engine room tools part 2

8/11/2019 Engine Room Tools Part 2

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ENGINE-ROOM TOOLS, PART 2

91. Machine Screws.-The term "machine screw" is generally used to designate

the small screws that are used in tapped holes for the assembly of metal parts.

The types of machine screws that are ordinarily encountered are shown in Fig.78. Most of these screws are made of steel or brass, some being plated to resist

corrosion. They are also made of stainless steel.

FIG. 78. MACHINE SCREWS.

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There is a great variety of diameters, lengths, and head shapes manufactured.

The thread diameter, length in inches, head shape, material from which made,

and the type of finish, must therefore be included in a complete description of a


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machine screw.

Occasionally machine screws with specially shaped heads, as shown in Fig. 79,

are used aboard ship. Most of these screws require special tools for driving and

removing. In some cases the tools are included in a kit that comes with the

machine on which the screws are used.

FIG. 79. SPECIAL MACHINE SCREWS.

Machine screws are driven and removed with a screwdriver or wrench,depending on the type of screw head. Hexagon, or hex, heads are turned with

socket wrenches; slotted heads are turned with plain screwdrivers; socket heads

require an Allen-type wrench; and Phillips heads require special Phillips

screwdrivers. Holes for fillister-head screws must be counterbored so that the

head of the screw is flush with or below the surface.

92. Cap Screws.-Cap screws, sometimes called "tap bolts," perform the same

functions as machine screws. They are generally used without nuts and are

screwed into tapped holes. Their sizes range up to 1 inch in diameter and 6

inches in length.

Cap screws may have square, hex, flat, button, or fillister heads, as illustrated in

Fig. 78. Fillister heads are best for use on moving

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parts because such heads are sunk into counterbored holes. Hex heads are

usually used where the metal parts do not move.

The strongest cap screws are made of alloy steel. Cap screws made of stainless

steel are often specified on machinery exposed to salt water, which would soon

corrode and "freeze" the threads of ordinary steel screws.

Some cap screws have small holes through their heads. A length of wire, called a

safety wire, is passed through the holes in all of the screws in a group and is

fastened at the ends, thus preventing the cap screws from coming loose.

93. Sheet-Metal Screws.-The screws shown in Fig. 80 are used to hold together

sections of sheet metal, fiber, plastic, etc., and are known as sheet-metal screws.

They are especially useful aboard ship when applying sheet-metal covering over


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insulation. Type A has a sharp point and resembles a wood screw, except that

the threads extend to the head of the screw. Type Z screws have blunt points

and may be used with heavier material. A special "self-tapping" sheet-metal

screw has a tap end that cuts threads as the screw is inserted.

Holes for sheet-metal screws should be drilled or punched to about the same

diameter as the core of the screw used. The screws are available in a variety ofhead shapes, as shown in the illustration.

FIG. 80. SHEET METAL SCREWS.

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FIG. 81. COMMON TYPES OF BOLTS.

94. Machine Bolts.-Machine bolts, Fig. 81, are made in a variety of diameters,

lengths, thread pitches, and head shapes. They are furnished in three grades:

machine finished, semi-finished, and rough. Diameters range from 3/16 inch to 3/4

inch, and lengths from 1/2 inch to 30 inches. The larger bolts are usually made

up to fit as needed instead of carrying them in stock.

Machine bolts are used to hold together frames and structures, particularly

those which must be easily dismantled. Some bolts have holes drilled near the

end of. the threaded part for cotter pins or safety wire. The nuts used on

machine bolts may be either square or hexagonal, and the bolt heads also may

be of either type. Washers are usually used with these bolts.

95. Stove Bolts.-Stove bolts are small, and were developed for use on stoves, as

the name suggests. They can be used for many other jobs, however, where


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great accuracy and strength are not required and where there is no great

amount of vibration to shake the nuts loose. Stove bolts have special coarse

threads which make a free fit with the threads of the square nuts used on them.

96. Carriage Bolts.-Carriage bolts usually have round heads, with short square

shanks just under their heads. This square portion prevents the bolt from

turning. Their chief use is in wood structures, but they may be used with metal.Square nuts and flat washers are used on carriage bolts and are supplied with

them.

97. Studs.-Studs, or stud bolts, have both ends threaded, but one end takes a

nut while the other is screwed into a tapped hole.

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The use of a stud is really a safety precaution, because the nut may still be

removed, even if the end that is screwed into the casting is "frozen." Because

studs are commonly used in castings, they generally have coarse threads.

98. Stud Driver.-A stud driver, Fig. 82, is used to screw studs into place or to

remove them without damaging the threads. It is also very useful when working

on studs in inaccessible places. The driver consists of a square or hexagonal

piece of steel or other metal which has one end drilled and tapped to receive

the stud and the other end drilled and tapped for a setscrew.

FIG. 82. STUD DRIVER.

If the stud is to be installed in a hole, the stud should be screwed into the driver,

and the setscrew tightened firmly against the stud. However, if the stud is

already started in the hole, screw the driver on the stud and tighten the

setscrew. In both of these operations the stud and stud driver are locked

together, and a wrench is then used on the body of the driver to turn the stud.

If a stud driver is not handy when needed, a substitute can be made by screwing

2 nuts on the stud, and locking them together by applying a separate wrench toeach nut. To unscrew the stud, a wrench should be applied to the inside nut. If

the stud is being tightened, a wrench is applied to the outside nut.

99. Screw Extractor.-At times a screw or stud will break off in a hole and must

be extracted. The best method of doing this is to use a screw extractor, or "easy

out." First drill a hole in the broken screw or stud a little smaller than its body

diameter, so that the thread will not be damaged. Then insert the extractor in

the drilled hole, tapping it lightly. (Extractors are marked with the size drill

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with which they are to be used.) The screw extractor is tapered and has sharp

ridges, and when a wrench is applied and the extractor turned

counterclockwise, the ridges will grip the broken part so that it can be screwed

out of the hole. A screw extractor inserted in a broken stud is shown in Fig. 83.

FIG. 83. USE OF SCREW EXTRACTOR.

100. Nuts.-Several kinds of nuts are shown in Fig. 84. These must always be

used with some kind of bolt or stud, so that the two pieces, nut and bolt or nut

and stud, exert holding force by the strength of their threads. The combination

is suited to assemblies that may have to be removed or taken apart.

Square and hexagonal nutsare standard, but they are supplemented by special

nuts. One of these is the jam nut, or locknut, used above a standard hex nut to

lock it in position. It is about half as thick as the standard nut, and has a washer

face.

Castellated nutsare slotted so that a cotter pin may be pushed

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FIG. 84. NUTS.


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through the slots and a hole in the bolt. This provides a positive method of

preventing the nut from working loose. They are usually used with machine

bolts.

Wing nutsare especially useful where there is frequent occasion for hand

adjustment. Capor acornnuts are used where appearance is an importantconsideration. They are usually made of brass, which is then chromium-plated.

Thumb nutsare knurled, so that they may be turned by hand for easy assembly

and disassembly.

Elastic stop nutsare used where it is imperative that the nut does not come

loose. These nuts have a fiber or composition washer built into them. When the

nut is tightened, the washer is compressed automatically against the screw

threads to provide holding tension.

101. Washers.-Washers are often placed under nuts or bolt heads to protect thepieces being fastened or to make tightening up easier. Three kinds of washers

are shown in Fig. 85.

Flat washersare used to back up bolt heads and nuts and provide larger bearing

surfaces. They also prevent damage to the surfaces of the metal parts through

which a bolt passes.

FIG. 85. WASHERS.

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Split lock washersare used under nuts to prevent loosening by vibration. The

ends of these spring-hardened washers dig into both the nut and the work to

prevent slippage.

Shakeproof lock washershave teeth or lugs that can grip both the work and the

nut. After the nut has been tightened on this type of washer, half of the lugs are

bent against the nut and the other half bent in the opposite direction against the

work, if possible, thus obtaining the locking action. Several patented designs,

shapes and sizes are obtainable.

102. Threads.-Threads are helical ridges cut into screws, nuts, bolts, or in the

walls of a hole, so that the action of turning gives an endwise as well as a rotary

motion. A thread is either an outside (male) thread, or an inside (female) thread.

An understanding of the terms used in connection with screw threads is

extremely important. The following definitions are therefore given, and refer to

Fig. 86.

Angle of thread. The angle of thread is the angle included between the sides of

the thread, measured in an axial plane.

Half angle of thread. The angle included between a side of the thread and the

normal (90 from the axis), measured in an axial plane.


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Lead. The distance a screw thread advances axially in one turn.

Major diameter. The largest diameter of the thread of the screw or nut.

Minor diameter, or root diameter. The smallest diameter of the thread of the

screw or nut.

Pitch diameter. On a straight screw thread, the diameter of an imaginary

cylinder, the surface of which would pass through the threads at such points as

to make equal the width of the threads and the width of the spaces cut by the

surface of the cylinder.

Pitch. The pitch of a thread is the measured distance from the crest of one

thread to the crest of the next adjacent thread. The number of threads per inch,

such as 8, 10, 12, etc., is equal to 1 divided by the pitch, in inches. The diameter

and the pitch (or number of threads per inch) must be known in specifying orcutting threads.

103. Threads having major diameters of less than 1/4 inch are used on machine

screws. The diameters range from 0.060 inch for

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FIG. 86. SCREW THREAD TERMS.

size "0," to 0.216 inch for size 12, and vary 0.013 inch from one size to the next.

Threads having major diameters of 1/4 inch to 5/8 inch vary in diameter by 1/16


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inch from size to the next. Threads with diameters of 5/8 inch to 1 1/4 inches

vary in diameter by 1/8 inch. Table I includes data concerning standard threads

up to 1 1/4 inches in diameter.

104. Thread Forms.-The four most common types of screw threads are the

V-thread, the American National thread, the Square thread, and the Acme

thread. The same rules for diameter and pitch apply to all types of threads.

The sharp V-thread, Fig. 87, has serious disadvantages and is

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TABLE I.

AMERICAN NATIONAL THREADS

(Thread and Tap Drill Sizes)

Size and

Threads

per inch

Thr'd

series

Major

diameter

(inches)

Root

diameter

(inches)

Tap drill to

produce approx.

75% full thread

Decimal

equivalent

of tap drill

0-80 N. F. 0.0600 0.0438 3/64 0.0469

64 N. C. 0.0730 0.0527 53 0.0595

72 N. F. 0.0730 0.0550 53 0.0595

2-56 N. C. 0.0860 0.0628 50 0.0700

64 N. F. 0.0860 0.0657 50 0.0700

3-48 N. C. 0.0990 0.0719 47 0.0785

56 N. F. 0.0990 0.0758 45 0.0820

4-40 N. C. 0.1120 0.0795 43 0.0890

48 N. F. 0.1120 0.0849 42 0.0935

5-40 N. C. 0.1250 0.0925 38 0.1015

44 N. F. 0.1250 0.0955 37 0.1040

6-32 N. C. 0.1380 0.0974 36 0.1065

40 N. F. 0.1380 0.1055 33 0.1130

8-32 N. C. 0.1640 0.1234 29 0.1360

36 N. F. 0.1640 0.1279 29 0.1360

10-24 N. C. 0.1900 0.1359 25 0.1495

32 N. F. 0.1900 0.1494 21 0.1590

12-24 N.C. 0.2160 0.1619 16 0.177028 N. F. 0.2160 0.1696 14 0.1820

1/4-20 N. C. 0.2500 0.1850 7 0.2010

28 N. F. 0.2500 0.2036 3 0.2130

5/16-18 N. C. 0.3125 0.2403 F 0.2570

24 N. F. 0.3125 0.2584 I 0.2720

3/8-16 N. C. 0.3750 0.2938 5/16 0.3125

24 N. F. 0.3750 0.3209 Q 0.3320

7/16-14 N. C. 0.4375 0.3447 U 0.3680

20 N. F. 0.4375 0.3726 25/64 0.3906


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1/2-13 N. C. 0.5000 0.4001 27/64 0.4219

20 N. F. 0.5000 0.4351 29/64 0.4531

9/16-12 N. C. 0.5625 0.4542 31/64 0.4844

18 N. F. 0.5625 0.4903 33/64 0.5156

5/8-11 N. C. 0.6250 0.5069 17/32 0.5312

18 N. F. 0.6250 0.5528 37/64 0.5781

3/4-10 N. C. 0.7500 0.6201 21/32 0.6562

16 N. F. 0.7500 0.6688 11/16 0.6875

7/8-9 N. C. 0.8750 0.7307 49/64 0.7656

14 N. F. 0.8750 0.7822 13/16 0.8125

1-8 N. C. 1.0090 0.8376 7/8 0.8750

14 N. F. 1.0000 0.9072 15/16 0.9375

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FIG. 87. SHARP V AND AMERICAN NATIONAL THREADS.

seldom used. The sharp crests and roots are hard to cut accurately; the crests

are easily dented and chipped; and the roots become clogged with dirt and bits

of metal.

The American National thread, also shown in Fig. 87, resembles the sharp

V-thread, except that the crests and roots are flat. The length of this flat portion,

of both crest and root, is 1/8 of the pitch distance. Because of the design,

American National threads are not easily damaged and the roots are easily

cleaned. This type of thread is the one generally used on the many bolts and

nuts found in a ship's installation.

America National threads are standardized into 2 series, National Coarse (N.C.)

and National Fine (N.F.). The coarse thread


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Fig. 88. SQUARE AND ACME THREADS.

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series is used for rough work on heavy materials, while the fine thread series is

used on small bolts, machine screws, adjusting mechanisms, etc.

The Square thread, shown in Fig. 88, is strong and efficient. It is used on the

tightening screws of vises, clamps, and jacks.

The Acme thread is a heavy-duty thread whose sides form an angle of 29

degrees with each other. This type of thread can withstand heavy strains and

loads, and is easier to machine than Square threads.

105. Most threads are right-hand threads, that is, they advance when turned

clockwise. Left-hand threads, however, are required by some machines and

installations. They advance when turned counterclockwise. Left-hand threads

are often labeled so that they will not be turned the wrong way. Right-hand taps

and dies cannot be used to cut left-hand threads; a special left-hand tap and die

is necessary.

106. The fit of threads depends on the clearance between the threads of mating

parts, the four different fits being as follows:

No. 1.-Loose fit; No. 2.-Free fit; No. 3.-Medium fit; No. 4.-Close fit.

The No. 1 and No. 2 fits have considerable play and are used on stove bolts and

bolts used for rough construction.

The No. 3 fit is the one specified for machine parts, engine bolts and most

threaded parts. If a matching bolt and nut have very little play and can just be

turned with the fingers, the threads probably have a No. 3 thread. However, if it

is necessary to use a wrench without much pressure, it is a No. 4 close fit. This fit

is used for the threaded parts of mechanisms that must be extremely accurate.

Thread fits are often stated on blueprints, together with the thread's major

diameter, the threads per inch, and thread series. Such a note would appear as


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-3/8-16 N.C.-3. The first number indicates the diameter, in inches; the second

number, the number of threads per inch; and the last number, the thread fit.

The number of threads per inch of a bolt or screw may be determined by using

a screw pitch gage, shown in Fig. 89. This gage

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FIG. 89. SCREW PITCH GAGE.

has a number of pivoted, knife-like blades whose edges are cut to represent the

various thread pitches. To use the gage, select and try the blades in turn until

one fits the thread exactly, then read the number stamped on that blade.

107. Taps and Dies.-Taps and dies are tools used for cutting screw threads.

Taps are used to cut inside threads and dies to cut outside threads.

Taps and dies can be classified under the following headings: 1. Type of thread

formed, such as N.F. or N.C.; 2. Diameter of the screw formed or hole tapped; 3.

Number of threads per inch.

The two kinds of taps in common use are known as standard hand tapsand

machine screw taps. Standard hand taps are made for cutting threads from 1/16

inch up to 4 inches in diameter; machine screw tap diameters are designated by

numbers ranging from No. 0 (smallest) to No. 30 (largest) to fit the

corresponding sizes of machine screws.

In order that there may be enough metal in the hole to provide material into

which the threads can be cut, the hole must be drilled smaller than the major

diameter of the tap threads. The size of the drill to be used can be computed by

taking 75% of the difference between the major and minor diameters, andsubtract this amount from the major diameter. The resultant thread is

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known as a "75% thread," and is generally used because it is only 5% less

efficient than a full depth thread.

The most convenient method of determining the size of tap drill to be used is to

consult a tabulation of thread and tap drill sizes such as that given in Table I.

108. Sets of taps.-Hand taps are usually provided in sets of three for each


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diameter and thread combination, as shown in Fig. 90. Each set contains a taper

tap, aplug tap, and a bottoming tap. The taps in each set are identical in diameter

and cross section.

FIG. 90. TAPS.

The taper tap may be used for internal threading where the work permits the

tap to be run entirely through. When the taper tap cannot be run through the

work, the diameter will be so small near the bottom of the tapped hole that the

screw or bolt will not screw down as far as it should. In this case a plug tap isused after the taper tap is removed. If full diameter threads are desired all the

way to the bottom of the hole, the plug tap is followed by a bottoming tap,

which is the same diameter its entire length.

109. Use of Taps.-Taps are held in tap wrenches while they are being used.

There are two types of wrenches, the T-handlefor small taps and restricted

spaces, and the adjustabletap wrench for general use and larger taps. Examples

of tap wrenches are shown in Fig. 91.

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FIG. 91. TAP WRENCHES.

When starting to tap a hole, secure the work in a vise, if possible. The best

arrangement is one in which the tap can be operated in the vertical position. It is

also very important to start the tap straight and keep it so throughout the work,

because taps, especially small ones, will break if bent or strained. After a tap

starts to cut, it is not fed into the hole with much pressure, as its threads will

tend to pull it in at the proper rate. Also, a tap should not be turned

continuously. The best method is to turn it forward about 1/4 turn, and then

turn it back until the chips break loose, before continuing to turn it forward. Thisprocess should be repeated for each 1/4 turn forward.

Taps work better if they are kept cool. When tapping steel or bronze, the tap

should be well lubricated, preferably with lard oil. The oil also helps the chips to

flow out of the hole and from the flutes of the tap.

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Cast iron is drilled, tapped, and reamed dry. Soft metals, such as brass, can also

be tapped dry.

It should be noted that some small taps, up to the 3/8-inch size, have large

shanks which should not be turned beyond the surface of the work being

tapped, as these shanks exert a reaming action which would cut out the threads.

110. Removal of Broken Tap.-Taps will sometimes break off, even when used

with care. There are two ways of satisfactorily removing the broken part of a tap

from a hole: (1) by means of a tap extractor; (2) by using a chisel or punch.

A tap extractor having 4 "fingers" that slip along the flutes of the tap is shown in

Fig. 92. This tool is turned with a wrench, which must be used carefully to


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prevent damage to the long thin fingers of the extractor.

FIG. 92. USE OF TAP EXTRACTOR.

Broken taps can often be removed by using a blunt cold chisel or a taper punch,

as shown in Fig. 93. If done carefully, this will frequently start the tap. The job

can then be completed with a tap extractor as previously described. Taps often

shatter when they break; the broken pieces should be picked from the hole with

a small prick punch or a magnetized scriber before any attempt is made to

remove the tap. Removing a broken tap by any method is often a long, tediousjob which requires time, skill, and patience. It is therefore wise to avoid

breakage by being as careful as possible.

111. Cutting Outside Threads.-Outside threads are usually cut by the use of

some type of die held in a die stock for turning leverage. The complete assembly

of a stock and solid die is shown in Fig. 94. Solid dies are not adjustable.

Round dies similar to the one shown in Fig. 94, but with an adjustable slot, are

usually found aboard ship. By adjusting the

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FIG. 93. REMOVING BROKEN TAP WITH PUNCH.

width of the split or slot, the diameter and fit of the thread can be controlled.

Some of the dies are equipped with guides, which help to start the cut and keep

the threads straight.

Dies for larger diameters are made in two parts, and are removable,

replaceable, and adjustable. The two parts slide in a groove and are adjusted

with a screw. Two types of adjustable dies are shown in Fig. 95.

The procedure for using dies correctly is similar to that for


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FIG. 94. STOCK AND DIE.

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FIG. 95. ADJUSTABLE DIES.

tapping. The work should be held firmly in a vise, and any burr on the end of thepiece to be threaded should be removed. The die will start the cut more readily

if the end of the piece of material is chamfered slightly to provide a starting

place for the die. The chamfer can be cut with a file or a grinder. To start the

thread, place the large side of the opening in the die over the work and press

down firmly on the stock. Die threads are tapered from one face only, so be sure

to start the cut with that face. Reverse the die only when it is necessary to cut

full threads up to a square shoulder. When cutting the thread, turn the die

forward for part of a revolution and then turn it back slightly so as to release the

chips before making the next forward turn.

It is usually best to adjust the die to cut oversize threads at first, as threads can

always be made smaller, but cannot be made larger. Examine the finished

threads for imperfections. Each thread should be a full thread.

112. Pipe Fittings.-Aboard ship it is often necessary to cut, thread, bend and fit

together various lengths of pipes. It is therefore important to be thoroughly

familiar with the commonly used fittings, examples of which are shown in Fig.

96.

Pipes up to 2 inches in diameter are usually joined with pipe fittings. The pipe

fittings are tapped and threaded with pipe threads, which taper 3/4 inch per foot

of thread. Larger pipe is usually joined either by bolted flanges or by welding.


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Additional information concerning pipe fittings will be found in Marine

Pipe-fitting.

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FIG. 96. PIPE FITTINGS.

113. Cutting Pipe.-Pipe can be cut with a hacksaw, but a pipe cutter is more

satisfactory and should be used, if available. The use of a pipe cutter and pipe

vise is shown in Fig. 97. The cutter has a special alloy steel cutting wheel and two

pressure rollers.

When measuring pipe it is necessary to allow sufficient length for thread to

enter each fitting. The amount to be allowed for the thread depends on the

nominal diameter, or size, of the pipe,

FIG. 97. PIPE CUTTER AND PIPE VISE.

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TABLE II.

Pipe Diameter, Inches

Nominal

Diameter and

MarkedSize of Tap

Actual

Outside

Actual

Inside

Threads

per

Inch

Size of

Tap Drill

(Reamernot used)

Length

Allowed

for Thread,Each Fitting

Inches

1/8 0.405 0.269 27 R 5/16

1/4 0.540 0.364 18 7/16 7/16

3/8 0.675 0.493 18 37/64 7/16

1/2 0.840 0.622 14 23/32 9/16

3/4 1.050 0.824 14 59/64 9/16

1 1.315 1.049 11 1/2 1 5/32 11/16

1 1/4 1.660 1.380 11 1/2 1 1/2 11/16

1 1/2 1.900 1.610 11 1/2 1 47/64 11/16

2 2.375 2.067 11 1/2 2 7/32 3/4

2 1/2 2.875 2.469 8 2 41/64 1 1/16

3 3.500 3.068 8 3 1/4 1 1/8

3 1/2 4.000 3.548 8 3 3/4 1 3/16

4 4.500 4.026 8 4 1/4 1 3/16

5 5.563 5.047 8 5 5/16 1 5/16

6 6.625 6.065 8 6 23/64

and is given in Table II. When the correct measurement has been determined,

the location of the cut should be marked clearly on the pipe with a file or scriber.

The pipe should be secured firmly in the pipe vise, as shown in Fig. 97, and the

cutter slipped over the end. Set the cutter with the cutting wheel on the mark

previously made, and then rotate the cutter around the pipe, gradually taking up

on the cutting wheel, by turning the handle of the cutter, until the pipe is cut

through. In order to keep the wheel tracking properly, the cutter must be kept

perpendicular to the work at all times.

The operation of the pipe cutter leaves a shoulder on the outside of the end of

the pipe and a burr on the inside. Always remove both. If the burr on the inside

is not removed, the ragged edges will catch dirt and other solid matter and will

block the flow. A pipe reamer, Fig. 98, is used for the purpose.

114. Threading Pipe.-Special dies, called pipe dies, are used to

cut pipe threads. As with bolt and screw threads, most pipe threads are cut for

right-hand turning, but left-hand pipe dies are available, as some installations

require a left-hand thread.

Most pipe dies can be adjusted to cut slightly different depths of threads. When

an adjustable die is used, the thread is cut to about 1/2 depth at first, then the

die is readjusted to finish cutting the thread to the full depth.

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FIG. 98. PIPE REAMER.

To cut a pipe thread, secure the pipe in a pipe vise, and place the stock and die

on it as indicated in Fig. 99, This type of die has a guide clamp, as shown in the

illustration. The clamp fits over the pipe and is tightened in position with a

screw. As the die stock is revolved, the clamp draws the die on the pipe, the die

cutting the thread as it is turned. The clamp also helps to keep the threads

straight.

The number of threads cut should not be greater than the number of threads of

the die, and the cut is complete when the end of the pipe is flush with the back

surface of the die. The work should be backed up frequently as with the other

forms of thread cutting, so as to clear the chips. Oil should be used freely during

the thread cutting process.

115. Pipe Wrenches.-Threaded joints should be screwed together by hand and

then tightened with a pipe wrench, often

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works only in one direction, as shown in Fig. 101. The pipe wrench will be found

to function best when the bite is taken midway of the jaw teeth, and when the

size of the wrench is properly chosen for the job. Jaw teeth should be kept clean

and sharp, and the springs should be kept in good operating condition to allow

quick one-hand grip and release. A few drops of oil applied to the adjusting nut

will help to keep the wrench in good working order.

Pipe wrenches are made in sizes ranging from 6 to 48 inches. The correct

wrench sizes for use with various sizes of pipe are given in the following:

Pipe Wrench Size (inches) Pipe Size (inches)

6 1/4

10 3/8 and 1/2

14 3/4

18 1 and 1 1/4

24 1 1/2 and 2

36 and 48 2 1/2 and up

116. Chain Pipe Wrenches.-Chain pipe wrenches, also known as "chain tongs,"

are wrenches of the chain strap and lever type. Two examples of this wrench are

shown in Fig. 102. They are generally designed for use on large diameter piping,

although they are also made in sizes suitable for handling small pipe.

When using this type of wrench, the best gripping position is midway on the jaw

teeth. The wrench is also designed so that the handle will bend under a heavyload before the chain will break. The bending of the handle should therefore be

taken as a warning that maximum load has been applied.

110

FIG. 102. CHAIN PIPE WRENCHES.

On the type of wrenches that have flat link chains, an occasional inspection

should be made of the first two or three rivets and links adjacent to the anchor

link, as the load is greatest at that point. Badly bowed or curved rivets indicate

that the chain has been loaded almost to breaking strength and is probably

unsafe. On cable-link chains the links give warning by stretching and pulling

"rigid" if the breaking point is approached.

117. Rivets.-Rivets, although not threaded, are classified as metal fasteners, the

pressure of their heads, instead of threads, exerting the holding force. Rivets are

commonly used for permanent fastening and are not practical for any assembly

that has to be taken apart. Rivet holes must be drilled or punched and must be


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carefully spaced and aligned. The thickness of the parts to be riveted and the

load to be applied determine the proper diameter and length of the hole.

Tinner's rivetsare used on thin metal sheets. They have flat heads, are made of

soft iron or steel, and are usually coated with tin as a protection against

corrosion. The weight, in lbs, of 1,000 rivets, denotes the size of rivets, as shown

in Fig. 103. The length of a rivet is proportional to its weight and diameter.

The use of a rivet setis necessary with tinner's rivets. After the rivet has been

inserted in the holes in the pieces of material being riveted together, the set is

placed over the headless end of the rivet and is used to press the sheets of

metal together and against the rivet head. The recessed hole for this purpose in

the set is indicated by the broken lines in Fig. 103. The set is then removed

111

FIG. 103. TINNER'S RIVETS AND RIVET SET.

and the rivet is upset (headed upon the headless end) with a riveting hammer.

After this is done, the set is used to round the upset end. Rivet sets are provided

in several sizes.

Structural rivets, shown in Fig. 104, may be used to fasten the plates of a tank or

boiler and the structural members of a ship. They are used on many types of

steel frameworks and structures, and are usually heated for driving. This causes

the rivets to contract as they cool and helps to hold the riveted members tightly

together. The rivets also drive easier when hot. Structural rivet diameters vary

from 1/4 inch to 1 1/4 inches, but even larger sizes are used for thick sections.

The length of a rivet should be approximately 1 1/2 times the diameter of the

rivet, plus the grip (combined thickness of the riveted sheets).

The terms used in Fig. 104 should be noted. The landing, or distance from the

center of the rivet to the edge of the material, should not be less than times the

diameter of the rivet. The space between rivets should be from 3 to 8 diameters

of the rivet used, measured from center-to-center.

While one end of a rivet is being hammered, the other end must be supported

by an anvil or some other suitable means. The force of the blow should always

be proportioned to suit the size of the rivet.


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A rivet may be removed by cutting off the rivet head with a

112

FIG. 104. STRUCTURAL RIVETS.

cold chisel and punching out the body of the rivet. In case of a large rivet, first

cut a groove through the center of the rivet head, as shown in Fig. 105 (A). Then

cut off the rivet head as shown in view (B). A small rivet is easy to remove if the

head is drilled before the chisel is used. The hole should be drilled through the

head only, and the weakened head then cut off with a chisel.

FIG. 105. CUTTING OFF RIVET.

118. Reamers.-A very slight variation in the nominal diameter of a drilled hole is

of little importance in some cases, but where greater accuracy is required, the

holes are reamed, that is, the hole is first drilled somewhat smaller than the

exact desired diameter, and is then reamed out to the proper size with a

reamer. The principal reason for the reamer being able to do better work than

the drill is that it is not used to originate holes, and its action is, therefore, not

dependent upon a somewhat uncertain guiding point. Other reasons are that it

nearly always has more than

113

two cutting edges, and when properly used should have very little metal to

remove.

Reamers are made either of carbon tool steel or high-speed steel. The cutting

blades of a high-speed steel reamer lose their original keenness sooner than


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those of a carbon steel reamer. However, after the first super-keenness is gone,

the reamer is still serviceable, and the high-speed tool will last much longer than

the carbon steel type.

The two types of hand reamers in general use are straightand taperreamers.

Four types of straight reamers are shown in Fig. 106. The solid reameris one

solid piece throughout. The expansion reameris hollow and has longitudinal cutsin some of its flutes. By means of a tapered screw plug its diameter can be

expanded

FIG. 106. TYPES OF STRAIGHT REAMERS.

a few thousandths of an inch. Both solid and expansion reamers are made with

straight and spiral flutes, and the cutting edges or lands between the flutes are

usually regularly spaced. However, some solid reamers have irregularly spaced

lands to avoid "chatter," which causes roughness in the finish of the work.

The blades of the adjustable reamerare separate from the body and are fitted

into grooves in the threaded shank of the tool. Adjusting nuts fit on thesethreads, and when the nuts are turned back and forth, the blades are moved

along the tapered grooves,

114

thus increasing or decreasing the diameter of the reamer. It is advisable to use a

solid reamer for most work because it is the most rugged and accurate of the

straight reamers.

119. Use of Reamer.-Reamer blades are hardened to such an extent that they

are brittle, so reamers should be handled carefully to prevent chipping the

blades.Always rotate a reamer in the cutting direction.

Another important factor in the use of a straight hand reamer is to have the

hole the correct size to begin with, and then to be sure that the reamer is

started straight in the hole. One method of getting the reamer started straight,

by checking it from side to side with a square, is shown in Fig. 107.

Straight reamers have a slight taper on 1/4 to 3/4 inch of the end, so that they

will start into the hole easily. One form of reamer has a shallow screw thread at

the entering end. This thread takes hold of the metal and draws down into the


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work.

FIG. 107. USING SQUARE TO START REAMER STRAIGHT.

115

A reamer is turned by means of a wrench, or it can be set up in a vise and the

work turned around it. The reamer should be turned slowly until the operator is

sure that it is straight in the hole, and then should be turned with a steady, firm

pressure until it has been put all the way through the hole. The leading end is

subjected to the greatest amount of wear because it does the greatest amount

of work. If, therefore, only this leading end is put through, the hole will not be ofa uniform diameter throughout.

120. Taper Reamers.-Taper reamers are used to finish tapered holes for the

insertion of tapered pins or other tapered parts. A solid taper reamer and taper

pin are shown in Fig. 108.

FIG. 108. TAPER REAMER AND PIN.

Taper reamers are made with a standard taper of 1/4 inch per foot, the various

sizes being arranged so that each overlaps the next size by about 1/2 inch, that

is, a No. 8 taper reamer could be inserted about 1/2 inch into a hole that hadbeen reamed with a No. 7 reamer.

When using taper reamers, it is very important that the drilled hole be the right


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size, generally just large enough to allow about 1/2 inch of the reamer's length

to enter it. A table similar to Table III should be consulted for the correct size of

drill and other pertinent dimensions. However, if such a table is not available, no

choice remains except the "cut and try" method, taking extreme care not to

ream the hole too large or too deep. When starting the taper reamer, always

keep it as straight as possible.

121. Machine Reamers.-The machine reamer is usually inserted in a chuck or a

socket mounted in the spindle of a portable electric

116

or air motor. Machine reamers are also made either solid or adjustable, and

each of these groups may be subdivided into straight or taper reamers.

Machine reamers differ from hand reamers in that nearly all the cutting is done

by the beveled ends of the teeth, which act as a series of single cutting tools,

each taking a small part of the total cut. The hand reamer is constructed so that

all of its cutting is done by the sides of the teeth. Machine reamers are often

used where holes are to be finished to a fair degree of accuracy and with a fair

finish, but when extreme accuracy and a fine finish is required, hand reamers

are used.

For general use, an expansion type of machine reamer is the most practical. This

type is furnished in standard sizes from 1/4 inch to 1 inch, increasing indiameter by 32nds. Each reamer has a maximum expansion of 1/32 inch, so a

set covers any reaming job from 1/4 to 1 inch.

Internal hones are much like adjustable reamers. The principal difference is that

hones have abrasive blades. Large hones are rotated by electric drills or special

motors for such jobs as truing the walls of engine cylinders.

122. Care of Reamers.-As stated previously, a reamer must never be turned in

any way except to the right, or clockwise, even when removing it from the work.

Do not use too much feed (pressure) because the reamer may hit a hard spot inthe metal and break. This is especially likely with small reamers. When using a

lubricant on the reamer, it is good practice to remove the tool from the work

frequently and wipe away the chips which stick to the flutes. If the chips should

clog, they would be likely to damage the finish on the walls of the hole.

Remember that an adjustable reamer must be kept absolutely clean to do

accurate work. Handle reamers carefully; if they are dropped or thrown against

other tools, their sharp edges will be nicked and dulled. If the hole is too small,

enlarge it with a drill before reaming it.

123. Preventing Chatter in Reamers.-When a hand reamer chatters, even

when fed with the proper pressure, it is generally a sign that it has not been

sharpened correctly for the particular metal being reamed. When chattering

occurs, replace the reamer being used with another one. If it is not replaced, the

walls of the hole will be rough, and work and time will be wasted.

117

TABLE III.

Taper Reamers and Pins


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Size

No.

Dia. of

Small

End of

Reamer

(Inches)

Dia. of

Large

End of

Reamer

(Inches)

Length

of

Flute

(Inches)

Total

Length

of

Reamer

(Inches)

Size

Drill

for

Reamer

(Inches)

Longest

Limit

Length

of Pin

(Inches)

Dia. of

Large

End of

Pin

(Inches)

Approx.

Fractional

Size at

Large End

of Pin

(inches)

0 0.135 0.162 1 5/16 2 28 1 0.156 5/32

1 0.146 0.179 1 9/16 2 3/8 25 1 1/4 0.172 11/64

2 0.162 0.200 1 13/16 2 11/16 19 1 1/2 0.193 3/16

3 0.183 0.226 2 1/16 3 12 1 3/4 0.219 7/32

4 0.208 0.257 2 3/8 3 7/16 3 2 0.250 1/4

5 0.240 0.300 2 7/8 4 1/8 1/4 2 1/4 0.289 19/64

6 0.279 0.354 3 5/8 5 9/32 3 1/4 0.341 11/32

7 0.331 0.423 4 7/16 6 1/16 11/32 3 3/4 0.409 13/32

8 0.398 0.507 5 1/4 7 1/16 13/32 4 1/2 0.492 1/2

9 0.492 0.609 6 1/8 8 1/8 31/64 5 1/4 0.591 19/32

10 0.581 0.727 7 9 1/2 19/32 6 0.706 23/32

11 0.706 0.878 8 1/4 11 1/4 23/32 7 1/4 0.857 55/64

12 0.842 1.050 10 13 3/8 55/64 8 3/4 1.013 1 1/64

13 1.009 1.259 12 16 1 1/64 10 3/4 1.233 1 15/64

Taper equals 1/4 inch per foot or 0.0208 inch per inch.

These reamer sizes are so proportioned that each overlaps the size smaller

about 1/2 inch.

118

Resharpening reamers is usually a factory operation; the average person shouldnot attempt it, although sometimes, if the edges of the reamer are only slightly

dull, they can be restored by using a fine stone on the flutes. If the reamer is

adjustable, it may be possible to insert new blades in it.

124. Scrapers.-Scrapers are made in many forms, the type to be used

depending on the particular job to be done. Several commonly used types are

shown in Fig. 109. Flat scrapersshould be used for scraping or removing high

spots from flat surfaces only; bearing scrapers are used for truing up bearing

surfaces; and the 3-corner scraperis commonly used for removing burrs or

sharp internal edges from soft bushings, etc.


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Each bearing half is also tested by applying a thin coating of Prussian blue to the

shaft and then placing a bearing half on the shaft and rotating it back and forth

several times. When the bearing is removed from the shaft, the spots of blue on

the bearing metal indicate the areas of contact. These high spots are removed

by the process known as "scraping in," which means that a bearing scraper is

used to scrape off the contacting areas, the bearing being retested and scrapedin until uniform distribution of the blue spots indicates that the bearing bears

evenly over the desired surface.

Since the scraping of a bearing usually involves the removal of a comparatively

small quantity of soft bearing metal, and the cutting edges of the scraper are

ground to a keen edge, only a light scraping pressure is needed. If too much

pressure is applied, not only will too much metal be removed, but in addition

the scraper will tend to "chatter" and leave a rough uneven surface.

When scraping a bearing, the handle of the scraper is held firmly with one hand

and the blade of the scraper carefully guided

120

with the other hand. The scraper can be pushed away or pulled toward the

workman, depending on the location of the high spot, the position in which the

bearing is held, or where the workman is standing in relation to the bearing.

When scraping, however, always scrape in a crosswise direction, following thecurve of the metal. Do not scrape lengthwise. Also be careful not to gouge or

chip excess metal when scraping at the edges of oil grooves or other openings.

In general, as explained previously, it is best to remove only a small amount of

metal and then recheck the location of the high spots before continuing with the

scraping. The work is usually not considered complete until the blue spots are

distributed over a combined area equivalent to about 75 per cent of the total

bearing surface.

Remember that scraping increases the running clearance of the bearing. If toomuch metal is removed, the clearance will be increased above the desired

amount and this will necessitate the removal of shims to reduce the clearance.

Removal of shims might possibly create a new series of high spots and the

fitting and scraping would have to be done all over again.

127. 3-Corner Scrapers.-When using a 3-corner scraper, use the same motion

as though .handling a bearing scraper. As a rule, the 3-corner scraper is used on

material requiring fairly firm pressure, but only a small amount of metal should

be removed at each stroke.

FIG. 111. CARBON SCRAPER.

128. Carbon Scrapers.-The carbon scraper, Fig. 111, is a tool commonly used

for cleaning carbon deposits from cylinder heads, pistons, and chambers of

small engines. This scraper has a dull edge to lessen the danger of scoring the

piston or cylinder wall.

129. Care of Scrapers.-Keep scrapers (except the carbon scraper) sharp at all


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times, or they will not leave a smooth surface and will require more pressure

than is necessary. The usual method

121

of sharpening is first to grind the tool on a wheel, and then to finish the

operation on an oilstone. In scraping any surface, apply the pressure to the

scraper on the cutting stroke only, otherwise the tool will soon become dull.

When using scrapers observe the following precautions:

(1) Keep the hands free from grease, oil, or perspiration.

(2) Keep the hands high enough from the work to avoid striking a

corner of it while working; these corners are often sharp and can give

the hand a disagreeable and perhaps dangerous cut. Be especially

careful of the bearing scraper; its edges are very sharp.

FIG. 112. GASKET CUTTER, FLY CUTTER, AND HOLE SAW.

130. Gasket Cutters.-A gasket cutter, Fig. 112, is used to cut round gaskets from

sheets of gasket material, such as cork, rubber, leather, asbestos, composition,

etc. The tool has two adjustable knives; one makes the inside hole, the other

cuts the outside of the gasket. The sizes of the gaskets are therefore limited only

by the size of the cutter available. When cutting a gasket, the material is spreadout on a piece of wood, the outside and inside diameters of the gasket are

determined, and the knives are adjusted at the correct position. With the shank

of the tool held in a brace, the

122

pivot point is inserted through the gasket into the wood and the cutter rotated

carefully until the knives cut through the gasket material.

To make bolt or stud holes in the gasket after it has been cut, mark their

location accurately on the gasket, and then use a gasket punch to cut the holes.


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The preparation of a gasket, especially for an irregularly shaped surface, can

often be facilitated by holding the gasket material in place on the joint area and

carefully tapping the outline of all openings with the ball peen of a machinist's

hammer. If this is done skillfully, the edges of the stud holes and other

apertures will cut the gasket to fit as the peening is carried out. Best results can

usually be achieved by this method when the piece of material from which thegasket is made is only slightly larger than the joint. A larger piece of material

might be bulky and inconvenient and tend to slip while being worked on, thus

ruining the job. Try to use the gasket material, however, so that there is little

waste.

131. Fly Cutters.-Fly cutters, Fig. 112, are designed to cut holes in sheets of soft

metal, such as brass, aluminum, soft steel, etc. They may also be used to cut

holes in sheets of fiber, bakelite, plastic, and similar materials. One type of fly

cutter has one cutting bar and the other has two cutting bars. The tool is used inmuch the same way as a gasket cutter.

132. Hole Saws.-For making large round holes in wood or metal, a set of hole

saws is useful. These tools, one of which is shown in Fig. 112, are not adjustable,

but are made in all common sizes. They are also available in two types, a

coarse-tooth saw for cutting wood, cast iron, bakelite, and other thick, coarse

material, and a fine-tooth saw for cutting sheet metal, steel, porcelain and other

fine, thin material. They can be used in a hand or electric drill.

133. Forging Tools.-Some vises have a small anvil, as explained previously, but alarger anvil is also a very handy piece of equipment to have aboard ship. The

face or main working surface of the typical anvil shown in Fig. 113 is made of

tough steel. A square hole extends through the anvil top to hold the hardie,

which is used for cutting metal bars and rods. The metal to be cut is placed

123

FIG. 113. ANVIL. AND HARDIE.

over the hardie and struck with a hammer or sledge. The end of the anvil

opposite the hardie hole has a pointed or cone-shaped horn, over which curved

portions of bars and rods may be formed.

The top surface of the anvil should be treated with care so as to avoid dents and

scratches. Its primary purpose is to provide a working surface that will support

the metal while it is being pounded into shape. This surface forms or shapes

part of the object being forged, so the smoother it is, the better the job. It is

therefore not advisable to use a chisel, for example, to cut metal on the anvil,

unless the surface is protected against injury.


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Sledgesare used for heavy forging. Swagesare used in matching pairs to shape

round or oval objects. Fullersare used to shape round inside corners and inside

angles. The set hammerand theflatterare used to smooth and finish flat

surfaces. These tools are shown in Fig. 114.

Tongsare used for handling hot pieces of metal. Their jaws differ according touse, otherwise the many varieties are much alike.

The hot chiselis really a special hammer with a chisel edge. It is used only when

hot metal is to be cut. To use it, place the metal on the anvil, set the hot chisel

cutting edge in place, and strike the other end of the head with a hammer or

maul. If the cut is to be completely through the piece of stock, place a piece of

scrap metal under the work to prevent damage to the anvil. The cold chiselis

heavier and stronger than the hot chisel. It also has a handle so that it can be

held in place while it is pounded on.

Punchesare used to punch holes in hot metal. In addition to the round punch

shown in Fig. 115, there are also square,

124

FIG. 114. FORGING HAMMERS.

rectangular, half-round and oval punches. They too are used only on hot metal.

134. Hoists.-Quite frequently it is necessary to lift various parts of an engine orother piece of equipment, and in some cases a complete unit must be lifted.

There are many devices employed to do heavy lifting, but one of the most

common is the hoist, generally known as a "chain falls." Of the several types of

hoists, the


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33/51

136. Spur-Geared Chain Hoist.-The hoist shown in Fig. 117 is of the

spur-geared reduction type. This unit may be constructed with either single or

double chain, and is a fast, powerful and durable mechanism. It can handle

loads up to 40 tons, depending upon its construction.

126

FIG. 117. SPUR-GEARED CHAIN HOIST.

1. top hook

2. brake dust guard

3. crosshead

4. suspension plates5. automatic load brake

6. load sheave

7. driving pinion

8. ball bearings

9. load chain

10. gear system

11. hand chain guide

12. thrust bearing

13. hand chain

14. load hook

Heavy suspension plates connect the top hook crosshead and the load sheave

of the spur-geared hoist. These plates also directly support the saddle used in

the double-chain arrangement, eliminating the need for a top yoke, and

reducing weight and headroom.

The load sheave is mounted on ball bearings which are enclosed to protect

them from grit and dust. The automatic load brake, which holds the load in anyposition, is also protected by a dust guard. A continuous pull on the hand chain

is required to lower the load.

137. Screw-Geared Chain Hoist.-Where the higher speed of a spur-geared hoist

is not required, the screw-geared hoist, Fig. 118, is recommended. It is well

adapted for portable use, and though light, is powerful and durable. It holds the

load securely, and will not lower except as the hand chain is pulled. This is an

excellent hoist for temporary and occasional service, as it may be moved readily

to meet an emergency. It is also adaptable for horizontal work. The worm gear

makes this hoist compact for lifting loads in cramped places and close up to the

overhead.

The screw-geared hoist is operated on the worm wheel and screw principle. The

hand chain drives a sprocket wheel directly keyed to the worm shaft. The worm

meshes in the worm wheel, which in turn drives the shaft holding the two load

sheaves.

The hoist is operated by a comparatively light chain pull. With

127


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FIG. 118. SCREW-GEARED CHAIN HOIST.

a 1-ton hoist, for example, one man with an approximate pull of 87 pounds can

lift 2,000 pounds. However, the relatively large overhaul of hand chain required

to lift the load makes it proportionately slow in operation. The capacity of this

type of hoist ranges from 1/2 ton to 5 tons.

138. Ratchet Lever Hoist.-The ratchet lever hoist, Fig. 119, is designed to

function as a general purpose tool for pulling and hoisting, having the

characteristics of light weight and minimum distance between hooks. It also has

self-actuated load brakes, a ratchet or universal action to permit use in

congested quarters, and is compact and efficient.

The ratchet lever hoist operates by means of a ratchet, which actuates a lifting

sprocket. The ratchet action permits short strokes on the handle with the load

supported on the brake at any point of the lifting action. When lowering the

load, the handle is operated in the same way as when lifting. The change from

hoisting

128


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FIG. 119. RATCHET LEVER HOISTS.

to lowering is easily accomplished and controlled by a small thumb turn on the

handle.

The capacity of the ratchet lever hoist is from 3/4 ton to 6 tons, depending upon

the number of chains. In Fig. 119, for example, the 1-chain hoist has a capacity

of 3/4 ton to 1 1/2 tons; the 2-chain hoist, 3 tons; and the 4-chain hoist, 6 tons.

139. Whatever the type of hoisting device used, care must be taken to safeguard

the operator and other personnel working on or near the hoisting operation,

and for this reason the following precautions should be observed :

1. Be sure that the lifting gear is heavy enough to carry the load.

2. Be sure that none of the links in the chains are twisted.

3. Be sure that the hitch is made in the correct manner, so that nothing can slip

when the load is picked up.

4. Do not start the lift until everything is clear.

5. Keep all personnel clear of the piece being lifted, so that if anything should

slip or break no one will be injured.

129

6. Keep all personnel out from under the piece that is being lifted.

7. When the load might swing, as would occur at sea, be sure to have suitable

stay lines to hold the piece in position.

8. After a lift has been made, it is not good practice to leave the load hanging onthe hoist without some other support. Blocking should be used to assume most

of the load, thus keeping only a moderate strain on the hoist.


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9. When a piece of machinery has been lifted and moved to another position,

always make sure to set it down on a secure foundation. It is often advisable to

lash it down securely to prevent accidental movement.

140. Tube Expanders.-It is often necessary aboard ship to expand or "roll in"

tubes in boilers, condensers, coolers, etc., a process that involves the use of atube expander. A typical tube expander for use on the generating tubes of a

boiler is shown disassembled in Fig. 120. An expander that would be used for

rolling and belling

a. expander cage

b. straight and belling rolls

c. mandrels, various diameters

FIG. 120. EXPANDER FOR BOILER GENERATING TUBES.

both ends of the short nipples that connect the headers to the drums in some

boilers, is shown in Fig. 121.

As shown in the illustration, a tube expander consists of a cage containing the

rolls, a slightly tapered mandrel which expands the rolls, and a wrench for

turning the expander. Both straight and belling rolls are used in the expanders

shown in Figs. 120 and 121, making it possible to expand and bell a tube in one

operation.

130

a. expander cage e. driving link, short

b. belling rolls f. universal joint


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c. mandrels, various diameters g. driving link, long

d. coupling h. ratchet wrench

i. straight rolls

FIG. 121. BOILER TUBE EXPANDER FOR FORWARD AND REVERSE ROLLING.

It is necessary to have an expander for each tube diameter. Three different sizesof expanders as used in a boiler are shown in Fig. 122; a small expander that

would be used on condenser tubes is shown in Fig. 123; and expanders in

position for rolling and belling both ends of a mud-drum nipple are shown in

Fig. 124.

141. Use of Tube Expander.-To expand a tube, place the expander in the tube

so that the rolls bear on the portion of the tube which is in the tube sheet. The

mandrel should be inserted just far enough to press the rolls firmly against the

tube and hold the expander in place. A wrench is then applied to the expander

mandrel and the expander is turned clockwise. The progress of the rolling must

be watched carefully, and rolling stopped when the tube is expanded enough to

obtain a tight joint. Particular attention should be paid to the action of the

belling rolls, when fitted, for if the expander is started too far in the tube it will

make too large a bell before the tube is tightened. When belling rolls are being

used and it is observed that the tube has sufficient bell,

131


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FIG. 122. BOILER TUBE EXPANDERS.

the rolling should be stopped. If the tube is not expanded tightly in the tubesheet, the expander should be backed out slightly before the rolling is

completed, thus avoiding over-belling. If the tube tightens in the seat first and

does not have sufficient bell, move the mandrel outward slightly, set the

expander farther into the tube, and continue the rolling as previously explained.

Tubes should be expanded just enough to obtain a tight joint that will not leak

when a hydrostatic test is applied. Excessive rolling will cause a reduction of the

tube wall thickness and

132

FIG. 123. CONDENSER TUBE EXPANDER.

produce weak joints. It also tends to enlarge the tube holes, making it difficult to

maintain tight joints. If a tube hole should be excessively enlarged, a ferrule

might have to be installed in the tube sheet to return the hole to normal size.

When using an expander, the rolls and mandrel should be well lubricated with


39/51

fairly heavy lubricating oil. After each use, clean the expander and lubricate it

again, if necessary, before rolling the next tube. Maintain the rolls in good

condition and do not attempt to use chipped or cracked rolls. Always clean and

oil the expander when storing it for future use.

FIG. 124. EXPANDING AND BELLING MUD-DRUM NIPPLES.

142. Coupling and Gear Puller.-A 3-jaw puller, suitable for removing couplings,

gears, etc., from shafts, is shown in Fig. 125. This tool is designed to exert a

strong, uniform pull, and is arranged for convenient use. Spring tension helps to

hold the jaws

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hammer or a hammer and a piece of wood. Be sure to tap at the hub of the

coupling or gear, and not at the circumference. Tap evenly all around the hub,

so that the work will not become cocked and jammed on the shaft.

Before starting to remove a coupling or gear from a shaft, it is advisable to

examine for nicks and burrs that section of shaft over which the part must slide,

removing such imperfections as may be observed. In some cases a film of oil orgrease or a thin coating of white lead applied ahead of the work will facilitate its

removal. If the part has rusted to the shaft, the use of penetrating oil may be

needed to break up the corrosion.

A special circular plate is provided with the tool shown in Fig. 125 so that the

puller may be used on a fiber gear or similar part, where pulling directly on the

material might cause damage. The plate can be attached by the cap screws to

the part to be removed, and the puller is then applied to the plate.

It should be noted that the jaws of the puller are reversible, permitting their use

through an opening for inside pulls on bushings, sleeves, etc. When used in this

way, a piece of stock of sufficient length for the stud to bear against would have

to be placed in the opening. The yoke of the puller is also made with 2 sets of

jaw slots, allowing the jaws to be moved closer to the center for better gripping

power on small jobs.

If a suitable puller is not available, it is possible to make a satisfactory tool from

material available aboard ship, the material to be used depending in part on the

job to be done. For extra heavy work the puller would have to be made fromheavier and stronger stock.

A puller such as shown in Fig. 126 can be made from scrap metal and will

accomplish the work adequately. Remember that the center piece must be wide

and heavy enough to allow a hole to be

135

drilled and threaded. To make the stud, a piece of stock of suitable length isthreaded, and then one end squared so that a wrench will fit on it. The two jaws

should be cut from heavy enough material so that they will not bend when the

force is applied. The adjusting holes may be cut as desired.

FIG. 126. HEAVY-DUTY PULLER.


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FIG. 128. SODA-ACID EXTINGUISHER.

before recharging. The extinguishers should be examined at regular intervals to

make sure that they have not been tampered with or removed from their

designated places. They should also be inspected to see that they are properly

filled and that the orifice of the hose is not clogged. In addition, at least once

yearly when emptying and recharging, all parts of the extinguishers, including

the gasket and hose, should be examined carefully for deterioration or injury.

Extinguishers or parts which are not in good condition should be replaced.

Recharging of extinguishers should always be done under capable supervision,

and the date of recharging and signature of the person who performed it should

be entered on the tag attached to the extinguisher. It is also important that acid

bottles and their corresponding stoppers, when replaced, should be exact

duplicates of those originally provided, as otherwise the discharge may be

impaired or the extinguisher rendered inoperative.

When preparing the soda solution, the powdered chemical should be

thoroughly dissolved in water outside the extinguisher in accordance with

instructions on the extinguisher or as provided by the manufacturer of thechemical. The water should be lukewarm but never hot. A quantity of chemical

charges supplied for use in the extinguishers must be kept on hand so that each

unit may be recharged promptly after each use.

In localities where continued temperatures lower than 40F

139

may prevail, soda-acid extinguishers must be situated so as to be protectedagainst freezing. Anti-freeze ingredients such as common salt, calcium chloride,

etc., must not be used in extinguishers of this type, as such substances may

either reduce the effectiveness of the discharge or change its nature, or may

cause corrosion and make the unit dangerous for use. 148. Water or

Anti-Freeze Solution Extinguishers.-Approved hand fire extinguishers

designed to contain either water or an anti-freeze solution are made in two

sizes, with liquid capacity of approximately a gallons and 5 gallons, respectively.

The antifreeze solution is prepared from a calcium chloride base with other

components added to prevent corrosion and deposits on the


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FIG. 129. WATER OR ANTI-FREEZE SOLUTION EXTINGUISHER (PUMP-TYPE).

140

operating parts of the extinguishers. This type of apparatus is effective in the

same cases as the soda-acid extinguisher, that is, Class A fires where water can

be used effectively.

These extinguishers are often pump-operated, as shown in Fig. 129, and can be

discharged intermittently, with the force, length and duration of the stream

being dependent on the operator. It is not feasible, however, to operate this

particular type of extinguisher while carrying it about.

The same general precautions concerning inspection and recharging that arerecommended for soda-acid extinguishers must be enforced, and when located

where low temperatures may be encountered, water-type extinguishers must be

protected from freezing unless charged with the anti-freeze solution. The

operation of the pumps should also be tested by operating them several

strokes, discharging the solution back into the extinguisher. A few drops of light

lubricating oil should be placed on the pump rod packing.

Some water-type extinguishers contain a carbon-dioxide cartridge instead of a

pump. When this extinguisher is inverted, the cartridge is perforated, releasinggas which builds up a pressure in the extinguisher and causes it to discharge. All

cartridges should be removed and examined when cartridge-operated


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extinguishers are inspected, and should be weighed on an accurate scale to

detect loss of pressure by leakage. It is recommended that a new cartridge be

used to replace any which shows a loss of 1/2 ounce or more from the original

weight stamped on it.

When recharging extinguishers with anti-freeze solution, the chemical should be

thoroughly dissolved in water outside the extinguisher, in strict accordance withinstructions provided by the manufacturer of the extinguisher or chemical. The

water should be warm and the solution should be poured through a fine

strainer when placing it in the extinguisher.

Common salt or other unspecified chemicals should not be used in anti-freeze

solution extinguishers, as they may corrode or otherwise be made dangerous

for use. Cartridges other than those furnished by the manufacturer should not

be used in cartridge-operated extinguishers.

149. Foam Extinguishers.-Foam extinguishers are made in sizes up to 5 gallons.

The chemicals used are bicarbonate of soda and a foam stabilizing agent

dissolved in water, for the outer compartment,

141

and aluminum sulphate dissolved in water for the inner cylinder. The

extinguishing agent is a foam which results from the reaction of the two

chemical solutions. A typical foam extinguisher is shown in Fig. 130.

FIG. 130. FOAM EXTINGUISHER.

Foam extinguishers are designed to be carried to the fire by means of the top

handle and must be inverted for use. When the chemicals mix as a result of the

extinguisher being inverted, foam is produced and a pressure created within the

container, causing a stream of foam to be expelled through the hose. This

stream can be directed effectively from a distance as great as 30 to 40 feet

horizontally.

On flammable liquid fires, the best results are obtained when the discharge

from a foam-type extinguisher is played against the wall of the enclosure

containing the liquid, just above the burning surface, so as to permit the natural

spread of the foam over the burning liquid. If this cannot be done, the operatorshould stand far enough away from the fire to allow the foam to fall lightly upon

the burning surface. The stream should never be directed into the burning


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liquid. Where possible, the operator should walk around the fire while directing

the stream, so as to obtain maximum coverage during the discharge period.

For fires in ordinary combustible materials the force of the stream may be used,

or the foam may be used to coat the burning

142

surface, according to the conditions. The use of these extinguishers on fires in

electrical equipment is not recommended.

Foam extinguishers should be recharged annually as well as immediately after

use. When recharging them, all parts should be washed thoroughly with water

and the water drained through the hose. This ensures that the hose and nozzle

are not clogged. Foam extinguishers must also be inspected periodically as

explained previously in connection with other kinds of extinguishers, particular

care again being taken to make sure that the hose and nozzle are clear. If the

discharge of a foam extinguisher should be clogged when an attempt is made to

use it, the pressure can cause an explosion and very possibly injure the person

using the extinguisher.

When recharging foam extinguishers, the chemicals should be thoroughly

dissolved in water outside the extinguisher, in exact accordance with

instructions provided by the manufacturer. Lukewarm water should be used. A

quantity of chemical charges supplied by the manufacturer for use in suchextinguishers should be kept on hand so that recharging may be done promptly

after each use.

Where low temperatures may be expected, foam extinguishers must be located

so as to be protected against freezing. Anti-freeze ingredients such as common

salt, calcium chloride, etc., must not be used.

150. Vaporizing Liquid (Carbon Tetrachloride) Extinguishers.-Carbon

tetrachloride extinguishers are made in several sizes up to a liquid capacity of 3

1/2 gallons. The extinguishing agent used is a non-conducting liquid having acarbon-tetrachloride base combined with other chemicals which depress the

freezing point to 50 below zero and help to avoid corrosion, etc. An

extinguisher of this type is shown in Fig. 131.

When the self-contained pump of this extinguisher is operated, the pumping

action expels a stream of liquid which is vaporized into a gas by the heat of the

fire. In case of a fire in ordinary combustible materials, the stream should be

directed at the base of the flames. On flammable liquid fires, best results are

obtained when the discharge from the extinguisher is played against the insideof the enclosure containing the liquid, just above the burning surface, the same

general procedure being followed as in the use of a foam extinguisher.

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FIG. 131. CARBON TETRACHLORIDE EXTINGUISHER.

Carbon tetrachloride extinguishers are effective on incipient fires in electrical

equipment, where the use of a non-conducting extinguishing agent is essential.

When using these extinguishers, however, especially in confined and poorly

ventilated spaces, precautions should be taken to avoid breathing for extended

periods the vapors or gases liberated, as toxic effects may be experienced.

The extinguishers should be kept filled at all times and should be refilled

immediately after use. They do not need to be protected against freezing, when

charged with the specified liquid. Caution: Do not use water for any purpose in

extinguishers of this type.

At least once yearly, carbon tetrachloride extinguishers must be examined as to

condition of the pump and for deterioration or injury due to misuse. At these

inspections all pumps should be tested by discharging a portion of the liquid

with the stream directed alternately upward and downward. Extinguishers

which are not in good condition should be replaced; others should be refilled by

pouring in enough liquid to replace that which was discharged. The date of

recharging and the signature of the person who performed it should be placed

on the tag attached to each extinguisher.

A quantity of the special fire extinguishing liquid supplied for use in the

extinguishers should always be kept on hand. No liquid other than that

furnished by the extinguisher manufacturers should be used in the

extinguishers, as it might make the extinguisher inoperative or dangerous for

use.

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151. Carbon Dioxide (CO2) Extinguishers.-Carbon dioxide extinguishers, Fig.

132, are made in several principal sizes, ranging from 2 1/2 to 25 pounds of

carbon dioxide. To use this type of extinguisher the valve is opened and the gas

discharged upon the fire through the hose and cone. The discharge has a range

of approximately 8 feet.


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FIG. 132. CARBON DIOXIDE EXTINGUISHER.

The discharge of a carbon dioxide extinguisher should be directed at the base of

the flames in all types of fires, and should be applied to the burned surface evenafter the flames are extinguished. This tends to deposit carbon dioxide snow as

a coating on the hot surfaces and any glowing material, thus reducing the

chances of a reflash.

On flammable liquid fires, best results are obtained when the discharge from

the extinguisher is employed to sweep the flame off the burning surface,

applying the discharge first at the near edge of the fire and gradually

progressing forward, moving the discharge cone very slowly from side to side.

Carbon dioxide extinguishers are effective on fires in electrical

145

equipment, but are not suitable for use on deep-seated fires of wood, paper and

rubbish, as such fires require the quenching effect of water for complete

extinguishment.

When using these extinguishers, the same precautions should be taken to avoid

breathing the liberated gases as are recommended in the case of carbon

tetrachloride.

At least once yearly the extinguishers should be examined as to weight and for

deterioration, as reweighing is the only method of determining whether or not a

carbon dioxide extinguisher is fully charged. They should be weighed on an

accurate scale, and any unit that shows a loss of 10% or more of the rated

capacity stamped on it should be recharged. Unless recharging facilities are

maintained on board ship, it will be necessary to send depleted extinguishers

ashore for recharging. All extinguishers should be refilled as soon as possibleafter use, even though only partly discharged.

Carbon dioxide extinguishers do not need to be protected against freezing.


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approximately 23/32 in.

(a) What size drill should be used?

(b) What size taper reamer should be used?

14. (a) Explain how to test the extent and distribution of bearing area of abearing.

(b) If the bearing area is not uniformly distributed to the proper extent, what

should be done? Explain in detail.

15. Explain how to make a full gasket for a joint on the water end of a pump,

using sheet gasket material. (A full gasket is one that covers all of the joint

surface.)

16. Explain the general precautions that should be taken when using a hoist.

17. Explain how to pull a small gear from a shaft.

18. What precautions should be taken when using a portable electric lamp?

19. If a fire is discovered in a motor in operation, the motor should be shut

down immediately, if possible.

(a) What kinds of fire extinguishers are recommended for use on this type of

fire?

(b) What precautions should be taken when using either of these extinguishers?

20. A ship is expected to pass through a region where low temperatures may be

encountered.

(a) What types of fire extinguishers must be protected against freezing?

(b) How is each type protected?

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