Shop Work

[Shop Work]
[From the U.S. Government Publishing Office, www.gpo.gov]

w 1.35: ll-453,c.3
U OF NT LIBRARIES 76203
TM 11-453
WAR DEPARTMENT
TECHNICAL MANUAL
SHOP WORK
March 11, 1942

Shop Work
PREFACE
/
This text has been prepared by the Enlisted Men’s Department 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.
i
Shop Work
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 ...........................;.. . 27
5—Soldering ................................... 45
5A—Wiring of Radio Equipment, Cords and Plugs.... 65
6—Woodworking ................................. 79
7—Miscellaneous Tools.......................... 92
8—Rope, Splices, Knots and Blocks.............. 99
ii
TM 11-453
TECHNICAL MANUAL1 WAR DEPARTMENT,
No. 11-453 J 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 usually 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 the 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. Care 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. Wipe all 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
1
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 expert, 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 sharpened 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 preserved during the grinding process by dipping it frequently into a can of water to keep it cool. Grindstones and carborundum 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.
2
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 pressure, 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.
Direction S - ••• —Lry—issgsg-
of motion | _____I U
,JL
- IsEZZSSS&X TL.-W7
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 cutters.—Plane cutters, chisels, gouges and similar single bevel cutting tools should first be ground square on the carborundum wheel. Check with a trysquare, 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 removed 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
3
Lesson 1
Shop Work
moderate amount of pressure and move the tool over the entire surface of the stone with a rotary motion as illustrated in figure 2.
of motion• ff -it
TL-3258
Figure 2
Use as small a circle as possible, as this gives better control over the tool. A rocking motion should be avoided, as this soon destroys the hollow grind obtained from the carborundum 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 probably 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.
4
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 surfaces 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.
a 0
,'rI ri
Tip of blade straight I I__ „
I /I [/ but not square. \ -Rounded tip
■ ■ I yf I // Raises out of slot
--— Turns out of slot, wood damaged, and slot marred.
'-'=~------- " T1-2183-1
Figure 3a
ffl .fl '
n
( ) i/Z 4 U
\ / /- Width of tip of blade : ■ ■ >77 Center line of shank
___I /X too large. J/ ./, t-~X- A / out of line with center line of screw.
r—^ears wood around — Tip slips out of slot,
screw head. wood and slot
' gSXXsXWJyflzT marred.
.'XZT— - TL- g/83-2
Figure 3b
5
Lesson 1
Shop Work
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 screwdriver in a pocket, where injury may result through exposure 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.
6
)l H (1
Too thin a tip, corners l| I I
I turn over and then j I I Tip too thick, does
I I tip slips out of slot ' । a, I not seat property
lU / \ pl in slot. Top of
e is III scr6w hea^
| ■ l| I I I I be sheared off
1ST (31
Screws with damaged slots are difficult to remove. Difficult jobs take extra time.
Extra time increases maintenance costs TL"2IS3-3
Figure 3c
S H SB
/ \ VIj Beveled tip raises / \ / \
( ) out of slot. I I I /
\ I I | Slot damaged I I \ I
LJ \1 VI
_____ ' ~~-~____Broken tip concentrates the —___ —________ stresses in the remaining
portion of the blade. This '— may *3r'n® ab°ut breakage
_____ of the other side of the tip
------------------ TL-2183-4
Figure 3d
Classification, Care and Maintenance of Tools Lesson 1
The maintenance of twist drills and wood bits is an exacting 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 serviceable 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.
7
Lesson 1
Shop Work
RESTRICTED
LESSON 1
LABORATORY
Tools and materials.—
Oilstone
Carborundum stone
Knife, TL-29
Wood chisel
Plane cutter
* Oilcan
*Rags
Items marked * are not placed on the memorandum receipt.
Procedure.—
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 instructions 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 requires grinding, consult the instructor. Submit sharpened tools to instructor for approval.
...............Ins. check
Operation 4-—Examine one of the sets of screwdrivers displayed on bulletin board.
...............Ins. check
List the faults found below:
1.
2.
3.
8
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 screwdriver 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: sidecutting, 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 cutters, 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 crushing (use the heel), gripping, wire splicing, wire cutting and insulation stripping. When removing insulation, do not permit the jaws to touch bare wire. Never cut solid wire completely apart with pliers, as this may damage the cut
9
Lesson 2
Shop Work
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 6’A-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, attaching wires to terminals and punchings, skinning and splicing small wires.
Wire insulation is crushed with the long-nose pliers, providing 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.
10
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. Field 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.
\_XJ TL.-/7/4
Figure 1
c. Crush and remove insulation from long and short conductor as indicated in figure 2.
/ \
/
\ 4A '
^>**,ii**,*ia— \ J*?
"—Crush 4 _
TL-17/5
Figure 2a
11
Lesson 2
Shop Work
sss#**^ TL-I7I6
Figure 2b
( «i
-----Crush4’~^rH ( 6'
i 0
^^^ffiasssaaS‘ TL-1737
Figure 2c
TL-I7I7
Figure 2d
12
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.
/J /"Lx / -*u rn
/ TL-/7/9A
Figure 4a
Cut tail flush with rubber insulation
\_ — t
I \ TL-I720A
Figure 4b
13
Lesson 2
Shop Work
14
{rubber % turns on rubber
j" X________-
IBlllh_______lllllll
TL-I7Z5
Figure 4c
•--------------6"----------—---
Figure 4d
8. Combination seizing wire splice.—This splice is used to splice a stranded conductor insulated wire to a solid conductor 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
.SEIZING W!RE 12" LONG
STRANDED W/RE-y
SOLID CONDUCTOR^ SEIZING WIRE J
WRAPPINGS EXTENDED ONTO (SOLID CONDUCTOR
TL-696J
Figures
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 combination 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.
aa TL-3260
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, composed 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 close contact with each other. Cut the ends of the buttons off as closely 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 circuit without causing interruption to service.
501497 0-43 -2
15
Lesson 2
Shop Work
16
.>
Button.,___Neck________,.
/turn .
TL.699„ At least 5 turns^Cutoff end
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 1^2 inches. Make the splice as illustrated in figure 8.
H—---------------12 "or more---------m
I X,
'^^^ConductorA^^
Y,
FIRST STEP
rEnd to be discarded
r r
•Square Knot
SECOND STEP TL-/828A
Figure 8
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.
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 V2 inch of rubber insulation has been covered. Reverse the wrap toward the left until y2 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
Rubber tape—M Friction tape-----
Cover one meh of braid
TL-1723
Figure 9a
Co ver rubber insulation onia .........
TL-172Z
Figure 9b
17
Lesson 2
Shop Work
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.
18
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 3.—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 information sheet, tape the splices made under operations 1 and 3.
............... Ins. check
19
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.
<^\ \ 9E ) ] Se /
9 5 * G0\
zf L ? ? ? TL-J226
Figure 1
2. Wire gauges.—The wire gauge is a tool used for measuring 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
20
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.
Shaft—< Lock Nut-. Thimble —Speeder and
. .. \ ~ „ \ _ , \ Friction Slip—.
^niaL—^\So7/7o7e^ arret\
yp) v X—? ., \ n- f Vft—JL
rmi Wf |i -IP®
\ Frame /
___' TL-443
Figure 2
3. The micrometer caliper.—This tool is used to measure the diameters of objects in thousandths of an inch. The illustration given in figure 2 shows the method of measuring and names the major parts of the tool. The micrometer, in conjunction 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.
21
Lesson 3
Shop Work
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 cloth 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?
22
Measuring and Gauging Lesson 3
8. What is the thickness gauge used for?
Note.—In order to determine the area of a given cross section 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. 4602 equals 211,600 circular mils, the area of the cross section.
TABLE 1
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 merican or Brown & Sharpe Co. Birmingham, or Stubs iron wire Washburn & Moen Mfg. Co. or Roebling English legal Standard Stubs steel wire U S Standard 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 x .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
23
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 merican or Brown & Sharpe Co. Birmingham, or Stubs iron wire Washburn & Moen Mfg. Co. or Roebling English legal Standard Stubs steel wire U S Standard gauge for sheet and plate iron and steel No. of wire gauge
17 .045257 .058 .0540 .056 All .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 .148 .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
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.
25
Lesson 3
Shop Work
Diameter in mils Ga. Thickness in mils Ga.
1.................. 1-------------------------
Wire 2..................... Plate 2..................
Samples 3.................. Samples 3----------------
......:_______Ins. check
Operation 4.—Examine the speed indicator. The instructor 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 bulletin board, and record the results below.
ABC (Underline the set used)
1.............. 2.......................
3.............. 4........................
......................Ins. check
26
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 shoulder 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.
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—-W