Manual of Lathe Operation and Machinists Tables1 PDF
Manual of Lathe Operation and Machinists Tables1 PDF
Manual of Lathe Operation and Machinists Tables1 PDF
Copyrighted
ATLAS PRESS COMPANY
Printed in U. S. A.
3 .. . . CUTTING TOOLS
7 THREAD CUTTING
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2 MA NU A L OF LA THE O PERA TI ON
FIG. 2 ( Left )
Lath e o n floor stand. This typ e 01
moun tin g provid e s a rig id support
and avoids imperfections of many
shop ben ches.
F I G. 2A (Ri gh t)
L athe o n fl oor cabin e t for t oo ls and
MOIOt H'MIN"1
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-
TO WI R£ OTH[R MAKE ~ O I O R S
FOLLOW M...I'4 Ur ....CTu RER S I NSTRuCTIO NS
FIG. 4
LUBRICATION CHART
12-INCH METALWORKING LATHES
CODE
A - O IL DAILY w-ith S.A.E. No. 20 oil
B - O IL WEEKn w;,h SAE. No. 20 oH
C - OIL MONTH.Y w;,h S.A.E. No. 20 oH
D _ KEEP CLEAN and well oiled 0 1 011 limes
E -LUBRICATE gear teeth with Keystone No. 122 gear
lub rica nt, or equiva lent , to obtoi n s moother , more
qui e t operat o n. Remove o il a nd dirt before ap plying
greas e.
TAILSTOCK LEADSCREW
LEADSCREW BEARING RACK
CARRIAGE *About On ce a month clean wit h kerosene and a bru sh,
*Remove scre 'of 10 o il bearings and cross fe e d gea rs. then cover with oil.
I'
HEADSTOCK SP I NDLE
The headstock spindle is special alloy steel - accurately
ground and polished to ext remely close tolerances to provide a
perfect surface for the bearing. The spindle diamet er is l )!,"-the
nose has 8-pitch National Form threads. A 25/32-inch hole is
bored through its entire length, allowing full-sized y,( -inch stock to
be fed through the spindle (see Fig. 212). The spindle nose is
reamed for a No.3 Morse Taper, and a red ucing sleeve is fu r
nished to permit the use of a standard No.2 Morse Taper cent er.
INDEXING MECHANISM
The face of the front spindle gear has 60 evenly spaced index
ing holes for such dividing operati ons as fluting, reeding, serrating,
sprocket- and spoke-spacing.
To divide the circumference of a piece of work into a giver.
number of equal divisions, mount the work and engage one of the
indexing holes by pressing lock pin through headstock. Perform
operation, release pin and, after consulting indexing table below,
rotate gear the proper number of indexing holes. Engage hole
and repeat operations until circle has been completed. NOTE:
When using lathe dog be sure that tail of dog fits tightly in slot of
face plate. In layout work it is advisable to use a pencil to mark
all required divisions before beginning the actual operation.
INDEXING TABLE
Divisons No. of Degrees Divisons No. of Degrees
Desired Spaces of Arc Desired Spaces of Arc
1 60 360 10 6 36
2 30 180 12 5 30
3 20 120 15 4 24
4 15 90 20 3 18
5 12 72 30 2 12
6 10 60 60 1 6
THE LA THE COUNTERSHAFT
The support bracket for the horizontal counters haft is mount
ed on the lathe bench. This type is "quick-change" with the
belt tension lever within easy reach for speed changes. Sixteen
speeds are available, ranging from 28 to 2072 RPM.
This modern countershaft design does away with the irritating
disadvantages of a cumbersome, space taking flat belt drive with
its limited speed range and difficulties of adjustment. It provides
a smooth, even flow of power to the spindle at the exact speed
most efficient for the work being done.
The countershaft spindle revolves on bronze bearings, amply
lub ricated through the hollow housing. These fine bearings trans
mit maximum power to the spindle and give years of trouble-free
performance.
FIG. 12A
FI G. 12 Lathes with underneath-drive hav e
Support bra cket for horizontal C011n two V -belts that turn lathe spindle.
tershaft is mo unted on lathe bench Upper co untershaft tUrns on ball bear
or stand. ings.
14 MANUAL OF LATHE OPERATION
FIG. 17
Special-built modern g rinding equipment of the type sh ow n above gives the fin al
pre c isio n finish to th e lathe bed ways.
Pull ing the knob control on the carriage apron engages the
power cross feed. The lever at the right engages longitudinal feed.
Both may be reversed by shifting t h e feed reverse lever located
on t h e left side of the lath e h eadstock. The compound can be
tu rned in a complete circl e, and it is graduated in degrees from 0 to
180, so that any angle can be cut wit h the comp ound rest.
ADJUSTMENTS OF TH E CARRIAGE
Four gib screws are located on the back of the carriage for ad
j usting h orizontal p lay between the carriage and the bed-these
screws should be tightened just enough to give a firm sliding fit
between carriage and bed. Bearing plates on the carriage, which
b ear on the under side of both t he front and the back bed ways,
anchor the carriage firmly to the bed in a vertical direction.
These bearing plates have shims for adjustment of possible wear.
FIG. 22
Arrangement of the reverse gears, gear train and change gears for standard change lathe.
FIG. 23
Quick change mechanism speeds
up thread and feed selections.
The tumbler lever with the small knob, located at the head
stock end of the lathe, is the feed reverse lever. This lever is used
to reverse or stop the rotation of the lead screw. Three holes are
drilled in the headstock providing three positions for the lever.
The center hole is neutral and the upper and lower holes are
24 M A NU A L O F L O\ THE O PER A TION
FIG. 26
THE T A ILSTOCK
The t a ilstock of a lathe m ust line up perfectly with the head
stock at any point on the lathe bed. The p recision of the gro und
ways and the extra care t aken in the fitt ing of t he t ailstock assu r e
accurate alignment at any posit ion. I
I
/
placing cent ers in the lathe, clean b oth external and in ternal t apers
t horoughly with a dry cloth. Any dirt or chips b et ween these
tapers will score both and d estro y their a ccu racy. D o not oil t he
tapers. E ven a sl ight fi lm of oil wi ll prevent a firm fit an d cause
t r ouble in turning.
THREADING GEARS
F IG . 30
Threading Gears .
Feeds a r e available for spring making. wire windi ng and ele ctrical
coil winding with all sizes of wire b etween N o. 12 and 40 B. & S.
and all types of magnet wire insulation. Multiple threads, machine
screws, pipe-type threads and special screws can also be cut with
the standard gears furnished. Complete set-ups and dir ections
for the most common threads and feeds are given in the Threading
Supplement.
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28 MANU AL OF L A T H E OPERAT IO N
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In Figure 35 a wood chis el is cutting a slice
across the end of a block of w ood. Here the
wedge of t h e tool acts to shea r off small sec
t ions, each one a sep
~
arate cutt i ng a nd
wedging act i on. If ~
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the wood fibers are
strong enough , thes e
small sections w ill
___________________
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cling together and re
sult in a curled chip . -~
F IG. 35
A wo o d chisel cutting across the end of a block of hard
wo od. Th e small s ections are ex a2"gerated in size.
j
FIG. 37
The false c utting edge formed at the tip of a tool bit.
The dark portion is deposited on the tool when takin g
heavy cuts. The wedging or cutting is done with t his
I
bit of metal, not the edg e of the t ool bit.
A tool bit that has been used on rather heavy cuts has a small
ridge of metal directly over the cutting edge. This bit of metal
i
is much harder than the metal being cut and is a lmost welded to
the edge of the tool, indicating that an immense amount of heat
and pressure was developed at this point.
This "false cutting edge" acts as the actual cutti ng edge in turn
ing. It is a decided advantage in heavy turning because it relieves
the edge of the tool bit from most of the work of cutting and
I
lengthens tool life. For conti n uous heavy cuts, the speed should
be k ept low enough, and the rake of the tool small enough in order
to build up this false edge. However, in taking fine finishing cuts,
this built-up edge should be avoided by tak ing finer cuts at higher
speeds and with larger rake angles.
There are several theories as to the forming of this false cut
ting edge. It is generally agreed, however, that the cutting action,
aided by the heat and pressure at the end of the tool bit, causes the
metal particles to deform or flow which produces what is called
II
"work hardening" of the metal. Whether it is due to the com
pression of a small strip of metal ahead of the edge of the tool
itself, or is simply a work-hardened portion of the main chip is a
I)
debated question. The important point to remember is that the
false cutting edge is desirable for heavy cuts-on fine finish cuts
I
it should be avoided. t}
I
34 MANU A L OF LATHE OPERATION
F IG. 3SA
T oo l bi t angles
wi th the tool bit
_ SIDE~K:-,A N GL:; horizonta l a nd at a
'------'
~
' ~ ...r
r ig ht an g le with the
center lin e of the
work
\ \ SIDE
\ CLEARANC E
~ ANGLE . HEE L
FIG. 3SB
T ool bit angles a s
designa ted for use in
th e tool holder.
S IDE
CLEARANCE
ANGLE FRONT CLEARANCE ANGLE
FRONT CLEARANCE GRINDING ANGLE
WORK SURFACE
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FIG. 3SC
Angles of the tool
bit in relation to
CE NTE RLINE OF
the work.
A
SECT ION A-A
FRONT
F IG. 40. Rou n d N o se Cutting Tool sui ta ble fo r
ro u g hi n 2" an d ge nera l p urp os e tu rn ing.
~~ SIDE CL EARANCE
ANGLE
~
SECTION A-A
SIDE
CLEA RANCE
ANGLE
FRONT
FIG . 41. E x cell ent R. H . Tool for genera l turning and s houldering
l ow OiIrd headstock ; a lso faci n g. P oint should be r ounded for
fi ni shing w ork.
I\
38 MANUAL OF LAT H E OPERAT IO N
I I
FI G. 45
J
GRINDING FRONT ANGLE GRI NDING TOP AND SIDE RAKE
FIG. 46. T hree view s of the process of grin ding a R. H. turn ing tool h it.
40 MANUAL OF LATHE OPERATION
~
chatter. Generally, how
~
ever, the tool should be set
FIG. 49
directly into the work or
at a slight angle as shown
in Figure 49. L11 11
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Holder. Used for cutting up U sed for general cutting Used for cutting up to shoul
to chucks, face plate, dogs, wher~ no clearance is need· ders, projections. etc., at the
etc. at the headstock end of ed. tailstock end of the work.
the work.
42 MANUAL OF LATHE OPERATION
FIG. 52
An excellent tool bit
for facing, designed to
cut from the inside
toward the outside.
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46 MANUAL OF LATHE OPE RATION
The speed s recommended for the various met als and plast ics
are for cuts of Ys of an inch or less in depth. The harder the metal,
t h e less t h e depth of cut should be. Ordinary turning does not
dem and unusually deep cuts- more met al per minute can usually
be removed by turning at recommended speed w ith a roughing cut
of between .100 and .125 inch in depth.
Finish cuts are taken after the rough ing cuts and should be \1
approximately .015 inch or less in depth, taken at the recommended
speed. T he work can be roughed down to within approximately
.015 inch of the final diameter, then finished with a sharp tool,
using light cuts. Before taking finish cuts to size be sure that the
i I
w o rk has cooled to a pproxi m ately room temperature-the shrink
age of a h ot p iece of work can easily spoil the intended fit.
T h e si x mo st common carria ge feeds are shown on the lathe
Il
t h rea ding cha r t: .0087 . .0070. .0060. .0050. .0035 and .001877
FIGURE 56
TABLE OF CUTTING SPEEDS
Correct Spindle Speeds to Give Approximately the Surfa
F IG. 57
Red ueing t.he diameter
o f a steel shaft -%." in
o ne cut. Except for the
exp e rienced machinist
cuts like this should
never be t aken - use the
s peed recomm ended for
t he metal being turned
a n d t a ke c uts of about
Va of an inch for rough
ing.
MACHINING STEEL
St eel is m anufactured in hundreds of grades, each with a differ
ent carbon and alloy content. The g rades of steel listed and de
s cri b ed in this Manual are carried in stock by most steel suppli ers.
They are p urchased from the w a reh ouse by their S.A.E. (Society
of Automotive Engineers) numbers, listed in detail in Part 10.
Some of the harder grades s h ould be purchased annealed for ma
chining purpos es.
The tool angles and cutti ng speeds given in Figure 59 are
a pproximate and will be found suitable for average work. They
50 MANUAL OF LATHE OPERATION
FIGURE 59
Bessemer Screw
Stock ... . . .. . . .. 111 2 100% 120 12 ' go 16 1/ , ' 22 '
Special Screw Stock X111 2 120 ISO 12 ° go 16'/, ° 22 '
High Manganese
Screw Stock ., _. . XI314 95 100 12 ° go 16'/, 0 22'
High Manganese
Screw Stock .... . X1315 95 100 12° g' 16'/, , 22 '
High Manganese
Screw Stock X1335 75 100 lZO go 16'/, ° 18 '
Open Hearth
Screw Stock ..... 1120 gO 100 12 ° go 16'/, , Ig '
Carbon Steel 1020 60 80 12 ' go 16,%° 14'
Carbon Steel .. . .... XI020 70 gO 12' go 16'/, ° 14 '
Carbon Steel 1035 62 80 12 ' go 16'/, , 14°
Carbon Steel 1040 61 gO 12 ° 8° 16'/, ° 14°
Nickel Molybdenum 4615 60 gO 12° go 16,%° 14°
Carbon Steel ....... 1045 55 70 10° go 12 ° 14'
3,%% Nickel Alloy . . 2315 50 80 10° go 12 ° 14°
3,%% Nickel Alloy .. 2320 50 80 10° go 12° 14°
3,% % Nickel A lloy .. 2330 50 80 10 0
8° 12° 14 °
3%% Nickel Alloy
Annealed .. . . . .. .. 2335 50 70 10 ' go 12 ' 14 '
Nickel Chromium
Alloy . . . .... ... .. 3115 50 70 10° go 12 ° 14 °
Nickel Chromium
Alloy ........ . .. . 3120 50 70 10° go 12 ° 14 '
Chrome Molybdenum 4140 50 70 10 ' go 12 ° 14°
Manganese Alloy . . TI335 50 60 10° go 12° 14 °
3'/,% Nickel,
Annealed . ... . .... 2340 45 70 10° go 10° 12°
3'/,% Nickel,
Annealed . . .. . . . . . 2345 45 60 10° go 10° 12'
3'/,% Nickel,
Annealed ... .. .. . . 2350 40 50 10° go 10° 12 °
Nickel Chromium 3130 45 70 10° go 10° 12°
Nickel Chromium.
Annealed 3135 45 60 10° go 10° 12 °
Nickel Chromium.
Annealed .. . .. .. . . 3140 45 60 10° go 10° 12 °
Chrome Vanadium.
Annealed .. . . . .... 6140 40 60 10 ° go 10° 12 °
FIG. 60
M achining a bushing
driver from tool steel.
The finished tool is also
shown. Tool ang les for
tool steel will require
some experim en ting On
the p ar t of the operator
-there are hundreds of
grades, each having dif·
ferent characteristics.
FIG. 61
Machining a forged machine
Front Clearance go
FIG . 63
Machining a stamless steel handle for use on a creamery plant machine.
These steels are often used where corrosion must be avoided.
F I G. 64
M a c h i ni ng a s olid
cop per e lectrode on
t he lath e. A fi n ished
el e c t ro d e i s a l so
s h ow n .
Cutting speeds for the various grades of hard bronze range be
tween 40 and 100 feet per minute - the manufacturer's recom
mendations should be followed. Use the .0087 inch feed w ith
moderately deep cuts ab out .030 inch in depth. No lubricant is
necessary. although. in turning some of the harder grades. kerosene
will be helpful.
60 M ANUAL OF LATHE OPER A TIO N
special tool bits- higher spe eds can be used and the cutting edge
of the tool stands up longer.
TOOL ANGLES: Tool bits for turning aluminum usually
have m ore rake on both side and f ront than for steel. The follow
ing angles are satisfa ctory for turning p ractically all t ypes of alum
inum alloys, both cast and w r ought:
MACHINING PLASTICS
The term "plastic" applies to many types of artificially pro
duced solids. One of the earliest plastics was celluloid - it has
been followed by various other plasti cs, moulded and cast from
such materials as phenol. urea, casein and cellulose acetate.
For machining purposes plastics can be divided into two groups:
Group I includes molded Bakelite, Formica and Durez, all of which
are phenol plastics moulded under heat and pressure. Group II
includes all of the cast and
formed plastics of var ious bases,
sold under such trade names as
Catalin. Plaskon, cast Bakelite
(called Bakelite T ransparent),
Marblette, ]oanite, Beetle, Amer
oid, Pyralin, Celluloid, Tenite
and Trafford.
MACHINING PLASTICS IN
GROUP I
The machining of plastics in
Group I is done best with special
tool bits, and if any quantity of
plastic turning is necessary, such
tools will save both time and
money. For a small amount of
machining, high speed tool bits
may be used, although it may be
FIG. 68
necessary to resharpen them sev
,M achining a salt shaker £rorn one of
the more commonly used plastics. The
eral times bef ore the job is fin
finished shaker is also shown. Note the ished. The tool should be ground
stringy appearance of the chip.
to these angles:
MACHINING MICARTA
Grind tools as for Formica gear m a terial. High sp eeds around
200 to 300 feet per minute are recommended, using the .0050 inch
feed, and light cuts of .0lD to .020 inch. Machine dry.
MACHINING TEXTOLITE
Use tools g round a s for Group II plastics. A v ery kee n edge
must be maintained and special tool b its should be used if any
quantity of t his material is to be machined. Cutting speed should
be around 200 feet per minute when using high speed tool bits and
300 feet per minute w ith special tool bits. T h e .0050 inch feed is
recommended with depths of cuts of .015 to .025 inch. All ma
chining is done dry.
MACHINING FI BER
Fibe r is an ext remely har d, tough material, mad e in the form
of sheets, rods and tubes and is used ext ensively d u e to its rela
tively low cost . I t is not commonly termed a p lasti c. T ools
should be ground w ith these a n gles :
FIG. 72
U sing the hermaphrodite caliper t o
locat e center p oints on the end of
round shafting. The four Jines have
been scribed to m ark the appro xim ate
center position.
FIG. 73
Us ing the center head to locate w ork center.
WOR\ ARBOR
TAILSTOCK
FIG. 77
The quickest way to countersink.
FIG. 82
Turning down a shoulder to fit the 1%" d0 i:. This method of adapting large work
FIG. 83B
H old ing rectang ular work in the
clamp-type dog.
tooth in the No. I , No. 2 and No. S the universal chuc k. Note that jaws are 2"rip.
jaws in order, and each jaw must be in pin&' the inside of the work.
FIG. 91
A proper method for removine
a chuck.
the lock pin on the face of the front spindle back gear. Put the
chuck wrench in its hole and pull as shown in Figure 91. If
necessary, tap the jaws with a piece of wood or a brass hammer.
Do not remove the chuck carelessly. You may damage the spindle
or chuck threads or drop the chuck on the bed ways.
ANGLE PL ATE
T OO L POST
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FIG. 96
How th e an gle plate centers a portio n o f an Irrerular piece of work .
FIG. 96
D raw-in c olle t chu c k attac hmen t s howin g uni ts in order of their assem bly
in t o th e lathe h eadstock: dr aw -in s pindle. t apered closing sl eeve. and s plit
ho lding collet.
FIG. 99
Turnin g a cast iron pulley on a mandrel
turned from round bar machine steel stock and the ends case-hard
ened if possible. Cast iron, with hardened tool steel plugs for the
ends, is often used in making a mandrel for large work. The
mandrel should be tapered about .006 or .008 inch per foot and
polished or ground. When finished, the mandrel diameter should
be a force fit for the h ole in the work and the tailstock end should
be .003 or .004 inch smaller. It is recommended that the mandrel
be turned undersized at both ends for about % inch to prevent
damage.
A mandre l is a precision tool f or ac
curate work and must be handled with
care. The ends are centered and counter
sunk exactly like other work. To make
removal easier, put a drop or two of oil
on the portion of the mandrel which will
gr ip the work. Never drive a mandrel
with a steel hammer without protecting
the end. The best tool for forcing a
mandrel in or out of the work is an arbor
press, or mandrel press (Fig. 100 ) . Be
sure the work is started perfectly straight
and on the entering end of t he mandrel.
FIG. 100
Pressing mandrel on bus hing Do not allow the tailstock center to be
before machining,
come too hot during the machining oper
ation.
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82 MAN UAL O F LATHE OP ERA TIO N
. LI P OR
~ SH~NK [~~~
UTTING
EDGE
TANG
FIG. 103
MARGIN
Twist Drill.
BODY
LIP
CLEARANCE
DEAD
CENTER C
FIG. 104
s
A
FIG. lOS
Drill g auge attachment for o rdinary hook rule or straight
Rte el r ule. Checks bo th length and angle of drill li ps.
~"
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DRILLING SPEEDS
When high speed drills are used, drilling speeds i n surface feet
per minute for the various metals are the same as the speeds for
gen eral turnin g given in Part 4. The upper p ortion of the
86 MANUAL OF LATHE OPERATION
REAMING
When a hole must be accurate to within .002 inch or less, it is
first drilled a few thousandths of an inch undersize and then hand
reamed or reamed on the lathe to the finish-diameter. Figure 112
shows a typical reaming job on the lathe. For best results, follow
the same rules in reaming as in drilling and general turning. Use
slow speeds, feed in evenly and be sure there are no burrs on the
reamer teeth. The type of reamer shown in Figure 113 is generally
used in the lathe.
FIG. 113
~ Reamer with
~ Morse Taper
shank for tail~
stock.
for most small shops. The met al s tan d has a h o le for each drill
with the drill size and its decimal equivalent clearly m arked. The
drills can also be purchased separately.
The tables in Part 10 of t his Manual give the decimal equiva
lents of the numbered and lettered drills and the prop er drills f or
use with vari ous sizes of taps. Drills in metric sizes are also avail
able.
BO RING OPERATIONS
FIG. 117
Boring the inside of a lar ge steel bushing. Note
high-spe ed boring tool mounted directly in tool post
fo r maxi m um rigid ity .
FIG. 120
T h i s dr awi ng s h o w s
how a certain an gle of
fr ont clea r a n ce m ay be
too s m all fo r one h ole
b ut sa tis fa cto ry for a
lar ger h ole . A t hA JJ th e
hee l of the t ool is rub
bing. A t "B " in t he
la r g er ho le th er e is amp le
clearance .
HE EL. OF T OOL RUBBING AMPlE CLEAR ANCE
Boring also requires smaller rake angles, and fi ner cuts and
feeds , due to two reasons: (1) t h e strength of the t ool edge has
been reduced by t he larger clearance and (2) t h e boring tool has a
tendency to twist and "spring." The tools shown in Figures 118A
and 118B are excellent for most boring operations.
BORING H IN TS
When enlarging an out-of-round hole. take several small cuts
rather than one heavy cut. This g r adual process avoids spring in
the tool- the final finish cut should be continuous .
94 MANUAL OF LATHE OPERATION
11
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F I G. 127.
60 degree type threads include the 60° Vee thread (Fig. 127) and
the American Nat ional Screw Thread, (Fig. 128). The 60° Vee
thread is cut very seldom, usually for small screws on which the flat
"~J! 3>4 A
wcj
hB,"o"t. 151';
¢+ ~ CLEARANCE
3" TO 5°
FI G. 129. Tool for cutting 60· type threads. Fig. 40 explains
how angle (fl must be determined.
MAJOR DIA.
OF THDS.
TO BE CUT
~ LENGTH -.I
FIG. 135 OFTHDS.
PREPARING THE WORK FOR AN EXTERNAL
60 ° NATIONAL FORM THREAD
The work to be threaded is firs t turned to the exact major di
ameter of the desired thread. The beginner often finds it h elpful to
turn the grooves C and D
(Fig. 135) to the exact min
or diameter. The size of the
minor diameter depends up
on t he form of the threading
tool. Theoretically, if the
thread were to be cut with a
sharp pointed 60 ° tool. the
minor diameter would be
equal to the major diameter
less the V ee- Form Double
Dept h of Thread (Table I,
page 110) or the major diam
eter less 1.732 X pitch. In
F IG. 136
common practice, however.
Correct setting of tool and compound rest
a tool bit is formed espe
when cuttine: a 60 rie:ht hand thread.
0 cially for a National Form
thread. and the correct minor
100 MAN UAL OF LATHE O PE RAT IO N
and advance the cross feed so that it is set at 0 w ith t he tool close
to t h e work. With the point of the tool about an inch to the right
of the start of the thread. advance t h e tool w ith the compound rest
so that the first cut will be about .003 inch.
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listed in Table II or Ta
ble III, pages 11 1 and WORK
112.
FIG. 141
Groove C permits the Grooves C and D help the beginner when
threading internally.
beginner to measure ac
curately the bottom o f the thread with a micrometer or caliper and
serves as a g ui de for depth. When the tool point has cut to the
depth of groove C, the thread has been finished. This outer g roove
COMPOUND
TO BE SET
FIG. 142
Correct setting of the
AT 29 °
tool and compound rest
line.
The grooves C and D can be omitted after the operator has learned
internal thread cutting operations.
104 MANUAL OF LATHE O PERATION
D; f + .010" F'.3707' p
W~. 3 707 x p -.0052" MINOR DIA.- MAJOR DIA. - (P+.020)
T_O_P_....
I~;'{SI DE
~ ID·APPROX.
FIG. 146. T o ol bit form ed fo r
r \ i,ll,
\ II TOP V
q~~ ,""J~m""
FIG. 147 (Left)
Tool bit formed for cut
t ing an internal Acme
th read. T o dete rmine an
angle <1>, refer to Figure
F MINUS .006"
~1;1 TOP 1
, I aq
I~¢ PLUS CLEARANCE ANGLE
, . . . . - - - - , - - .-,.;:.~::::::---------r-
FRONT
~F .OO~"
c
MINUS
~CLEARANCE ANGLE
f
b.£ I
a
F I G. 150
Determining the angle cp. Dra w line
"a b" equa l to the circumference of the
thread (3.1416 X major diameter) . Then
draw line "ac " at right angles to flab"
:J
a nd eq ml in len gth to th e th r ead pitch
(o r lead, if a multi ple threa d ) . Draw lin e F IG. 151
"bc ." The a n gle q, is eq ual t o the ang le T ool bit fo r c uttin g internal
In or d e r to c u t t he
Americ an Sta nd ard Pipe
thread on the lathe without
sp ecial d ies or equi pment,
some v ari a t ion in for m is nec
essa ry. Excellent p ipe-type
thread s, satisfactor y for com
m ercial use and having the -n/ WORK
TABLE I
DEPTH AND DOUBLE DEPTH OF NATIONAL FORM THREADS
This table shows (I) Depth and Double Depth for National
Form Threads cut with a NF formed tool, and (II) Depth and
Double Depth of NF threads cut with a 60 0 V-type tool, making a
V bottom but leaving top of thread with proper amount of flat
(see text, page 97). Two columns at extreme right give proper
depth of compound feed to obtain correct depth of thread with
compound rest at 29 ° (page 99).
TABLE III
(Formerly S. A. E.)
·Clearan c e drill makes h ole with standard clea rance fo r d iameter of nominal size.
114 MANUAL OF LATHE OPERATION
TABLE V
·Clearan c e drill makes hole with s tandard c1earance for diameter of nominal size.
116 MANUAL OF LATHE OPERATION
TABLE VIII
INTERNATIONAL STANDARD-METRIC
THREAD DIMENSIONS AND TAP DRILL SIZES
TABLE X
ACM E STAN DARD THREAD DIMEN SIONS
Width of
Threads Pitch Depth Double W idth of Spa ce at
Inches of Depth of Top of B o ttom of
per Inch P Thread Thread Thread T hread
RIGHT HAND
Q U ICK-CHANGE
LE V ER
CONTROLS
A . Left Hand Quick-Change Lev er - shifts to five positIOn s
A, B, C, D and E - sh own on left end of chart. The position
of t h e lever is indicated at the left end of the row of numbers
in wh ich you find the thread or feed desired.
B. Righ t H and Quick-Change L ever - shifts to nine positions.
They are numbered on bottom row of chart beneat h carriage
feeds. T h e indexing position of the lever is always directly
below the thread or feed des ired.
124 MANUAL OF LATHE OPERATION
When only one of the two gears meshes with another gear in
the train, this gear is called an "Idler." The other gear, or spacer,
is called a "Spacer" gear and does not mesh with any gear in the
train.
The positions of the gears on the stud assemblies are denoted as
"N"and " F" i n the gear set-up tables. " N" position means the gear
or spacer is positioned on stud NEXT TO Quadrant- "F" position
is gear or spacer A WAY from quadrant. "SS" denotes that a
double-keyway steel spacer must be used on gear st ud.
S TU D B U S H ING
NUT
ID LE R BO LT
G EA R
GEAR CLEARANCE
When setting up the gear train, be sure to allow sufficient
clearance between two meshing gears (Fig. 166). Gear clearance
does not reduce the accuracy of a thread cutting operation, because
all play in t he gears is taken up in one direction. A method often
used to obtain proper gear
clearance is : (1) Place a
sheet of thick writing paper
between the teeth of the
two meshing gears, (2)
CLEARANCE
CLEARANCE tighten gears in position,
and (3) remove paper. A
small amount of grease,
preferably graphite grease,
applied to gear teeth will
often aid in obtain i ng
smoother. more quiet opera-
FIG. 166
Proper gear clearance. tion.
128 MANUAL OF LATHE OP ERATION
LUBRICATION
Lubricate Regularly - use S.A.E. No. 20 Machine Oil.
I
1. All the lubrication cups
on the gear housing are
shown in illustration at
right. Put a few drops
of oil in each oil cup
once a week if lathe is
used constantly.
2. Qu ic k-Change lever
bear in gs a nd shaft
oil once a week.
Occasionally apply a
small amount of heavy
outer gear lubricant
to the feed gears and
tumbler gears-it will aid in obtaining smooth er, more quiet
operation. IMPORTANT-Make sure all oil has been removed
from the gear teeth before applying lubricant or it will n ot
adhere.
130 MANUAL OF LATHE OPERATION
TABLE I
GEAR SET-UPS FOR METRIC THREADS
Left Ri.:ht
Position A Position B PositionC Position D Com- Hand Hand
Pitch in English pound Lever Lover
Millimeters Equivalent N F N F N F N F Gear Position Position
7. .27560 48 55 40 44 55 24* 32 A
FIG. 168
Left end of lathe with gear guard
open, showing change gears, gear train,
and location of threading chart.
POSITION D
FIG. 169. Gear bracket positions.
The outer end of the longest bracket slot is called "Position A,"
the inner portion of the same slot is "Position B." The short slot
adjacent to the long slot is Position "C," and the next short slot is
Position "D." These gear positions are approximate-they will
vary with the size and number of the gears composing the train
(see diagrams in Fig. 170 on the following page).
CHANGE GEAR STUD ASSEMBLY
Before setting up a train of change gears, examine one of the
change gear stud assemblies which hold the change gears to the
gear bracket (Fig. 171). Each stud assembly has an outer gear bush
ing long enough to accommodate two gears. The gear bushing has
a double key which fits into the keyways in the gears. The gear
bushing and two gears fit over a stud bushing, and the assembly
is bolted to the gear bracket. The washer is a bearing for the outer
end of the gear bushing.
l- E-;
Vl
(/)
~ p::
W
:c 0
I- ~
Z E-;
0 p::
l!) ~
z :r:U
i=
I-
::>
() d
Cl Z
H
jj 0
'"
:c
I
~
~
p::
:r:E-;
136 MAN UAL O F LATHE OPERATION
N
ID LE R BOLT
TUMBLER GEARS
TUMBLER GEARS
20TOOT H
SPACER GEAR
For quadruple threads of this lead engage the half nuts at any
of the four mainmark ings for the first groove, at any of the "a"
positions for the second groove, at any of the "b" positions for the
third groove, and at any of the "c" positions for the fourth groove.
The setting of the compound rest feed is changed only after each
of the four grooves has been cut to the depth of setting.
TUMBLER GEARS
40 TOOTH 6EAR
64 TOOTH
GEAR
The threading dial can be used when cutting threads below marked "Exact"
in the column under "Accuracy per inch", except for the 1.25, 2.25, 2,75,
3.25, and 3.75 threads. These threads and all others must be cut in the
same manner as metric threads (See Page 109). Extra gears available from
the factory at nominal cost.
---
Threads Accuracy Gear on Position D Position C Position B Position A Spindle
Note
per inch per inch Screw B F B F B F B F Stud Gear
Six different carriage feeds between .0027 and .0085 inch per spindle rev
olqtion ~re available on the Master Craftsman lathe in addition to the five
most common feeds which are pictured and described in detail between
pages 135 and 149. When the material or job requires a certain feed, refer
to the table below. Extra gears are available from the factory at nominal
cost.
SYMBOLS:
FIG. 187
Left end of lathe with gear guard
o pen, showing change gears, gear train,
and location o f threading chart.
POSITION B
The outer end of the longest bracket slot is called "Position A,"
the inner portion of the same slot is "Position B." The short slot
adjacent to the long slot is Position "C." These gear positions are
approximate-they will vary with the size and number of the gears
composing the train (see diagrams in Fig. 189 and on the following
page).
CHANGE GEAR STUD ASSEMBLY
Before setting up a train of change gears. examine one of the
change gear stud assemblies which hold the change gears to the
gear bracket (Fig. 190). Each stud assembly has an outer gear
bushing long enough to accommodate two gears. The gear bush
ing has a double key which fits into the keyways in the gears.
The gear bushing and two gears fit over a stud bushing, and the
assembly is bolted to the gear bracket. The washer is a bearing
for the outer end of the gear bushing.
158 MANU AL OF LATHE OPE RATIO N
NUT
IDLE R BO LT
GEAR BU S HING )
FIG. 190. Cross section of change gear stud assem bly.
Notice that in order to make t his assembly complet e, two gears
must be mounted on the gear b ushing at one t ime. W hen bot h of
the gears on a gear bushing mesh w it h other g ears in the train,
they form a "compound" gear a ssem bly. W hen on ly one of two
gears on a gear bushing m eshes with t he other gea rs in t he t rain,
it is called an "idler." Th e sm aller gear, which is mou nted on the
gear bushing with an idl er, is called a "spacer" gear and does not
mesh with any gear in the train ( s ee Fi g. 195) .
GEAR CLEAR ANCE
When setting up the
gear train, be sure to al
low sufficient clearance
CLEARANCE CLEARANC E between two meshing
g ears (Fig. 191). Gear
clearance does not reduce
the accu racy of a thread cut
ting operation, b ecause all play
in t he gears is t aken up in one di
recti on. A met ho d ofte n used to ob -
FIG. 191 tain proper gear clearance is : (1) Place
a sheet of thick writing paper between th e t eeth of the two meshing
gears , (2) tight en gears in position, a nd (3) r emove paper. A small
amount of greas e, preferab le graphit e grease, ap plied to gear teeth
will often aid in obtaining smoother , m ore q uiet operation.
THE REVERSING MECHANI SM
Right hand threads are cut with the carriage traveling toward
the headstock. Left hand th re ads are cut w ith t h e carriage travel
ing toward the tailstock.
Whenever a new gear train has been set up, shift the tumbler
gear lever to test the direction of the carriage travel. Because
some set-ups are simple-geared and some are compounded, the
carriage travel may be right for on e set-up an d left for another
set-up, even though t h e l ever has b een shifted t o the same position
in each case. A lways test th e directi on of carriage travel before
starting to cut a thread.
160 MANUAL OF LATHE OPERATION
TOOTH GEAR
CHART
32 TOOTH
GEAR
STEEL
SPACER
F I G. 196. G ear sot-up fo r 72 an d 80 t hre ads p er inc h .
T HRE ADS
TUMBLER
GEARS
GEAR
TOOTH
GEAR
FIG. 200. Gear set-up for .0078 inch carriage feed (see page 167).
168 MANUAL OF LATHE OPERATION
Table I-Continued
51
1/400 54B
36 56 56 46 32 h
52
Exact 52F
xxS 64I 16
53
1/3000 54B
40 64 54 44 32
54
Exact 54F
xxS 64I 16
55
1/7000 64B
44 64 52 44 32
57
1/320 56B
24 44 40 36 32
58
1/580 54B
32 54 56 44 32
60
Exact 48B
32 40 xxS 64I 16
61
1/1500 54B
46 52 xxS 56I 16
62
1/620 48B
20 44 54 46 32
63
1/2100 64B
24 40 52 44 32
65
Exact 48B
32 52 40 24 32
66
1/75 44B
36 54 xxS 64I 16
69
Exact 54B 36 46 xxS 64I 16
70
Exact 40B 48I xxS 32 56 16
71
1/710 64B 36 40 xxS 64I 16
73
1/730 48B 20 36 xxS 44I 54 32 32
75
Exact 40F 36 24 32 40 xxS 44I 16 d
77
Exact 44B 32 56 xxS 54I 16
78
Exact 54B 36 52 xxS 64I 16
79
1/790 54F 52 40 32 36 xxS 44I 16 (*)
SYMBOLS:
.6 56B 36 64 44 52 32
.7 64B 24 32 44 52 32
.75 64B 32 40 44 52 32
.8 54B 46 64 44 52 32
.9 46B 36 52 44 52 32
1.0 40B 32 48 44 52 32
F IG. 205
FIG. 206
Stead y rest su pporti n g shaft for
facing end .
178 M ANUAL OF LATHE OPERATION
Fl O. 210
Using both the s tea dy rest a n d follower rest to support a lo ng, small·diameter rod.
"Y'C'
~ }-
90·
- CUT OFF
TOOL -l~\~\~
FIG. 214
TH E CARRIAGE STOP
F I G. 218
Carr ia ge Stop.
FIG. 219
A repeat operation requiring
bo th the carnage stop and the
cross s li de s top. The bar is
bein g fe d t hrou gh the beadstoc k
s pin dl e.
F IG. 222
Milling At tach m en t.
holding arbor ) .
a.~~
F IG . 230
Holding collet set for holdin g mi1!ing
cutters. T his set consis ts o f : draw
bar. sleeve, and an arbor for straight
shank cutters. Collet bushings ar e re
til quired to adapt end mills to the arbor
of this set.
shank cutters. Two arbors are availab le for threaded a ngular cut
ters. A collet b ushing or arbor is also required for a ll st rai ght shank
end mills except the Yz inch diameter. The Woodruff keyway cut
ters are h eld directly in t he collet arbor w itho ut bushin gs.
P ass the draw bar through the spindle and tighten t h e arbor
into spin dle taper by turning handwheel. T ight en cutt er in arbo r
by locki n g socket-head set screw. The draw bar, arbor, bushing,
cutter shank and lathe spindle must be wiped clean and dry. When
mounting the mi ll ing cutter in the coll et arbor, be sure t o select
the proper size of collet bushing if one is r equired.
W oodruff Cutters
1/ 2" x 1/ 8".. .. .. 164 266 418 418 500 685 68
3/ 4" x 3/ 16" . ... . 164 164 266 266 418 418 50
1" x 1/ 4" .. ...... 112 164 164 266 266 266 41
1-1 / 8" x 5/ 16" .... 112 112 164 164 266 266 26
1-1 / 4" x 3/ 8" . .. . . 83 112 164 164 164 266 26
Angular Cutters
1-1 / 4" x 7/ 16" ... . 83 112 164 164 164 266 26
1-5/ 8" x 9/ 16" . . .. 70 83 112 112 164 164 26
DIMENSIONS OF STANDARD KEYS AND K EYWAYS
-jAr V=
I
8
1 I
E
Nominal
SIze of
Key
V Ys X 7"2-2 - - .1250
A X B
Width
of Key
Min.
A
D iam .
of Key
Min.
B
.490
Heigh t
of Key
C
.198
Distance
below
Center
E
%4
0 Ie ft x Y4
Y4 x Vs
.1875
.2500
.740
.865
.308
.370
)16
lIJ~
h xl .3125 .990 .433 )1 fi
FI G. 232 YsxlY4 .3750 %4
1.240 .54 2
Note: Allo w ab le oversize of di mensions A and B is .0 10"-of dimens io n C is .006 ".
Optimum key w idth is e qual to one-quarter the shaft diameter. Keys s hould h e c hosen to
appro x imate this relation as closely as possi ble.
DIMENSIONS OF WOODRUFF KEYWAY SL OTS
Nominal WIDTH W DEPT H H
Key Size
AXE Max. Min . Max. Min.
r~tr ~
Radius Keywa y Ke y way
Size W X H D epth Dep th
i 7"2 %2 X%2 .020
D
%4
C
?64
H
%-Vs ~x~ %2 ~6 lh6
~:
Y4X7;l
~
I %4
1~ %6 X0/16 )16
17"2 YsxYs Y:16 %2 %2
lY4 ~1 6 x VI6 )1 6 %6 7;1
2 %X7"2 )1 6 ?10 o/J6
27"2 %x% )16 ~~ 1%2
3 ~ X 3/.1 %2 Y<I 7"2
FI G. 234 3~ VsXVs %2 Ys %
4 1 X 1 %2 3/s %
Note : When a s quare key is used, dimensions D an d C are no t equal except on the smaller
shafts. If des ired . a flat key with a dimension H equal to twice dimension D can be used.
FIG. 245
Drum - type re vers
ing switch mounted
on head s tock guard.
EXTERNAL GRINDING
Remem ber t h a t grinding is a finishing operation. The work
should be turned as close to t h e final fin ish size as possible before
the g rinding operation is begun.
With the w ork and the grinder mounted in position and the
grinding wheel d ressed prop erly, ad vance the w h eel into one end
of the work. T ake light cuts across the entire length of the wor k.
If usi ng the autom a t ic carriage feed, set up the change gears for
the .003 5 inch feed. Hand feeds should be very slow and even. The
last finishing cut should b e less than .001 inch-very often a last
pass is taken w ithout advancing the feed. When hardened stock is
being ground. redress the wheel before taking the final cuts.
With t he center and sleeve mou nted in the lathe sp indle, dress
external wheel with the compound r est set a t exactly the p r op er
angle. Adjust belts to obtain a slow lat h e spindle spe ed and s hift
reversi n g switch lever so that lath e spindl e is turning in a direc
tion opposite that of the grinding wh ee l. Feed up to the cent er
with the carriage handwheel, lock carriage in p osition and feed
a cross center slowly with compound rest feed. Take light cu ts.
NOTES ON GRIN D IN G
A spotty, mottled surf ace usuaIly m eans that it is tim e to dres s
the grinding wheel.
See that the work is held rigidly- vib rati on ca uses poor w ork.
No lubricant or cutting com poun d is n ecessary exce pt fo r
production work .
Keep the tool post g rinder clean and w ell oil ed. T he bearings
are grease packed at t h e tim e o f assem bly and need no furthe r
attention.
Always Ta k e L ight C uts W hen Grinding.
196 MANUAL O F LA THE O PE RATION
FIG. 261
FI G. 260
Motor D riven M ica Undercutter.
1,~ }rif~'
I·
F I G. 264.
'd·
Taper showing dimensions -
.)
see text below.
EX A MP L E : Figure 264 shows a taper with a diameter of 3
inches at one end an d 2% inches a t the other.
Diff er ence in d iame ters = .500 inch.
10
L engt h of taper = 10 inches = - foot .
12
10
Th en . taper p er foot = .500 --0- = .600 inch.
12
FOR MULAS:
Large diameter - Small diameter
Tape r per foo t ( in in ches )
Length in feet
12 ( L arge diameter - Small diameter)
-:
Length in inches
L a r g e d iameter - Small diam eter
Taper p er f oot (in inches)
Length in inches
CA L CULA TING ANGLE O F COMPOUND REST
The lathe compound r est ca n be swivelled a n d locked at a ny
angle, a n d is ideal for cutting shor t tapers, taking angular cuts up
to 2Y4 inches in length, and boring tapered hol es. When the de
s ired taper is expressed in degrees and minutes, the angle is simply
t ransfe r r ed to t he p rop er si de of t he 90° reading on the graduated
base of t h e compound rest (compound rest reading is exactly one
half of total in clu ded a n g le of tap er) . When the taper is expressed
in inches per foot, convert this figure into degrees and minutes,
first fi nding the tangent of th e d esired angle as f ollows :
Taper per Foot in I nches
T angent of Angle = - - - - - - - - -
24
Then consult the tang ent tables i n any machinists handbook
(see page 200) to ob t ai n th e equ ivalent of this tangent in degrees
and minutes.
200 MAN UAL OF LATHE OPERATION
{
FIGURE 266 TABLE OF TANGENTS
As explained on page 199, a table of tangents is essential in converting
taper per foot into degrees and minutes when calculating the proper se t
ting of the compound rest for taper cutting. In the table below, tangent s
are listed for every 15 minutes of angle. To obtain angles for interme
diate tangents, use interpolation. For example : The tangent of the taper
in t h e example on page 185 is .024975, which is between the tangent read
ings of 1 0 15' and 10 30'. The exact reading is obtained as follows : [
.02618 - .02182 =
.00436
.024975 -.02 182 =
.0031 55
.003155
X 15 min. = 11 min.
.00436
,
.50404
.01745 14 0 .24933 27 0
I
0 .50952
15 .02182 15 .25397 15 .51503
30 .02618 30 .25862 30 .52057
45 .03055 45 .26328 45 .52612
0 .03492 15 0 .26795 28 0 .53171
15 .03929 15 .27263 15 .53 732
30 .04366 30 .27732 30 .5429 5
45 .04803 45 .28203 45 .54862
3 0 .05241 16 0 .28674 29 0 .55431
15 .05678 15 .29147 15 .56003
30 06116 30 .29621 30 .5 6577
45 .06554 45 .30096 45 .571 55
4 0 .06993 17 0 .30573 30 0 .57735
15 .0743 1 15 .31051 15 .58318
30 .01870 30 .31530 30 .58904
45 083 09 45 .320 10 45 .59494
0 .08749 18 0 .32492 31 0 .60086
15 .09 189 15 .32975 15 .6068 1
30 .09629 30 .33459 30 .61280
45 .10069 45 .33945 45 .61882
0 .1051 0 19 0 .34433 32 0 .62487
15 .63095
I'I
15 .10952 15 .34921
30 .11393 30 .35412 30 .63707
45 .11836 45 .35904 45 .643 22
7 0 .12278 20 0 .36397 33 0 .64941
15 .12722 15 .36892 15 .65563
30 .13165 30 .37388 30
45
.66 188 I
45 .13609 45 .37887 .668 18
0 .14054 21 0 .38386 34 0 .67451
15 .14499 15 .38888 15 .68087
30 .14945 30 .39391 30 .68728
45 .15391 45 .39896 45 .69372
0 .15838 22 0 .40403 35 0 .70021
15 .16286 15 .40911 15 .70673
30 .16734 30 .41421 30 .71329
45 .17183 45 .41933 45 .71 990
10 0 .17633 23 0 .42447 36 0 .72654
15
30
45
.18083
.18534
.1 8935
15
30
45
.42963
.43481
.44001
15
3D
45
.73323
.73996
.74673
r
11 0 .19438 24 0 .44523 37 0 .75355
15 . 19 391 15 .45047 15 .76042
30 .20345 3D .45573 30 .76733
45 .20800 45 .46101 45 .77428
12 0 .21256 25 0 .46631 38 0 .78128
15 .21712 15 .47163 15 .78834
30 .22169 30 .47697 30 .79543
45 .22628 45 .48234 45 .80258
202 MANUAL OF LATHE OP ER ATION
AMOUNT OF
SET OVER..)
_I ~ NORMAL CENTER LINE
FI G. 267
Details of a tap er cut by
setover o f t ailstoc k .
"A~
The taper cu tting atta chment shown in Figure 272 has many
advantages over the tailsto ck setover method. L athe centers are
n ever taken out of alignment ; bea r ing surfaces of the lathe centers
a re n ot affected; dupli cate tap ers may b e cut quickly on pieces
of different length; and taper b oring, impossible with tailstock
s etover, is handled quickly and easily . Th e index plate is grad
uated in deg rees an d taper p er foot (in inches), simplifying
computation and setting.
The slide bar is installed parallel to the lathe bed way and
set at the desir ed angle. A slotted draw bar connects the slide
bar and the car ri age cross slide, guiding the cutting op eration.
MORSE TAPERS
Standard Morse Taper dimensions are shown in Figure 276
The taper per foot varies for each size. When cutting Morse Ta
pers, it is preferable to set the lathe for the proper taper per foot,
rather than to measure the large and small diameters.
IMPORTANT!
When cutting tapers, always have the point of the tool bit on
the exact lathe center line. Be sure to check the taper in a
standard socket before the final cuts are taken.
208 MAN U A L OF LATHE OPERATION
t; ~1;
o- "' u
o~
~g
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~
-s .i "" . ~
- -5" -5"
~
0"
.. '"
'" . _"'" '"
.c" '"
.s::" ~"
o
~.s::
~
oo .c ...
"
'" OD C
.... ::1 -
- ii:.o W,s
.".t: -0 ::I "
-o..u
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-.s::
_u _u .a
:::O S:::
:g .... 0"
.cu
....
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....c _ u
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rr. ~
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" . o "•
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"0 .
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" v u ....
~ . k'"' • o • k k o
'0", "E.5
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: ~ ~~ ." "0
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~OC:ll ~~ ~ .; .c .; _.i ~ ~ -5 ~
.".a. '" ,.!:d ::J ... ::J 0 ::1 ~" ;~
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eo. .- '" -'" 0-
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r:: t: r::: ."" "'c ." " '1:'3 >.. c:: >. .,,>, "0- "'"
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D A B S H P T B d a w L K
o .252 .3561 2H 2;' 2", 2 ,p. 'U. ,p. .235 .04 .160 ,.. Ht .62460 .05205 0
.369 .475 2 ,.. 2 ". 2 ,.. 2'A1 Ii % ,'. .343 .05 .213 % 2". .59858 .04988
2 .572 .700 3 'A1 2H 2% 2,.. 'U. ". 'U. H .06 .260 '% 2'h .59941 .04995 2
:{ .778 .9il8 :l % :l H 3'U. 3 .... f, ,.. I. B .08 .322 1,... 3.... .602:lfi .05019 3
4 1.020 1.231 4'% 4% 4'A1 4 ,.. B % f, B .10 .478 1'U. 3'% .62326 .05193 4
5 1.475 1.748 6'A1 5 '% 5'U. 5.... % % % 1 §! .12 .635 1'h Ht .63151 .05262
6 2.116 2.494 8,.. 8 'U. 7% 7'4 % l'AI 'h 2 .15 .760 1%. 7 .62565 .05213 6
72.7503.27011 % 11,/. 10 .,. 10 1.,. 1% %. 2% .181.1352% 9'1.. .62400 .05200
212 MANUA L OF LATHE OPERA TI ON
METAL LATHE
,; ar-
FIG. 284. Screw Cente r. FIG. 285. spu7' Center. FIG. 286. Cu p Cente r .
These tnr ee c en t ers are com p anion pieces fo r wood tu rning on t he metal lath e. Each
center h a s a No. 2, Morse Tape r shank. The sc r ew cent e r (Fig. 284) is mounted in t he
heads tock for fa cing a n d holl owi ng o pe ratio ns. The spur center (Fig. 285) is u sed in t h e
h eadstock t o drive wo rk mounted betw een lathe centers. The cu p center ( Fig. 286) a cts
as a dead cen ter in the tailstock.
F I G. 29 0 Chisel S et
I
center into center of work just far enough to pr ovi de a firm bear
ing. Revolve work b y hand to see if work turns f reely; if it is too
t igh t, back off t he cup center slightly. L arge pieces of square or
rectangu lar stock will turn much more easily if th e corner edges
are pla ned befor e the work is mounted.
N o. 10 m otor oil or equivalent is an excellent lubricant for t he
tailstock center. However, s ince oil p en etrates quickly into the
work, it shoul d be u s ed only w hen there is plenty of waste stock at
t h e tai lstock end. With a small amount of waste stock, paraffin or
beeswax is the b est lubricant.
TURNI NG BETWEEN CENTERS
The beginner
should practice
turning scrap
stock between
centers before at
temp t ing more
difficult ope r a
t ions with expen
sive woods. The
two most com
monly used chis
els, the gouge and
s k ew (Figs. 293
F I G. 293 and 298, can be
Ro ughing out square stock with the large g ouge.
handled in a satis
factor y m a n ner a f ter a short period of practice and study.
T h ere are two methods ordinarily used in wood turning opera
tions: "paring" and " scrapin g." T h e paring method described in
the following paragraphs, although the more difficult method, re
sembles more closely a true cutting action and usually results in a
bett er class of work. The scraping method for face plate work is
described on page 226.
TAKING THE CUT
As a g~neral rule, t he proper tool motion is parallel with the
grain of t he work. Always cut from t h e center toward the ends of
the work - never start cuts at an end. When turning a taper,
always cut t oward the smaller diameter.
When t a k ing t h e first cut s on rough stock, set th e tool rest
about 3/ 16 in ch fro m the work and about Ys inch above the lathe
216 MANUAL OF LATHE OP ERATI ON
The large s kew chisel ( Fig. 299) is used for smooth cutting on
cyli ndrical or long taper work. The cutting edge is "askew," or at
an angle, and both side faces a re ground to permit cuts to both
the right and left.
When sharpening the large skew, the sides are ground off
equally to an angle approximately equal t o that shown in F igure
299. A fi ner cutting edge results in a cleaner cut, but becomes dull
quicker than a large cuttin g angle. The ground surfaces should
be flat- hollow grin ding makes it difficult to hold the tool in the
218 MANUAL OF LATHE OPERATION
Figure 304 shows how the parting tool is used to cut grooves at
various p oints of work which is to be turned to a required shape.
Each groove is cut nearly as deep as
the finish-diameter, allowing be
tween 1/ 16 and 3/ 32 inch for finish
ing. The proper tool position is
shown in Figure 306. Beginners
should hold the tool with both
hands and remove the tool when
taking measurements with the ca li
per. Do not Cllt too deep. Experi
enced wood turners cut and caliper
the sizing grooves at the same time
(Fig. 305), a method which saves
time and reduces the possibility of
cutting the groove too deep.
FI G. 305. Measuring the depth of When using the parting tool fo r
a groove while it is being cut.
cutting off waste ends of the work,
cut groo ves at both ends so that the diameter is about 74 inch at
those points. Then cut the tailstock groove another Ys inch or
slightly dee per. Now cut entirely through the headstock end and
catch the work as it drops. The small skew chisel gives a smoother
cutoff than the parting tool
( see p age 224) . Some oper
ators prefer to stop the
/'
lathe when the groove di I
ameters are about Y4 inch
and fi nish the cut-off with
I
\
a s a w.
The p a r ting tool must
"
be h eld ca r efully to prevent
binding or "hogging-in." FIG. 306
Cutting position of the part
Figure 306 shows the prop ing tool . The point is slightly
I /' I II
FIG. 309 . Con vex Cut or " Bead"
The best convex cuts, or "beads," (Fig. 309) , a re made with
the small skew ch isel. Four stages in t he cutting pr ocess are illus
trated in Figure 310. The first grooving is made exactly t he same
as for a V cut and a t the points whi ch will be t he ends of the bead
(Fig. 310). T hen start the cut from the center of the bead as
shown in Figure 31 1. Hold the blade fairly flat and high enough
on the work so that only the heel will cut. Work th e tool toward
the side ( Fig. 312), and at t h e sam e tim e draw it forward to avoid
cutting the adjacen t stock. As t he g roove b ecomes deeper, keep the
back edge of the blade from spoiling the slope of t he bead.
c«]~p
FI G. 310
I
CUTTIN G A CONCAVE CURVE WITH THE
SMALL GOUGE
FIG. 317
Roughin g out the cur ve. The
to ol is pushed dire ctly into t h e
wo rk wl th a s c rap in g cut.
FI G. 31 8
P r oper to ol position a t end o f
" ro Iling" c ut. T h e ground porlion
o f t he too l is a t a ri g h t an g le to
t he s ide o f th e g roo ve.
:$p
1;: l
I
F IG. 319
T ool positi on at end o f
" rolling" e ut. The cutt ing
has been do ne w it h t h e s ide
lip of the ch isel.
224 MANUAL OF LATHE OPERATION
FIG. 322
Use t h e parting t ool to cut a
groove about Va inch wide and
deep enough to leave a diam
eter of about ~ inch at ea ch
end of the work. As shown at
the left, this groo v e is made by
t a king two separa te cuts wi th
the parting t ool.
FIG. 323
Cut a wide V groove at each end with small skew chisel, hold ing too l
t h e same as f or cutting shoulders (page 223) . Pare off end to correct
dimensions, keeping groove well cut out and clear. Continue cut un t il
di ameter is about 3/ 32" at tailstock and Ys" at headstoc k-be sure en ds
are smooth and clean.
FIG. 324
Cut off the headstock end with the chisel point, catching t h e w ork wi t h
t h e l eft hand as it falls. Cut off the small tailstock end with the skew or
a shar p knife. Some operators prefer to stop the lathe when the groo v e
diameters are about ~ inch and finish the cut-off with a saw.
226 M AN UAL OF LAT H E OPERAT ION
FIG. 329. Usin g chucks made from scr ap st o ck. T ak e light cuts d ur ing these opera tions.
I
[I
I
228 MAN UAL O F LATH E 0 PERATI ON
work, nails v er y well, has m edium strength, and does not warp
badly when handled prop erly. The pith rays are quite noticeable,
but not commonly use d for decorative purposes. The color is
greenish, or yellow b rown. Yellow poplar is a good wood to keep
in stock fo r all sorts of purposes, a nd an ideal wood for carving.
GUM has a beautiful chocolate color, varied with uneven d e
posits of coloring matter. It has an even texture, takes a fine
finish, polishes well; it is comp aratively easy to work, a good wood
for carvin g, and n ails fairly easily. However, gum twists a n d
warps m ore than a n y other common wood. It is often used in
making small arti cles for household use.
BLACK WALNUT is a rather expensive coarse-grained wood,
very easi ly w orked. It is chocolate in color and used very com
monly for fine furniture.
MAHOGANY is a general nam e covering a number of species,
all of w h ich are imported. The diff erent varieties are somewhat
alik e in color, reddis h brown. The annual rings va ry consider
ably in h a r dness, difficul ty of nailin g and shade of color. The
grain is likely to be variable, causing an attractive reflection of
light. Few woods take g lue better than a mahogany.
"
Po --
Z
II::
U
I«
~
232· MANUAL OF LATHE OPERATION
LINEAR MEASURE
1: }~~~e~ y~)..::::::::::::::::
1i.1i yard. . ... . ..... . . . . . . .. . .. .
t ~~~~ .... ... .............. .... iJ:
MEASURES O F LENGTH
MEASURES O F VOLUME
1,000 cubit.: millimeters (m m 3. ) .. c ub ic centimeter ..... em l .
1.000 cubic centimeters cubic decimeter ..... dm'.
1.000 cubic decimeters cubic meter .......... mi.
MEASURES OF CAPACITY
10 milliliters (mI.) ... .... .. . .. . centilit er . ... . ... . .... c1.
MEASURES OF WEIGHT
10 millig rams ( mg. ) . ....... . .. . centigram .. . . . ... . ... eg.
Degrees Degrees
Color
Centigrade Fahrenheit
Degrees Degrees
Color
Centigrade Fahrenheit
Page Page
. . .. . .. 87
- K-
Drill set
Drilling operations 81, 88
Keys, A.S.A. . . 188 table
-L-
-E-
Laminated shims . 20
Facing tool . . . 42
Leveling the lathe . . . ... . .. . . .. 2
~li~ .. . . . U
Fluting .. . 11-12
Machining of various materials Part 4
Gears, back . 10
Metric threads 108
Grinder, bench 38
Milling cutters . 184
Motor recommendations 3
Headstock _' . . . 5
Headstock chuck 75
Headstock spindle 8
-N-
Heat in cutting 31
Heavy cuts . . . . .. 48
National Form threads 98
chucks . . . . . . . 72-77
-0
collet attachment . 78-79
Oak (woodturning) 229
face plate . . . . . 77
Odd-pitch threads 131, 150, 171
mandrel or arbor 79
Oiling lathe 4, 6-7 chart
O verhang, avoiding 35
- 1
Independent chuck 72
-P-
Indexing mechanism 12
Indexing table . . 12
Pine (woodturning) 229
Plaskon, machining 62
-J-
Polishing . . .. . . . .. . 65
J oanite machining 62
Pyralin, machinin g . . 62
tl 0
'" ><
I%:
0
""
Vl
1.:1
CJ
0(
p..
Stand aside before set ting any grinding wheel into
motion. The centrifugal force of a wheel increases
as the square of the velocity.
* * *
When you are through with a tool, return it
immediately to its proper place in as good condition
as when you took it.
* * *
Never withdraw a hand reamer from a hole by
turning it counter-clockwise.
* * *
Never attempt to drive or press a bushing into
a hole if it is possible to draw it into place by
inserting a threaded bolt through the bushing and the
part to be bushed and taking up on a nut at the
opposite end.
* * *
When a milling cutter chatters, try slowing
down the spindle speed. The teeth of the cutter
may be synchronized with the lathe gear teeth at the
speed the spindle is running.
* * *
The cutting edges of reamers may be protected by
wrapping them in several places with gummed tape
before storing.
* * *
If a correctly ground wire drill cuts large, the
first thing to do is to check the concentricity of
the chuck. If there is no trouble there, shorten the
drill 1/4 to 1/2 inch and repoint it.
* * *
An occasional oilstoning of the cutting edges
of a drill or reamer will extend the time between
grinds. Stoned cutting edges also stand more feed
and speed.
* * *
A milling cutter will last much longer between
grinds if the sharpening is finished by taking a
light cut with a freshly dressed wheel and oilstoning
the cutting edges.
Printing and Cerlox Binding
By
IHLlNG BROS. EVERARD CO.
Kalamazoo, Michigan