Atlas Craftsman 101.07403 User manual

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Sears Craftsman lathes were manufactured by
Atlas Press Company and parts are interchangeable.

MANUAL OF
L A T
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OP ERATION
AND
MAC HINIS T S TA B L ES
ENG I NEERING DEPARTMENT
ATLAS PRESS COMPAN Y
1822 N or t h Pitcher Stre e t
Ka l amazoo , Michigan, 49001
Pr i ce
$2.50
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Twenty-third Edition
Copyrigh t ed
ATLAS PRESS COMPANY
P r inted in U. S. A.
Reprinted 1938, 1939, 1940, 1941, 1942, 1943, 1944, 1945,
1946, 194 7, 1948, 19~9, 1950, 1951, 196 2, 1954,
1955, 1957, 19 60, 1961, 1963, 1965, 1967.
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CONTENTS
1 .... . ... . .... .. . LATHE CARE AND CONSTRUCTION
2 ... .... ... . .. ... .. . ... THEORY OF METAL CUTTING
3 ......... . ........... .. . ... ...... . ... CUTTING TOOLS
4 ...... THE MACHINING OF VARIOUS MATERIALS
5 .. ...... .. . ... ... .. .... .. .. .. . .. HOLDING THE WORK
6 ... ........... .. . ... .... ... . DRILLING AND BORING
7 ..... ....... ... . .. . ... .. ..... ... .. THREAD CUTTING
8 .... .. LATHE ATTACHMENTS AND THEIR USES
9 .... .. .. WOODTURNING ON THE METAL LATHE
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. 11
.. .. .. .. . ....... . . . ....... .. .... MACHINISTS TABLES
. ... . .... . .. . ... . . ... ....... . ...... .. ..... .. ..... INDEX
12 .................... PAGES FOR YOUR SHOP NOTES
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SET OF FIVE WALL CHARTS
Printed blue-print style on durable ledger paper, Four charts
measure 16¼" x 21" - feature Decimal Equivalents, Thread
Forms and Formulas, Lathe Cutting Tools, and 60 ° V-Type
Thread Dimensions in easy- to-read form. The fifth chart
measures 35" x 23" and describes lathe parts and functions of
each. $1.00 per set,

PRE FACE
This Manual of Lathe Operation has been
prepared to pr ovide authentic, up to date, and
complete operating information for owners of
all types of metal cutting lathes.
Fundam enta l and concrete theory , as well
as operating pr oc edure, is included in order
to make this book suitabl e for students, ap-
prentices and vo cational schools. Much of the
data will prove invaluable to the machinist
and the more e xper ie nced lathe op e rator .
It is our hope tha t this Manual will further
the advancement of th e lath e us er in all walks
of industry. If we ha ve helped him , even in a
small way, the research and labor involved in
the preparation of this book will have been
well worth while.
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We wish to extend our sinc ere appreciation
to the many manufacturers , en gi neers and ma-
chinists who have assisted in the preparation
of the technical material in this material. If
the reader desires furth er info r mation on any
of the metals or pla s ti cs me ntioned , we will
gladly furnish the nam e and address of the
manufacturer.
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F 0 R
EW 0 R D
The history of modern machinery started in the last years of
the eighteenth century when Henry Maudslay, an Englishman,
built the first practical screw-cutting lathe. When compared with
a modern precision lathe, this machine was slow and clumsy, but
from the basic principles of Maudslay's lathe have come nearly
all modern machine tools. The skill of early New England
machinists in developing his theories soon put the United States
in the front rank among industrial nations of the world.
Henry Maudslay
1s
Screw Cutting Lathe
1800
Original Now at
South Kensington Museum
London, England
Courtesy Popular Mechanics Magazine
Today, more than 150 years after Maudslay, the screw-cutting
lathe is still the heart of industrial manufacturing. It seems odd
to consider the lathe so vitally important when large batteries of
automatic machines are used in every modern factory. But pay
a visit to the factory tool room where the machining is done which
makes possible the construction of these huge automatic machines.
There you will find a lathe, easily the most important tool, busy at
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the hands of an expert machinist turning the plans of designers
and engineers into new tools and machines for modern industry.
The lathe is the "King of All Tools"-more jobs of a mechan-
ical nature can be done on a lathe than with any other dozen tools.
In the machine s hop , experimental shop, or home workshop, the
metal lathe is ca lled upon for many operations. Turning, milling,
grinding, drilling and boring must be performed on iron and steel;
wood, plastics, alloys and soft metals must be shaped into form;
threads of all sizes a nd s hapes have to be cut; and machine parts
need repairing or replacing. Manufacturers, tool and die makers,
experimenters, automoti ve men, model builde rs , inventors-thou-
sands of businesses, hobbies, and professions depend on a preci-
sion screw cutting lathe with its many attachments.
THE MODERN BACK GEARED
SCREW-CUTTING LATHE
A Modern Back g eared Screw-Cutting La t he .
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LATHE CARE AND CONSTRUCTION
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PART 1
LATHE CARE AND CONSTRUCTION
SETTING UP THE LATHE
Most bench lathes are sh i pped completely assembled. All un-
painted surfaces have been greased thoroughly and wrapped in oil
paper, and the entire lathe strongly crated. Take care in removing
the crate-a crow bar or hammer can slip easily and damage some
part of the lathe. If the side boards are loosened at the bottom, the
entire top of the crate can be lifted off.
FIG. l
Bench Lathe ready
for domestic shipment.
All machined surfaces
are greased, and the
lathe is then wrapped
in paper and aolid1y
crated.
As soon as the lathe is unpacked, oil it comp l etely and thor-
oughly at all points shown on the Oiling Chart on pages 6 and 7.
Choose a well lighted location that is dry and with enough room
for maximum efficiency and convenience.
Floor stands and cabinets (page 2) make ideal supports for
the lathe. If the lathe is to be mounted on a bench, use one that
is solid ly built, well braced and with a good dry lumber top at
least two inches thick. The precision of any lathe, regardless of
size, depends a great deal upon the rigidity of the base under the
lathe bed - a flimsy, warping bench top can, in a few days, spoil a
careful mounting of the lathe and in time will impair its accuracy .
A bench height of 32 to 34 inches is correct for the man of
average height. Adjacent edges of the top boards should be care-
fully joined and planed smooth. It is suggested that the top boards
either be heavily dowelled, or th at four or five ¾" s teel rods , .
threaded at both ends, be run edgewise through all of the top
boards and pulled up tight . This latter method is pref err ed and
calls for an accurate boring job. The top should also be planed
smooth and level.
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2 M A
NUAL OF LATHE OPERATION
FIG . 2A ( Ri ght)
Lath e on fl o or ca bi net for tools an d
at tachme nt s with un dern e ath drive.
FIG. 2 (Left)
Lath e on flo or • tand. Thi s type of
moun ting provides a rigid support
and av oids impe rf ections of many
shop be nc hes.
LEVELING THE LATHE
The first step in successful lathe op e ra t ion is to keep the lathe
perfectly level at all times . When carelessly mounted any lathe
bed will be come twisted or bent, and with a slight amount of twist
the centers become out of alignment and accurate work is impossi -
ble. Expert machinist s agree t hat the better the leveling, the more
accurate the lathe.
Here is the proper way to mount and level the lathe : With the
lathe in position on the ben ch, mark and drill five ¼" holes for
machine bolts under the corresponding holes in the legs. Differ -
ences in height must th en be detected with a good machinists level.
Be sure the lathe bed is level ALL WA YS, including crosswise
and longitudin a lly n ea r both the headstock and tail s tock ends (see
Fig. 3) . Differences in height are then taken up by the use of wide ·
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LATHE CARE AND CONSTRUCTION
FIG. 3. Three Different Level Positions (only one level is required).
FIG. 3A
Approximate shim dimension.
3
shims to insure a firm base. Shims should be thin metal strips-
see Figure 3A for approximate size.
Repeat the checking operation after the legs have been bolted
down tightly. It may be necessary to relax the bolts and adjust
height by adding more shims. Most machinists check these leg
shims regularly and whenever the lathe is expected to be in use
for a long period of time. Before heavy work or whenever the
lathe is moved to a new shop location, it is advisable to repeat the
checking of the level position.
Do not slight the leveling of your lathe. In order to make
precision cuts on long work it is absolutely necessary to have the
bed perfectly aligned and horizontal. The precision built into a
lathe can be made entirely useless by faulty, uneven mounting.
Extra care and time spent in installation and leveling will give the
lathe every chance to perform the accurate work for which it is
built.
MOUNTING THE MOTOR
These lathes are designed to be run from a 1725 R.P.M. motor,
either ½ or ¾ H.P., depending upon the type of work being
handled . With the lathe in place, mount the motor on the motor
bracket and connect the switch wires as shown in Fig. 4. Before
bolting down the motor, run it for a moment to make sure that the
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4
WHITE
MANUAL Ofl LATHE OPERATION
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FIG. 4
direction of rotation is clockwise when facing the pulley end
of the shaft. If the motor pulley does not fit readily on the motor
shaft, scrape the pulley hole or dress the inside with emery
cloth wrapped around a wooden dowel. Sight along the edge of
the large pulley on the countershaft to obtain alignment with
the motor pulley. V belt drives require only medium tension, and
the motor drive belt should be adjusted with the tension lever in
the back position on horizontal countershaft and lowest position
on underneath drive lathes.
KEEP YOUR LATHE WELL OILED
Before using the lathe, oil it thoroughly at the points shown
in the chart on pages 6 and 7. It is well to memorize the exact
order of the chart. Use a good grade of machine oil - auto-
motive oil, S.A.E. No. 20, is excellent for general lathe use.
Both top and side surfaces of the bed ways should be oiled
whenever using the lathe. These ways, as well as all other un-
painted surfaces, should be covered with a generous film of oil
when the lathe is not in use. Keep the lathe completely covered
when it is a dusty location or standing idle for a long time . Some
types of gritty dust or soot are nearly as hard as emery dust and
will cause wear unless lathe bearing surfaces are protected. Be
sure to cover the bed ways during grinding operations.
Form the habit of oiling your lathe regularly.
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LATHE CARE AND CONSTRUCTION 5
FIG. 5 Modern Lathe Production Lines.
FIG. 5
CONSTRUCTION OF THE LATHE HEADSTOCK
The precision of a lathe depends to a great extent upon the care
taken in the manufacture of the headstock. The headstock shown
on page 8 is heavy, close-grained grey iron, ribbed and reinforced
for absolute rigidity and so l idly anchored to the bed. The front
of the headstock casting extends up to the bearing height, provid-
ing a heavy, per~anent truss between the right and left bearings
and insuring perfect alignment even under the heaviest loads.
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6
MANUAL OF LATHE OPERATION
IMPORTANT -LUBRICATE LATHE BEFORE OPERATING
LUBRICATION CHART
12-INCH METALWORKING LATHES
CODE
A - OIL DAILY with S.A.E. No. 20 oH
B- OIL WEEKLY with S.A.E. No. 20 oil
C - OIL MONTHLY with S.A.E. No. 20 oil
D - KEEP CLEAN ond well oiled at oil times
E- LUBRICATE gear teeth with Keystone No. 122 gear
lubricant, or e quivalent, to obtain smoo ther, mo re
quiet operation. Remove oil an d dirt before apply i ng
greas e.
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HEADSTOCK AND BACK GEARS
*Remov e screw lo oil bearings.
**Remove plug to oil bear ings .
CARRIAGE
*Remove scr ew to oil bearings and cross feed gear s,
HORIZONTAL COUNTERSHAFT
*Lubricate roclrnr-shaft pin at this point,
UNDERNEATH DRIVE COUNTERSHAFT
Note: Spindle drive shaft ball be ari ngs are seal ed
and require no furl h cr a tt en ti on :
TAILSTOCK -LEADSCREW -
LEADSCREW BEARING - RACK
*About once a month deem with kerosene and a brush,
th en cover with oil.
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LATHE CARE AND CONSTRUCTION
7
QUICK-CHANGE
LATHE
STANDARD CHANGE-GEAR
LATHE
QUICK-CHANGE GEAR TRAIN
*Lubri~ale gear bearings al these poinls,
QUICK-CHANGE GEAR BOX
STANDARD GEAR TRAIN
*Lubricale ge ar ,bearings ol these points,
STANDARD REVERSE GEAR BOX
KEEP YOUR LATHE CLEAN
Oil and dirt form an abrasive compound which can easily damage carefully fitted bearing surfaces.
Wipe the bed and a ll .polished parts with a clean oily rag at frequent intervals. Use·a brush to clean
spindle threads, gear teeth, lead screw threads, etc.
ATLAS PRESS COMPANY • KALAMAZOO, MICH., U.S.A.

8
MANUAL OF LATHE OPERATION
~61 ATLAS]
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F IG. 7 Lathe Hea d1 to ck
HEADSTOCK SPINDLE
The headstock sp indle is special alloy steel - accurately
ground and polished to extremely close tolerances to provide a
perfect surface for the bearing. The spindle diameter is 1¼ "-the
no se has 8-pitch National Form threads. A 25/32-inch hole is
bored through its entire length, allowing full-sized ¼ -inch stock to
be fed throu gh the spi ndle (see Fig. 2 12). The spindle nose is
reamed for a No. 3 Morse Taper, and a reducing sleeve is fur-
nished to permit the use of a standard No. 2 Morse Taper center.
TIMKEN SPINDLE BEARINGS
Lathes are equipped with Timken Tapered Roller Bearings
and are recommended whenever the l athe spindle speed must be ex-
ceptionally high for long intervals. These anti-friction bearings
are ideal for cont inuou s production jobs, wood turning and metal
spinning as well as the usual work at norma l speeds. A Timken-
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LATHE CARE AND CONSTRUCTION
FIG. 8
Lathe Headstock
Spindle is equipped
with Timken Tapered
Roller Bearings. Th e
tapered design and pos •
it,vely aligned rolls
mean that both radial
and thrust loads ar c
carried with minimum
of friction.
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equipped lathe also makes an excellent "combination machine" for
the shop handling quantities of both wood and metal work. Tim -
ken Bearings are pre-loaded to insure a tight bearing even under
the most severe use - th e tapered design and positively aligned rolls
carry both radial and thrust loads with minimum of friction .
FIG . 9
Timken bearin gs permit high speeds r equ ired f or polishing-m a chini ng sm a11
diameters, p las t ics , aluminum, e tc.
ADJUSTMENT OF TIMKEN BEARINGS
Adjustment of the Timken Bearing is not often necessary, but
if the spindle spins too freely or play is noticeable when the spin-
dle is pushed back and forth, the following simple procedure will
adjust the headsto ck bearings :
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10
MANUAL OF LATHE OPERATION
Run the lathe between thirty minutes and an hour to warm
up the spindle (a temperature rise of 50° Fahr. increases the
spindle about .002 inch between bearings). Then loosen the set
screw A (in Fig. 11) on the thrust nut, B, at the extreme left
end of the spindle, C, and turn it up to a point where no play
can be detected in the spindle. Advance this thrust nut 1/16 turn
past that point (equal to two teeth on the spindle gear) in order
to provide the correct pre-load. Tighten the set screw.
CARE OF TIMKEN BEARINGS
Lathes equipped with Timken Bearings can be set to work
immediately. Oil the bearings every time the lathe is in use with
S.A.E. No. 10 motor oil or a good grade of machine oil.
OPERATION OF THE BACK GEARS
The back gears reduce the lathe spindle speed, providing power
for heavy cuts and correct surface speeds for large-diameter work.
The back gear ratio is approximately 6 to 1. The back gears are
conveniently located, easily used and take up very little space.
Aluminum guards provide a safe ty covering. The mechanism for
changing from direct drive to back geared drive is quick and s imple
in operation. Adequate bearings and good gears are both vitally
important in lathe consruction.
The lathe back gearing mechanism is pictured in Figure 11, and
explains the details of operation. The "bull gear," D is keyed solidly
to the spindle. The small
gear, E, and the s pindle pul-
ley , F, are fastened together
rigidly - they have wide,
perfectly fitting bron ze
bearings for rotation on the
spindle. This small gear and
pulley assembly is free to
rotate unless the pin, G, is
pushed in, lo c king the pulley
to the bull gear and spindle.
In this locked position with
the back gears disengaged,
the s pindle is driven direct-
ly from the co untershaft.
FIG. 10
Top view of lath e head s tock showing
th e back gears ,
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