the sheave pin with
pliers. It may sometimes be necessary to oil the pin with
kerosene and drive it out with a hammer. After removing
the cotter pin, pull out the sheave pin, being very careful
not to drop the'sheave which will break or scar the edges of
the sheave. Pull hook straps out and replace the new hook in
position.
l. Coiling and uncoiling rope . — When used rope is not
placed on reels, lay out a turn of the desired size and con-
tinue the turns in a clockwise direction.
In uncoiling used rope, turn the coil over and draw the
end first laid down, from the inverted coil. Be careful not to
select the wrong end, if the coil has been tangled or upset
Remove new rope from coil as explained below; this
method retains the rope in its proper form and prevents
kinks. See figure 1.
(1) Remove the binding material and secure outside end
of rope to an adjacent coil.
(2) Lay the coil on the flat side with the inside end near-
est the floor.
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(3) Reach down through the coil, grasp the free end of
rope and draw out through the top of coil.
Figure 1
m. Cutting manila rope . — Before cutting rope, wrap sev-
eral turns of friction tape around the rope on each side of
cut, and cut rope with a sharp tool. If it is desired to keep
the ends from permanently untwisting, serve or whip them
with a strong twine or place a crown splice in the ends.
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2. The more common rope splices. — a. Serving splice ( whip-
ping ). — The operations required to serve the ends of a rope
are as follows. See figure 2(a).
(1) Unlay one strand of the rope back a little more than
one turn, to a point where the serving is to begin. Under
this strand lay the twine, leaving the end marked 1, 8 to 10
inches long as shown in 2- A. Then relay the strand into the
rope, keeping it tightly twisted and held firmly in place.
(2) Let the short end of the twine 1, hang down the rope.
Wind the long end of the rope marked 2, around the rope,
just above the short end as shown in 2-B.
(3) Lay the end of twine 1, along the rope towards its end
and there bend it back, thus forming the open bight 3, as
shown in 2 -C, which can be pulled in under the serving when
tucking the ends.
(4) Cay the sides of the bight 3, in a groove of the rope.
Wind the long end of the twine 2, around the rope and the
doubled twine, being careful to pull it up tightly and to leave
no open spaces between the turns as shown in 2-D.
(5) Continue winding as far as desired, then pass the
long end 2 of the twine through the bight 3, as shown in 2-E,
and pull the long end up firmly. By pulling on the free end 1,
of the bight 3, draw the long end of the twine 2, downward
underneath the serving, to about the center, not all the way
through.
(6) Finish the serving by cutting off the two protruding
ends of the twine as closely as possible. Cut off excess rope
as shown in 2-F.
b. Crown splice . — See figure 2(b).
(1) Unlay the rope for 10 to 12 inches and hold it in one
hand with the loose ends up as shown in 2 -A.
(2) Take strand 1 on the left and lay it across the end of
the rope between the other two strands as shown in 2-B.
(3) Take strand 2 back and down over strand 1 as shown
in 2-C.
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Figure 2
(4) Take strand 3 across 2 through bight in 1 as shown in
2 -D.
(5) Pull all ends tight as shown in 2-E.
(6) Continue tucking each successive strand over the
nearest strand and under the next strand of the main rope
as shown in 2-F.
(7) Tuck until about four complete operations are made.
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(8) Roll between two surfaces under pressure, as between
foot and floor, to smooth out splice, then cut off surplus ends
flush with the outside strands. The completed splice is shown
in 2 -H.
c. Eye splice . — The eye splice is used to form a permanent
loop or eye, in the end of the rope. This splice has 90 percent
of the strength of a straight rope. When heavy wear will
take place on the inside of the eye, it is advisable to splice
an oval thimble in the eye. An eye splice is illustrated in
figure 3(a).
(1) Untwist the strands of the rope for a length of 10 to
16 inches. Throw a bight into the rope of a size to correspond
with the size of the eye required. Select as strand 1 the
strand that is on top of the rope and between the other two
loose strands as shown in 3- A.
(2) Raise a strand on the top of the main rope and tuck
1 under it at right angles, as in 3-B, pulling it down securely.
Raise the adjoining strand in the main rope and tuck 2 under
it as in 3-B. Raise the remaining strand in the main rope and
tuck 3 through.
(3) When all the ends have been tucked through for the
first time, pull them down tight as in 3-C. Proceed to inter-
weave the strands as in a short splice.
(4) Roll the splice between two flat surfaces under pres-
sure, as between foot and floor, and trim off surplus ends
flush with the outside strands. The completed splice is shown
in 3-B.
d. Short straight splice . — Short straight splice is used to
unite the ends of rope by interweaving strands, and when
properly made it has 80 percent of the strength of the rope.
See figure 3(b).
(1) Untwist the strands at one end of each rope for a
length of 10 to 16 inches. Butt the ends of the rope tightly
together as in 3-A laying the strands of each rope alternately
between the strands of the other rope; that is, strand 1, is
between 2 and 4; strand 3, is between 4 and 6, and strand 5,
is between 2 and 6. This process is called locking the strand.
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1 and 2, of 3 -B. Complete tying, 3 to 4, and 5 to 6, in a
similar manner.
(3) Pull all knots down tight as in 3-C.
(4) Carry each end over the adjacent strand of the rope
and tuck it under the next strand. Start with and proceed to
strand 6, in progressive order. This will produce an arrange-
ment as in 3-D. Repeat this operation until the total length
of the interweaving strands extends through a distance of
4 inches, for one-quarter inch rope, and add an additional
tuck for each next largest standard size rope.
(5) Roll splice between two flat surfaces under pressure,
as between foot and floor, and trim off the surplus ends
flush with the outside strands. The completed splice is shown
in 3 -E.
e. Long straight splice . — The long straight splice is used
to unite the ends of rope required for passing over sheaves,
by interweaving strands, and when properly made it has 90
percent of the strength of the rope and therefore it is strong-
er than the short straight splice. Figures 4 and 5 illustrate,
in sequence, the steps in making the long straight splice.
The advantages of this splice are; stronger than the short
straight splice, and smaller than the short straight splice,
thereby allowing it to pass through the sheaves of a block.
(1) Unlay only one strand of each rope for 10 or 12 turns.
Lock and draw ends of the rope tightly together, having the
single strands 1 and 2 side by side, as illustrated in figure 4.
(2) Taking care not to let the ends of the ropes separate,
unlay strand 1 from its rope one turn, and follow it with
strand 2. Keep 2 twisted up tightly and pulled down firmly
into its place. Continue this procedure until only 6 to 9
inches of strand 2 is left out, depending on the size of the
rope.
(3) Untwist the two pairs of strands left at the center and
lock them as shown in figure 4. Strand 3 between strands 4
and 6, and strand 6 between strands 3 and 5. Unlay toward
the left, strand 4 and follow it with strand 3, as was done
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toward the right with strands 1 and 2. Note. — Do not unlay
strand 6 instead of 4 and follow it with 8.
(4) Continue until strand 3 is only 6 to 9 inches long. The
breaks in the strand are now separated as shown in figure 4.
(5) Each pair of strands is tied together now, and the end
of each strand tucked. Cut all strands the length of the
shortest, that is, 6 to 9 inches long. Arrange each pair so
that the strand from the left is in front of the strand from
the right; or, in other words, arrange the strands so that
they cannot untwist from the rope without first uncrossing.
Tie each pair of strands together with an overhand knot
and pull down tightly into rope as shown in figure 5.
(6) Tuck each strand as shown in figure 5.
(7) Tuck each strand twice more, tapering the ends if
desired, and cut the end y 2 inch long.
(8) With a round stick pound down each part of the splice
and roll it between two flat surfaces under pressure, as
between foot and floor. The completed splice is shown in
figure 5.
3. The more common knots, bends and hitches used in teleplone
work. — The strength of manila rope containing a knot is re-
duced about 60 percent, as the bend in the rope places most
of the strain on the outside fibres.
a. Figure eight knot . — This knot is used to prevent the
end of a fall line from running through the blocks. See figure
6(a). Throw a turn into the rope leaving sufficient end to
complete the knot, then pass the end around the rope and
through the bight. Draw all parts down tight.
h. Block becket bend . — This knot is used when attaching a
rope to the eye of a guy rod or to the becket of a block,
where a temporary connection is desired. See figure 6(b).
(1) Pass the rope around the thimble on the becket of a
block as shown in 6-- A.
(2) Take a turn around the standing part outside of the
bight as illustrated in 6-3.
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(3) Take a second turn around the standing part through
the bight, forming two half-hitches in reverse as shown in
6-C.
Figure 6
c. Square knot . — This knot is used in uniting the ends of
the same size ropes, that may be placed under strain. A
square knot, joining two ropes of unequal size is very apt to
slip. Figure 7 illustrates a square knot.
(1) Cross the ends of the rope, placing the right under the
left as in figure 7 -A.
(2) Bend each rope back on itself as shown in 7-B.
(3) Wrap end marked 1, around the end marked 2, away
from you as shown in 7 -C.
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(4) Pull all parts down tight. The completed knot is
shown in 7 -D.
■Ends separated by bighr ^ TL‘3322
Figure 7
A granny knot is shown in figure 7, so that it may be
readily identified and avoided.
d. Bowline knots , general . — The bowline knots are used in
making hitches of all types and are formed in various ways,
depending upon the conditions encountered. It is a tie of uni-
versal use, and is the best known method for forming a bight
that will not slip under tension and is easily untied.
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Figure 8
e. Single bowline at the end of a rope, not attached to an
object . — This knot is used for attaching a rope to the hook of
a block or joining the ends of ropes of different sizes. See
figure 8.
(1) Grasp the standing part of the rope with the left
hand, at a point where the turn T is desired. This position
is determined from the size of the bight Y, required. Hold
the free end in the right hand.
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(2) Move the right hand forward and lay the free
end across the standing part of the rope, above the left hand,
with sufficient end to complete the subsequent turns. Hold
the right hand stationary and bring the left hand upward
and forward as indicated by the arrow 1.
(3) Just as the left hand is passing the right, turn the
right hand palm up, which will result in the formation of a
loop in the standing part of the rope, with the end of the
rope projecting up through it.
(4) Grasp the free end with the right hand and move it
forward.
(5) Pass the free end around and behind the standing
part of the rope from right to left, as indicated by the arrow
2, then pass the free end forward and down into the turn
again, from above, as indicated by the arrow 3.
(6) Draw all parts down tight The completed knot is
shown in figure 8 -F.
Figure 9
/. Single intermediate bowline . — This knot is used to
attach the rope to the hook of a block, where the end of the
rope is not readily available. See figure 9.
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(1) The operations required in making this knot are
identical with the single bowline, not attached to an object,
with one exception; that is, in step (D) the part with which
the knot is completed is not a free end but a part of the rope
doubled back in a bight.
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g. Single bowline, at the end of a rope, attached to an
object. — This knot is for tying a bowline through a ring or
eye. See figure 10.
(1) Throw a turn into the rope, leaving sufficient end to
complete the knot, then pass the free end through the eye or
around the object, holding the standing part with the turn in
the left hand as shown in 10-A.
(2) Pass the free end through the turn in the standing
part of the rope as illustrated in 10-B.
(3) Bring the free end from right to left, over the stand-
ing part of the rope and turn it under, passing the end
through the turn as shown in 10-0.
(4) Draw all parts down tight. The completed knot is
shown in figure 10-D.
h. Double bowline. — This knot is used in tying at inter-
mediate points, and allows two ropes to pass through the eye
or point of strain, thereby doubling the strength at the point
of greatest stress. See figure 11.
(1) The operations required to make this knot are identi-
cal with the operations of the single bowline, at the end of a
rope, attached to an object.
t. Double bowline on a bight. — This knot is used as a semi-
permanent eye in the middle or end of a rope, to engage a
hook, clevis or some other similar fastening. This knot
allows two ropes to pass through the fastening. See figure
12 .
(1) Double the rope and throw a turn into it leaving
sufficient end to complete the knot as shown in 12- A.
(2) Pass the end through the turn, as explained for a
single type bowline, until the position shown at Z, is reached
as shown in 12-B.
(3) Turn the bight S, down over the front and then up in
back of turn Y as shown in 12-0.
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Figure 11
(4) Pull all parts down tight. The completed knot is
shown in 12- D.
j. Clove hitch . — The clove hitch is used in attaching tools
and materials to a hand line. It may also be used in guying
gin poles, when the tension is equally divided along the guy
ropes in opposite directions. This hitch will stand a stress in
either direction when properly set. It is quickly made and
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Figure 12
easily undone. The clove hitch is compossed of two half-
hitches made either at the end of a rope or in the middle
without access to the ends. It can be made in a number of
ways, three of which are explained and illustrated in figure
13, 14 and 15.
Method of making a clove hitch to pass over low objects,
such as a stub pole or stakes. See figure 13.
(1) Hold the rope as shown in 13- A.
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(4) Bring the loops together as shown in 13-D, then place
over the object and pull taut.
Method of making a dove hitch when there is,a pull on the
rope. See figure 14.
(1) Hold the strain on the rope with the left hand and
twist the rope to the right, with the right hand, to form a
loop in the rope, and then roll the loop over the top of the
post. Shown in 14- A.
(2) Move the left hand up beyond the loop, hold the rope
there and with the right hand form a second loop, roll it in
place and pull taut.
(3) The completed knot, in place, is shown in 14-C.
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Figure 15
The quickest method of making a dove hitch is shown in
figure 15.
(1) Cross the arms in front of the body, with the left arm
outside the right and pick up the rope as shown in 15-A.
(2) Without twisting the wrists, uncross the arms. Shown
in 15-B.
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(3) Now rotate both hands to the right, as indicated by
the arrows around the wrists, shown ip 15-B, and put the
knuckles of the left hand into the palm of the right hand.
(4) Slip the loop from the left hand into the right hand,
and the hitch is ready to pass over the object. Shown in 15-D.
Tc. Snubbing hitch . — This knot is used for securing tem-
porary guys to poles and trees. See figure 16.
(1) Pass the rope around the pole or object twice, then
turn the free end around the standing part inside the bight.
Shown in 16-A.
(2) Take another turn inside the bight as shown in 16- A.
(3) Complete the hitch with two half -hitches as shown in
16-B and 16-C.
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Figure 17
l. Catspaw . — This knot is used in attaching a rope to the
hook of a block. It provides a double rope over the hook of
the block and permits a load to be carried on either end of
the rope. See figure 17.
(1) Grasp the rope as shown in 17-A.
(2) Drop rope between the hands to form a bight, then
twist the hands, thus forming two loops as shown in 17-B.
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(3) Twist each loop a half turn in the direction indicated
by the arrows in 17-C.
(4) Twist each loop another half turn and hang loop on
the hook. The completed hitch is shown in 17 -D.
m. Platform guy knot . — This knot is used in securing the
ropes, leading from the splicers platform to the pole, ladders,
and other supports. See figure 18.
(1) Select the side of the platform from which the splicer
is to work. Grasp loose end of guy rope from opposite side
of the platform and pass it around the pole, about 3 feet
from the ground and pull tight. Keep the guy rope dear of
steps and avoid blocking the dimbing space.
(2) Take a turn over and around the standing part of the
rope with the loose end, and pull to the desired tension.
(3) Pass the rope around the pole so that it crosses the
first turn. Hold the free end of the rope in this position to
snub pull on the platform. Pull to the desired tension.
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Lesson 8
Shop Work
(4) If the free end is too long to handle, double the rope
as shown in 18-D.
(5) Secure with two half-hitches on the standing rope.
The completed knot is shown in 18 -F.
(6) The other guy rope shall be secured on the same side
of the pole, near the turns of the first guy rope. Since this
guy leads from the opposite direction, it must necessarily be
snubbed in the opposite direction.
Figure 19
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Rope, Splices, Knots and Blocks
Lesson 8
». Lashing . — Lashings are used when a temporary attach-
ment is desired. The ease of attaching and detaching and the
safety factor, will determine the type of lashings that will be
used in various conditions. Lashings to be used where the
pull is perpendicular to the axis of the pole and where the
pull is parallel to the axis of the pole are shown in figure 19.
The rope used for lashing should be of the size shown in
table 2, and in good condition. Rope which has been discard-
ed as unsafe for pulling line or for use in blocks, should not
be used for lashings. When lashing a block to a pole, the
number of turns around the pole shall be the same as the
number of turns through the hook.
TABLE 2
Size of rope lashings
Size of block Required number of turns through
hooks of blocks for the following
sizes of rope
%
Vs
% or % 1 (inches)
3 inch
1 sheave
2
3 inch
2 sheave
3
2
3 inch
3 sheave
4
3
4 inch
3 sheave
4
3
6 inch
3 sheave
4 3
8 inch
3 sheave
4
6 inch
Snatch
4 3
8 inch
Snatch
4
465422 0 - 42 -9
127
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Lesson 8
Shop Work
Figure 20 shows the type of lashing to be used when lash-
ing two poles together. Figure 20 also shows the lashing
used in securing a ladder to a messenger. A ladder should
not be moved after it has been lashed to the messenger.
Square
Knot
Lashing to be made
on both side rails .
Wrap hand line around
strand, rung, and side rail
of ladder as shown ,
using 3 or 4 turns of
1 in. or 2 in. hand line.
Then wrap one end 3 turns
around strand . Tie ends
together with square Knot.
ri'333 6
Figure 20
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Rope, Splices, Knots and Blocks
Lesson 8
4. Blocks. — a. General . — The parts of a block are the shell,
sheave, hook, becket, becket bolt, bushing, cotter pin, center
strap, outside strap and roller bushing. See figure 21 (a) .
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Lesson 8
Shop Work
The terms commonly used in reference to blocks are as
follows:
Tackle. — An assembly of ropes and blocks. The rope is
commonly called the fall.
Running block. — The block attached to the object to be
moved.
Standing block. — The block attached to the fixed support.
Overhaul blocks. — To separate or spread blocks in a
tackle.
Run in block. — To bring blocks closer together.
Chock-a-block. — Blocks of a tackle in contact.
Standing end. — End of a rope fixed to the block.
Running end or fall line. — The free end of the rope in
tackle.
Return. — The rope between two blocks.
Reeving of blocks. — To pass rope over the sheaves of
blocks to obtain mechanical advantage.
b. Standard blocks . — Standard blocks are furnished in the
sizes as shown in table 3, and are equipped with the open
type hook unless ordered with shackle. Table 3 shows the
standard sizes and types of blocks, together with their work-
ing strength and the size of rope to be used. The size of
blocks is determined by the length of their shell and the
number of sheaves.
TABLE 3
Size Number of Working Size Suggested Maximum had Maximum had
of sheaves strength of length (ft) that may be that may be
blocks of hooks rope applied h new applied h new
(lbs.) small rope large rope
* **
3 inch
i
2100
for*
50
400
700
3 inch
2
2300
forf
75
400
600
3 inch
3
3900
fori
100
400
650
4 inch
3
4600
iorf
150
700
800
6 inch
3
8600
i
200
1400
8 inch
3
12000
i
275
2300
* Maximum load permitted on hooks.
** The smaller size rope shall be used, in general, where the
weather conditions are humid.
130
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Rope, Splices, Knots and Blocks
Lesson 8
The hooks of the standard and snatch blocks have been
designed so that they start to open at approximately 70 per-
cent of the maximum load they will carry, thus acting as a
visible safety link to warn against overstressing, before
complete failure of the block. To obtain the maximum
strength, the load should be applied at the lowest point of
curvature of the hook. The maximum working strength of
the hooks, as given in table 3, is based on the load being
applied at the lowest point of curvature of the hook. It is
impracticable to give the strengths of the hooks for all
conditions, as the load may not always be applied in the
same manner. When blocks are in use, the hook should be
under observation at all times, to determine if the hook has
the required strength to withstand the applied load.
c. Manila rope snatch blocks . — Snatch blocks are furnish-
ed in two sizes: 6-inch or 8-inch. The hooks have a working
strength of 11,000 pounds and 17,000 pounds respectively.
This working strength is approximately 70 percent of the
maximum load they will carry. The 6-inch block is intended
for use with %- or % -inch manila rope and the 8-inch block
is intended for use with 1- or l^-inch manila rope. Snatch
blocks are illustrated in figure 21 (b) .
d. Reeving of blocks . — It is important that blocks be reev-
ed properly to have them operate to the best advantage and
avoid jamming, which would lose time and possibly cause
an accident. The 2- or 3-sheave blocks shall be reeved in
either of the ways as shown in figures 22 and 23.
When reeving with new rope, place the rope under slight
tension. The fall line should emerge from the center sheave
of a 3-sheave block. This causes the hoisting strain to
come on the center of the block, preventing it from turning
and cutting the rope on the block shell. When reeving by this
method, figure 22, the sheaves of the two blocks should be
placed at right angles to each other.
Where there is a possibility of the rope being tangled,
when reeving by the method shown in figure 22, the blocks
may be reeved left over right, as shown in figure 23.
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Lesson 8
Shop Work
Figure 22
e. Rigging . — The type of rigging used will depend upon
the weight to be handled and the available motive power.
The simplest rigging, that will adequately perform the work,
should be selected. Luffing tackle is a commonly used type
of rigging. A simple definition of luffing tackle is; additional
tackle (blocks and necessary rope) , attached to the fall line
of the main tackle (tackle attached to the load). Figure 24
shows luffing tackle used two different ways, lifting a load
and hauling a load.
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Lesson 8
Figure 23
When the load to be handled is greater than can be
handled safely by the workmen, then block and tackle shall
be used to gain a mechanical advantage. For practical pur-
poses, the weight capable of being lifted is equal to the ap-
plied force times the number of ropes leaving the movable
block. For example, if a man can exert a force of 130 pounds
on the fall line of a three sheave tackle, he will be able to
lift 6 times 130 or 780 pounds. This assumes the fall line
leaves the fixed block, as in lifting a load, figure 24. If the
fall line leaves the movable block as in hauling a load, figure
24, the same man can lift 7 times 130 or 910 pounds.
133
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Lesson 8
Shop Work
LIFTING A LOAD
r*-To Anchorage
€370 Pounds
Standing Block
Running Block
To Load
Intermediate Bowline
pr Catspaw.
If a second purchase is
required use a farmers'
knot or taut rope hitch.
130 Pounds exerted by
one man on this fall
line can lift a load of
5460 pounds. See
Part 11 for explanation
of forces as shown.
Luffing Tackle
To Anchorage
5460 Pounds
*780 Pounds
HAUUNG A LOAD
Figure 24
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TL-3315
Rope, Splices, Knots and Blocks
Lesson 8
/. Selecting the proper size blocks for the work to be per-
formed . — To do this it is necessary to know the approximate
weight to be handled, the motive or lifting power available
and the strength of the hooks of the standard blocks. Know-
ing the load and the available power, calculate the number
of sheaves required, by dividing the load by two times the
power. If this result is three or less, select one of the stand-
ard blocks with the number of sheaves as calculated and a
hook strong enough to withstand the load. If this result is
over three, it will be necessary to select a system of rigging
from the standard blocks available. This rigging will require
luffing tackle, which in general is a 3-sheave arrange-
ment. See figure 24. When using luffing tackle, remember
that for practicable purposes, the stress in the fall line of the
tackle attached to the load, is equal to the force applied to
the fall line of the luffing tackle, times the number of ropes
leaving the movable block of the luffing tackle, which will be
six or seven.
To determine the number of sheaves required in the tackle
attached to the load, divide the load to be lifted by twice the
applied power. Select a block with a hook capable of with-
standing the load. Be sure that the load applied to the fall
line of the tackle attached to the load, is not too great for
the size of the rope as specified in table 1.
Example: Refer to figure 24, (lifting a load) . 5460 pounds
to be lifted by one man who can exert a force of 130 pounds.
To find the number of sheaves required 5460/2 x 130
equals 20 (approximate) .
The number of sheaves required is greater than three,
therefore luffing tackle is required. Three-sheave blocks will
be used in the tackle attached to the load, with the fall line
leaving the fixed block, which makes the man capable of lift-
ing 6 times 130 or 780 pounds.
Number of sheaves required in luffing tackle 5460/2 x 780
equals 2 plus, (use 3)
Using 3-sheave blocks in the luffing tackle, the fall line
leaving the moving block, the man can lift 7 times 130 or
910 pounds.
135
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Lesson 8
Shop Work
With a 910 pound pull exerted on the fall line of the main
tackle (by use of the luffing tackle) , the man will be able to
lift 6 times 910 or 5460 pounds.
When the approximate weight and motive power is known,
the proper size blocks can be selected from table 3, in most
cases.
5. Safety precautions. — Safety to life and property requires
that rope and blocks be well cared for. A few precautions, in
addition to those previously listed in the text are given
below:
(1) A hook that has begun to straighten shall be dis-
carded immediately.
(2) Do not use blocks with sheave holes too small to give
clearance, between the sheaves and the sides and top of the
shell.
(3) When moving from one location to another, do not
drag rope on the ground.
(4) Do not stand unnecessarily close to, and never strad-
dle rope under tension.
(5) Do not stand in the inside angle, or in the path of rope
being paid out or under tension.
(6) Do not use frozen rope.
(7) The hand line shall not be attached to the belt, when
working on poles. Make it fast to the crossarm or to the pole.
(8) Hand line or other rope secured aloft, when not in
use, shall be secured at a point near the ground to prevent
it from being blown about.
(9) Rope shall be placed as to create no obstruction on
highways or thoroughfares, unless unavoidable; in that case,
place a man to warn traffic.
(10) Gloves should be worn when handling new rope to
avoid the possibility of injury from fibre slivers.
136
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Rope, Splices, Knots and Blocks
Lesson 8
Review questions. —
1. Name the various parts of a block.
2. How are the sizes of blocks determined?
3. What is the weakest part of the block?
4. In what way does a snatch block differ from other
blocks?
5. What is the process of threading rope through blocks
called?
6. What is the fall end of rope?
7. What is the term applied to a set of blocks, attached
to the fall line of the main tackle?
8. What should blocks be inspected for, to determine their
condition?
9. How and where should rope be stored?
10. How should new rope be removed from the original
coil?
11. What should be done to rope before it is cut?
12. What is the purpose of a serving and a crown splice?
13. What two advantages does the long straight splice
have over the short straight splice?
14. What is the eye splice used for?
15. What are the two great advantages of the bowline?
16. What is the block becket bend used for?
17. What is the snubbing hitch used for?
18. What knot is used for securing the guy ropes of cable
splicers platforms?
19. What are lashings?
20. Should the bearings be oiled on a sheave equipped with
roller bushings?
137
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Lesson 8
Shop Work
LESSON 8
LABORATORY
Tools and materials. —
1 ea. Knife TL-19
•Rope for reeving, knot tying, splicing.
•Friction tape, lacing twine.
Items marked • are not placed on the memorandum receipt.
Do not cut the reeving nor the knot tying ropes.
Blocks for reeving will be found in the class room.
Operation 1 . — Inspect the blocks selected and list the
faults below.
Ins. check
Operation 2 . — Reeve the two 3-sheave blocks as shown
in figure 22.
Ins. check
Operation 3 . — Reeve the 3-sheave and the 2-sheave block
as shown in figure 22.
Ins. check
Operation k - — Reeve the two 2-sheave blocks as shown
in figure 22.
Ins. check
Operation 5 . — Using short pieces of rope make the follow-
ing: a serving splice, a crown splice, an eye splice and a short
straight splice. Submit to the instructor.
Ins. check
Operation 6 . — Practice tying the following knots: the fig-
ure 8 knot, the square knot, single bowline, intermediate
bowline, double bowline, bowline on a bight, block becket
bend, clove hitch, snubbing hitch, catspaw, and platform
guy knot. These knots should be learned well enough so that
the student can tie any of them from memory when called
upon to do so by the instructor.
Ins. check
138
U S. GOVERNMENT PRINTING OFFICE : 1942
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UNIVERSITY OF CALIFORNIA
[A. G. 062.11 (8-11-42).]
By order of the Secretary of War:
G. C. MARSHALL,
Chief of Staff.
Official:
J. A. ULIO,
Major General,
The Adjutant General.
Distribution:
C and H 11 (2).
(For explanation of distribution symbols see FM21-6.)
U. S. GOVERNMENT PRINTING OFFICE: It41
139
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