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East Engin.
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East Engin.
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1222
H681

THE
SCREW- CUTTING LATHE
HOW TO SELECT, SET UP, ADJUST
AND OPERATE
MIC MUNIV
TERRIR
BY JAMES F. HOBART, M.E.
NEW YORK
McGRAW PUBLISHING COMPANY
1907

COPYRIGHTED
1907
By JAMES F. HOBART
TV35
CO
NOUS

'L'E3 86-32-14
GREETING

0
To the young man--particularly the young black-
smith--who is endeavoring to increase his usefulness
this volume is directed, that he may perhaps by its
perusal be enabled to make use of my years of experi-
ence and thereby be able to do more and better work
and increase his usefulness and earning capacity.
JAMES F. HOBART.
Willoughby, Ohio,
June 15, 1907
18001


CONTENTS
CHAPTER I.
Selection of a lathe - The best size of lathe to buy – Selecting a second-hand
lathe — Testing head and tail spindles — Tests for wear in the bed — Tests for
the lead screw What kind of lathe — The overhead countershaft How to use
the lathe....
Pages 7 to 12
--
-
CHAPTER II.
Setting the bed — Erecting the countershaft - Fitting belts — Punching holes and
lacing — Good methods of lacing belts — Proper and improper punch holes — Wire
lacing-Aligning the countershaft...
..Pages 13 to 20
CHAPTER III.
Making lathe ready for use — Setting-up the headstock - Adjusting the spindle
bearings — Putting centers in line - Moving the tail-center - Truing up, hardening
and grinding centers -- Adjusting the slide rest — Setting gibs — Adjustment of
spindles. ...
..Pages 21 to 27

CHAPTER IV.
Putting work into the lathe Centering work in the screw-cutting lathe — Truing
centers — Straightening and squaring-up work - The steady-rest and its use - The
back-rest - The back gear and its use...
...Pages 28 to 34
-
-
CHAPTER V.
The tool post and its use Proper position of cutting tool — Collar and wedge
adjustment Clearance and rake of tool -- Forms of simple lathe tools — Proper
setting of lathe tools — Methods of using different tools — Boring and inside cuts
Setting work for finishing or roughing cuts...
Pages 35 to 43
-
CHAPTER VI.
Depth of cut - The proper speed Lathe step cones and back gear — Diameters
of work giving twenty feet a minute velocity - Tendency of modern practice toward
high speeds for turning-Roughing and finishing cuts—Water cuts-Use of soda-
water and of oil...
Pages 44 to 50
CHAPTER VII.
Filing work in the lathe - How to hold a file Picking a file — Emery cloth
and its use — Grinding with emery wheels - Keeping emery wheels in order — Tool
post, overhead grinding rig — Truing emery wheels — Selecting a diamond tool for
truing wheels—Buffing and polishing—Danger of lathe grinding.... Pages 51 to 57

-
screw -
-
CHAPTER VIII.
Screw cutting — Spindle stud and lead
Calculating change gears
Simple and compound change gears - Gears for cutting right-hand threads — Gears for
cutting left-hand threads -- Compound change gears Box change gears -
Modern
box gear arrangement Shape of thread-cutting tools -- U. S. Standard, and Stand-
ard V threads - The Whitworth thread — The square thread and Powell thread —
Taking roughing and finishing thread cuts Catching threads vs. running the carriage
back...
.Pages 58 to 68
-
CHAPTER IX.
Internal turning or boring — Uses of the chuck and the steady rest — Clearance
of boring tools-Putting on a chuck—Accurate centering—Centering indicator
Setting the steady rest for boring — The boring bar and its use - The chucking drill
boring bar Proper setting of boring tools — Cutting internal threads — Reaming in
the lathe. ...
Pages 69 to 78
-
-
(5)

6
CONTENTS.
CHAPTER X.
The face-plate Chucking work in the lathe — Chucking a pulley—Chucks vs.
face plates — The independent chuck Chucking with wooden shapes — Chucking with
wax....
... Pages 79 to 87
-
-
-
CHAPTER XI.
Boring in the lathe - Boring small cylinders — Mounting a cylinder - Cylinder
mounted on slide rest — Centering the cylinder - The calipering — Bad and good
calipering -Chucking work with plaster-Tools and jigs.. ... Pages 88 to 98
CHAPTER XII.
Turning wood in the iron working lathe — Inside and outside turning tools for
slide rest wood turning — Turning up patterns — Chucks and centers Labor-saving
jigs and attachments — Other tools to be added with profit........ Pages 99 to 109
-
-
CHAPTER XIII.
Making a quarter-turn crank shaft Good and bad forgings — Crank-shaft jigs
Use a surface plate — Laying out a shaft Surface gage - Drilling crank centers
- Roughing out and finishing - Steady pieces...
Pages 110 to 118
-
-
CHAPTER XIV.
Milling in the lathe Apparatus necessary Dividing head
Ancient index plate — Modern dividing head
- Milling slide rest
Pages 110 to 127
CHAPTER XV.
Specializing vs. generalizing - Making drawings - Designing an eyebolt - Factor
—
—
of safety — Designing a casting - Reference books - Pattern work and molding
"Draft" in patterns — Castings broken by poor designing....... Pages 128 to 135
-
-
CHAPTER XVI.
Speeding a circular saw Making a pulley Size of set-screws Thickness of
flange — Split patterns Cored holes Corners on patterns Painting patterns
Boring the hub....
.Pages 136 to 144
-
--
CHAPTER XVII.
Shafts, pulleys and belts Width of belts Cost of pulleys and belts Slipping
belts — Belt adhesion — Belt splicing — Belt lacings -- Quality of belts.. Pages 145 to 156
-
-
CHAPTER XVIII,
Threading pipes in the lathe — Dimensions of steam, water and gas pipes -- Size
of pipes — Special pipe tail-centers — Cutting-off and chucking — Cutting a taper
thread — Taper-thread dial - Threading pipes longer than the lathe - Internal pipe
drive...
..Pages 144 to 160

THE SCREW-CUTTING LATHE.
CHAPTER I.
SELECTION OF A LATHE.
Hardly a day passes but the progressive smith sees oppor-
tunity for increased profit if his shop contained some appliance
for doing a little machine work. Particularly is this the case
when automobile work is to be done, but in the ordinary run
of custom work there are numberless opportunities for work
which has to be “sent to the machine shop” because there is
no machine in the smithy which can be made to turn up a
journal bearing or face up a collar or a flange. There are also
numerous opportunities for making work when a good lathe is
at hand, and the smith who once has a good tool of this kind
in his shop will never again be without one.
The smith who has an idea of putting in a screw-cutting
lathe should lose no more time thinking over the matter. Secure
the lathe at once, and then begin to be sorry—that it was not
secured long before. The worst question the smith is called upon
to decide is “What size of lathe is it best to purchase?” This
is a very hard question to decide, for no matter what size of lathe
is purchased there will come a time when it is entirely too small.
Next, the time comes when the lathe is entirely too large for the
work that should be done upon it.

THE BEST SIZE OF LATHE TO BUY.
Probably the size of lathe which will give the most universal
satisfaction to the smiths has a bed seven or eight feet long and
will take a length of four feet between centers. That is a piece
of iron four feet long can be put between the two centers. The
lathe should swing at least sixteen inches. This means that a
pulley on a short shaft can be put in the lathe as long as the pul-
ley diameter does not exceed sixteen inches or the length of the
7

8
THE SCREW-CUTTING LATHE.
shaft exceed forty-eight inches. But this does not mean that
the 16-inch pulley will let the slide-rest pass under it. No object
much larger than eight inches in diameter can pass the slide-rest,
consequently the lathe man describes that particular size as
"swings 48 inches between centers, 16 inches over shears and 8
inches over saddle.” These dimensions represent the limit of
work that can be put into a lathe of that size, and the smith
should keep his eye open for some time in regard to the pos-
sible lengths and diameters of work he expects to handle in the
new lathe. However, for the general run of smithy work a
lathe of the above-named dimensions should answer very well.
There are numberless makeshifts for doing large work in
a small lathe, and the writer well remembers the wooden blocks
to put under the head and tail-stock when larger work than the
lathe would swing had to be done. And there was also the
wooden extension which was bolted to the end of the lathe-bed
to carry the tail-stock when something three feet or so longer
than the lathe bed had to be put between centers. There is
almost no limit to the capacity of a small lathe for large work,
therefore select a lathe which is very strong and which will
stand the severe demands sure to be made upon it. Pay no at-
tention to a fancy lathe. Put every cent of the money you have
to spend into strong, well-fitted spindles, good head and tail-
stocks and a heavy well-fitting slide-rest on substantial Vs of a
well-proportioned lathe bed. Then there will be little danger of
making a wrong selection of a lathe.
SELECTING A SECOND-HAND LATHE.
The writer would always advise the smith to buy a new
lathe if possible, but there are sometimes circumstances which
forbid the new tool while a second-hand one may be in sight.
There are many excellent second-hand lathes, but it requires
a man accustomed to lathes to pick out a good one. There are
a few simple things to be looked at which will prevent the smith
from selecting a lathe which has been too badly worn. First,
look over the entire machine for signs of wear and hard usage
If the bed has been hammered, and Vs all dented and jammed up,
the tool-post hammered out of shape, the gears broken or worn
thin, then the smith may well leave that lathe to the junk man
and pass to the next tool.
THE SCREW-CUTTING LATHE.
9

Next, if there are not signs of excessive wear and abuse
as above noted, look to the condition of the spindle. See if it
has gotten out of center, sidewise or vertically, even to the slight-
est degree. This point may usually be determined pretty closely
by looking at the front end of the spindle where it leaves the
bearings. If there be the slightest appearance of eccentricity be-
tween the spindle and the ends of the bearings, then it is safe
to assume that the bearings of the spindle, or both have become
worn too much to permit of good work until the lathe has been
overhauled in the machine shop.
TESTING HEAD AND TAIL-SPINDLES.

a
Put a bit of plank under the end of the spindle, run the slide-
rest up to the head-stock and take a pry over the slide-rest with
the plank. If there be any lost motion between the spindle and
its bearing, the fact can be readily determined by the movement
of the spindle when force is applied to the bit of plank.
The same test may be applied to the tail-spindle to find
if it be considerably worn. At the same time the spindles, both
head and tail, should be so adjusted that they both move easily
and freely in their respective housings. The cones of head-
spindle and clamp of tail-spindle can be so closely adjusted that
the “pry-test” above described will reveal nothing, even though
the wear may have been considerable.
have been considerable. The condition of the lathe
for this test must be normal and exactly as for actual work.
The condition of the slide-rest and its movement upon the
Vs of the lathe bed should next receive attention. There is
danger that the lathe bed may have been worn near the head-
stock, as, owing to the fact that a large proportion of the entire
work done on a lathe is very short, the Vs become worn down
just at the front end of the head-stock and the lathe becomes
of very little use for long work.

TESTS FOR WEAR IN THE BED.
A good test for wear of the Vs is a very accurate short
straight-edge laid upon the Vs between the head-stock and the
tail-stock in its farthest position. Hold the straight-edge in place
by means of two weights, one at either end. Place a piece of
paper between straight-edge and V, and move paper along to
see if it be pinched as much in one place as in another. Some

IO
THE SCREW-CUTTING LATHE.
old lathes show one-sixteenth inch vertical wear in the top of the
front V, which wears much faster than the back V. But vertical
wear alone does not always prevent a lathe from doing a fair
job of straight turning. It is the lateral wear of the Vs, and
this must be tested also by putting a tool in the post on the slide-
rest and then clamping the straight-edge flat upon its side paral-
lel to the lathe bed in such a manner that the tool will just pinch
a piece of paper laid against the straight-edge between it and the
tool.
With the straight-edge clamped as described, move the slide-
rest from one end of its travel to the other, testing continually
with the piece of paper between the straight-edge and the fixed
tool. If the paper is as tight at one place as another the Vs are
evidently in first-class condition, but if, as is pretty apt to be the
case, the paper is loose most of the way and tight only in one or
,
two spots, then the smith may well squint sidewise at the lathe
in question and say: “To the shop for yours, another lathe for
mine." If any second-hand lathe passes the above tests, then
it is worth taking slightly apart so as to see the condition of the
bearings in the cones and on the spindles. The apron should
also be overhauled a little to see that there is nothing broken
there. See that the wear in the apron is not too great. This
can be done by noting how far it is necessary to turn the handle
one way or the other in order to start the slide-rest amoving
in one direction or the other. If not over one-sixth of a turn
is necessary the lathe is in not very bad condition in that direc-
TESTS FOR THE LEAD-SCREWS.
Close the nut upon the lead-screw and repeat the same test
to see how badly the nut is worn. Probably the handle will move
farther in either direction in this test than it did before the slide-
rest commenced to move in the last test. The difference in
movement of the handle is due to the wear of the lead-screw
nut. The actual movement of the slide-rest is the amount of
wear in the nut. If this movement is one-sixteenth inch or over
a new nut will be required. Make this test in different parts
of the lead-screw. If the lost motion of the rest is the same at
all points a new nut will cure the trouble, but if the motion
varies the screw itself is badly worn and the smith had best pass
along to another and less ancient lathe.

THE SCREW-CUTTING LATHE.
II
The smith may not have determined fully just what kind of
a lathe he ought to purchase and it is by no means clear to him
what kind is the most desirable for the work he expects to do.
From the points noted above the smith will be pretty apt to
select a new lathe or one which has been thrown on the market
when nearly new, by some cause other than the lathe being in any
manner defective. But such bargains are usually scarce and not
always to be depended upon, while the new lathe is always in
evidence and a sure bargain.
WHAT KIND OF LATHE.
But as to the kind of lathe to buy: By all means pur-
chase a back-geared, screw-cutting lathe with both rack and
screw feeds, reverse motion in the head-stock-or somewhere
else, as in some makes of lathe, and see that the lathe has a hol-
low spindle in the head-stock and a split clamp in the tail-stock.
See also that the tail-stock has ample provision for being offset
sidewise for the purpose of turning taper shapes. The step-cone
in the head-stock should have at least four steps for the belt
and the step-cone should be fastened to the main gear by means
of a bolt, which merely slips in and out of gear sidewise when
the change in gear is to be made.
Do not select an old-fashioned lathe in which the bolt takes
out entirely when the back gear is to be put into mesh. The nut
for the screw alongside the lathe (the lead-screw) should also
be examined to see that the nut is split and is operated by a cam.
Some old-time lathes have a solid nut which has to be attached to
the slide-rest by means of a bolt or two every time a screw thread
is to be cut. Don't look but once at a lathe of this kind.
See that there is plenty of metal in the bed of the lathe. A
weak, thin bed which will spring out of shape under the strain
of a heavy cut is not at all desirable. Most lathes have heavy
beds, but the smith knows not what he will be "up against" when
he gets into the market, therefore, “watch out.”

THE OVERHEAD COUNTERSHAFT.
The overhead countershaft also needs looking after. There
should be upon that shaft, together with the step pulley to match
the pulley on lathe, a pair of friction clutches for stopping or
starting the go-ahead and the backing-up motions. The lathe

12
THE SCREW-CUTTING LATHE.
countershaft must be connected with the pulleys on the main
shaft by means of two belts, one open, the other crossed, and
it is not at all desirable that these belts be connected with the
lathe countershaft by means of either tight and loose pulleys,
jaw clutches, or dogs on the countershaft which can be made to
engage with either one of the pulleys mentioned above. Insist
upon a pair of friction pulleys, and that, too, upon cone frictions
the engaging surfaces of which are plain cast iron and entirely
free from all surfaces of paper, wood, leather or other sub-
stances. Plain cast-iron cones are the things for lathe counter-
shaft frictions—and they are most excellent for other friction
pulleys, too.
HOW TO USE THE LATHE.
This will be the question fired in by very many readers who
have just bought lathes and wish to learn just how to use them
to the best advantage. To see a machinist stand and watch a
nice sharp tool cut a nice clean shaving and leave the work
smooth and of just the right diameter required is a quite dif-
ferent thing from what happened when the first piece of work
was put into your lathe! To be sure, you made the centers
with a prick-punch, and were not very particular as to what
kind of tool was put in the tool-post, or just how that tool was
set. No wonder that the bit of iron you wished to make into
a nice pin persistently refused to become either round, straight
or of the desired diameter. Never mind, these things will all be
taken care of in proper order, but there are an awful lot of such
things to be looked after, and as yet we have not even gotten the
lathe set up and leveled properly. And then there is the lathe
bed to get "out of wind.” The size of pulleys on main shaft
must be determined to make the lathe run at the right speed, then
the countershaft must be fastened up, the belts laced properly
and then the lathe must be made ready for use.
The centers must be trued up and put in line, perhaps the
tail-center will need hardening and grinding, and surely the
head and tail spindles must be properly adjusted, the slide-rest
oiled and adjusted and other things looked to. Do lathe work
now? Might as well try to weld before a fire has been built in
the forge.

CHAPTER II.
SETTING THE BED.
A lathe usually comes into the shop mounted on skids, which
are merely two pieces of plank or joists a little longer than the
lathe bed and fastened to the feet of the lathe by means of four
lag screws. Such cross bracing as may be found necessary con-
nects the two skids. Do not remove the skids until the lathe has
been moved on small rollers or short pieces of pipe to almost the
exact spot it is to occupy. The countershaft will probably be
found fastened to the skids, together with one or more boxes
containing the loose pieces of the lathe, together with the easily
removable small parts, such as the various handles, tool post,
wrenches, etc.
Having determined the exact spot where the lathe is to stand,
stretch a string or chalk line parallel to the main shaft and high
enough above the floor to let the lathe pass under the line, then
bring the lathe into place under the line, take off the skids and let
the legs down carefully upon the floor. It is best to use a small
timber as a lever for this purpose, taking a pry under the bed
of the lathe, and taking great care not to damage any of the screws
or the rack, or to drop the lathe legs upon the floor. Do not let
it drop even to the extent of an inch. Having gotten the skids
.
off, and the lathe upon the floor, use a spirit level to make the bed
of the lathe exactly level, both lengthwise and crosswise the bed.
It is
very seldom that the floor is so perfectly level that the four
legs of the lathe will have an equal bearing, therefore it is nec-
essary to “shim up” under the feet of the lathe as may be found
necessary to make each foot bear evenly upon the floor. While
the shimming and leveling is being done the lathe must be ex-
actly in the place where it is to stand.
It is good practice to suspend a plumb-bob or a small weight
on a string from the tong line above mentioned at either end of
the lathe and to bring the ends of the spindles exactly in line with
the plumb lines. Lag screws had better be put through two of the
lathe feet and the screws left sticking up an inch to allow of the

13

14
THE SCREW-CUTTING LATHE.
necessary wedging under the feet. In this manner the lathe will
be kept in line until the feet have been temporarily wedged up and
permanent pieces fitted under each foot in place of the wedges,
after which the lathe may be screwed down permanently. It is
well to take a little time and make a good job of the above work.
Although any good lathe should be so designed that it will do good
work with the bed supported at opposite diagonal corners, there
but
very few lathes which will not give better results when per-
fectly bedded upon a good solid foundation and perfectly leveled
and aligned with the main shaft of the shop or with the engine.
are
THE COUNTERSHAFT.
This is usually a piece of shafting 11/2 inches in diameter by
3 feet to 3 feet 6 inches long, with a pair of drop hangers for at-
taching shaft to ceiling overhead. There is also a pair of crown
face pulleys on the shaft which normally run loose, but either of
which may be rigidly connected with the shaft at will by the move-
ment of a lever in one direction or the other. One of these pul-
leys is known as the "go-ahead” pulley, the other as the "reverse"
or “hacking” pulley.
Attached to each lathe should be printed directions stating the
speed at which the countershaft should run, and in erecting the
shaft, care should be taken to obtain pulleys for the main shaft
which will give the required speed. For instance: If the coun-
ter is to run at 150 revolutions per minute and the main shaft runs
at 200 revolutions (in all future chapters the speed of a shaft or
machine will be stated thus: 200 RPM., meaning 200 revolutions
per minute), with pulleys 16 inches in diameter on the counter-
shaft, what diameter of pulleys on main shaft will give the coun-
ter a speed of 150 RPM.?
It is best to state all these examples in a simple fraction-pro-
portion form, as follows:
Speed of driving pulley X dia. of drive pulley.
Diameter of driven pulley X speed of driven pulley.
Substituting the numbers, it becomes : 200 = 16 X 150 =12,
the diameter of the pulley required on main shaft to drive the
countershaft at 150 RPM., the answer may be found by multi-
plying together the numbers below the line and dividing the re-
sult by the number above the line, or cancellation may be used.
a

THE SCREW-CUTTING LATHE.
15
It makes no difference how many countershafts or pulleys it is de-
sired to calculate speed through. Just put them all in line as
above, with the speed of first shaft and the diameter of all driving
pulleys on top of the line and put diameters of all driven pulleys
below the line, then cancel or multiply and divide clear through
and the resulting number will be the diameter of pulley or the
speed of shaft required, as the case may be.
FITTING THE BELTS.
Having put the countershaft in place, leveled it carefully and
carefully aligned it to the main shaft, the belts may be put on
as follows: Run a tape measure or a string which does not stretch
around a pair of pulleys, taking care to pass the tape on either of
the edges or in the middle of both pulleys—it matters not which
as long as the tape does not run criss-cross from side to side of the
pulleys—then carefully note the length of the belt required. If the
tape calls for 16 feet 6 inches of belt, then actually cut the leather
2 1-16 inches short of the tape measurement. Allow 18 inch per
foot of belt is the usual rule, and it comes out pretty close.
Three belts will be required for the lathe; one from the
stepped cone to the countershaft and two belts from counter to
main shaft. One of this pair of belts must be crossed, the other
must be open. In some lathe arrangements the "backing” pul-
"
ley is smaller than the "go-ahead” pulley in order that in screw
cutting the carriage may return the tool for a new cut faster than
is permissible in the cutting movement itself. But in the more
modern lathes the carriage is usually run back by hand,"catch-
ing” the thread at the proper instant, as will be described later.
This allows both countershaft pulleys to be made of the same size,
hence the "backing” belt may be placed on either, as desired. It
will be found that the crossed belt requires a little more leather
than the open belt, owing to the diagonal position of the folds.
PUNCHING HOLES AND LACING.
Once the proper length of belt has been determined, cut the
ends of the belt off square, using a carpenter's try-square for
marking the leather-do not try to guess at the squareness of the
cut. It pays to mark the belt as directed and then cut the leather
cleanly with a very thin, sharp knife. A "belt box” should be es-
tablished at once, and in that box should be kept all the tools nec-

16
THE SCREW-CUTTING LATHE.
essary for mending or splicing belts. Have a cover to the box,
for rats dearly love to chew up good belt lacing. Buy a “shoe
knife” for ten cents and put it in the belt box, and under no cir-
xxyy
OUTSIDE
,FINISH
HH H
START
PULLEY SIDE
Fig. 14Good Method of Lacing Belt.
cumstances whatever are that knife or the other tools in the box to
be used for other work than lacing belts.
There are innumerable ways of lacing belts, and perhaps many
ways as good as those shown here, but belts laced by either method
will give perfect satisfaction in any shop. The first method,
shown by Fig. 1, is a good form of ordinary lacing where the ends

THE SCREW-CUTTING LATHE.
17
of the belt are joined with a narrow strip of rawhide. For any
belt likely to be used in a smith shop a lacing should never be cut
more than 38 inch wide. It is better 5-16 inch wide. The lacing
should always be narrow and the holes small. A number of large
holes punched through a belt weakens it very much and such
holes should be avoided. Take a 4-inch belt and punch 38-inch
holes across the end. The man who does this without a thor-
ough understanding of the matter will usually punch four holes
in a row, somewhat as shown by Fig. 2 at A, where the holes are
А
B
Fig. 2- Improper and Proper Punch Holes.
punched as described above. At B is shown a much better lay-
out and the value of the two methods is as follows: In sketch A,
4 X 38 inch of belt has been cut out of 4 inches, leaving 212
inches, or 627/2 per cent of the belt at the splice to do the work
of the rest of the 4-inch belt. In case of the belt holes shown
by sketch B, the five 3-16 inch holes, cut 15-16 inch from the belt,
leaving 3 1-16 inch or 767/2 per cent. of leather.
There is also another point to be considered. If we were
calculating the strength of strap iron or boiler plate the above-
noted method would be sufficient, but belts do not break square
across from hole to hole as at a and b, Fig. 2, sketch A. Instead
of this the leather will tear at an agle of about forty-five degrees,
as shown at c and d. Taking this view of the case, there are ten

18
THE SCREW-CUTTING LATHE.
pieces of belt in B to be torn, against eight in A, therefore the
strength of the two belts is as 10 to 8, or as 5 to 4. By a glance
at sketch A it will be seen that the tearing at c comes to a point
before it reaches the edge of the belt. This tells that it is un-
START AND
FINISH
ll!
OUTSIDE
E
PULLEY SIDE
Fig. 3-Excellent Wire Lacing.
necessary to have so great a distance between the row of holes and
the end of the belt. It also tells that the more holes and the
smaller in diameter the stronger will be the belt splice or joint.
In Fig. 1 the lacing is shown as beginning and ending at the
middle of the belt. This should always be done. An awl hole
should be made, the lacing forced through, and a knife cut made

THE SCREW-CUTTING LATHE.
19
in the edge of the lacing about one-third across, close to the sur-
face of the belt, then the lacing should be cut off 38 or 1/2 inch
longer, and the ends left hanging on the side of belt next to the
pulley. Such a lace fastening will never slip if properly made.
The front and pulley sides of the belt are shown, and the lacing
should be disposed as shown, with no crossing of the strands on
the pulley side of the belt, otherwise the lacing will cut quickly.
Fig. 3 shows a most excellent form of belt splice for lathes
3
and general machine-shop work. The wire is made specially for
the purpose and is very strong and flexible. It can be purchased
in small coils in little boxes, all ready for use. When the holes
с
a
D
a
Fig. 4-Aligning Shafting.
are punched with an awl no belt material will be removed, there-
fore there is 100 per cent. of belt strength at the joint, and sixteen
strips of tearing to be done before the splice can be pulled apart,
hence the great strength of a splice of this kind. It will be seen
that there is no crossing of wires on the inside or pulley side of
the belt, otherwise the wires would quickly cut each other in two.
The ends of the wire are twisted together in the middle of the belt.
One thing more must be done or the splice will be worthless: the
wires must be hammered into the belt so as to be even with or
below the surface thereof, otherwise the splice will not last long.
Put the splice on an iron pulley and hammer it well but lightly,
taking care not to let the wires cut the belt, only to sink into the
leather.
ALIGNING THE COUNTERSHAFT.
Some people make a great deal of hard work about a very
simple operation, notably in aligning shafting. The whole thing
is shown in a nutshell by Fig. 4. Just hang two plumb-bobs on

20
THE SCREW-CUTTING LATHE.
the same side of main shaft at G and B; then place a square pointed
stick against the counter at C, and mark at a, the bob-line. Carry
the same stick to D, and if the bob-line touches the mark a the
shafts are in line. If not, as shown in the drawing, move the
shaft until they coincide. Test both at C and D at least twice each.

CHAPTER III.
MAKING READY FOR USE.
The belts having been put in place, see that they all run fair
upon the several pulleys. Usually pulleys are made about half
an inch wider than the belts that should run upon them and
if
aniy belt seeks to run over the edge of a pulley, then there is
something wrong with the aligning and levelling of the lathe
or shaft. Look for and cure the trouble before going farther.
Never, under any circumstances, be guilty of the unmechanical
trick of nailing up a piece of board to guide the belt and to
keep it on the pulley. Sometimes there may be a crooked place
in the belt which should be cut out, but otherwise, unless the
pulleys themselves are badly turned and left conical on their
faces, the trouble is surely in not setting the pulleys square and
level with each other.
Put some oil in the spindle bearings—we will adjust them
later-and start the lathe to running. See that the belts all run
fair, "track," they call it, with no tendency to seek either edge
of any pulley, then see that the same thing happens with the
belt between the step pulleys on lathe and counter. Sometimes
a slight movement of the lathe endwise is necessary to make
the belt run fair, but run fair it must, without chafing against
the higher steps of the cone or running over the edge of any
step.
“SETTING-UP” THE HEADSTOCK.
At this stage of the game it is well for the "smith-machinist”
to become thoroughly familiar with the construction of the lathe,
with the various mechanical movements contained in the head-
stock and slide rest, and to this end it is necessary to take down
the lathe to a considerable extent. But right here, a word of
warning: Don't take down the whole lathe at the same time.
Investigate a bit at a time. If the entire lathe be taken down
there will be a hopeless mix-up of parts and something will
surely be broken or damaged. Instead of wholesale dismember-
21

22
THE SCREW-CUTTING LATHE.
ment, take down only a small portion at a time as in the present
instance, only the main bearing will be investigated.
Take off the belt by giving it a flirt with the hand while the
lathe is running. The particular knack of throwing a lathe belt
off and on the cone pulleys must be studied and practiced until
it can be done the first time trying. There is a “knack” about
it, that's all. By a little practice, a belt can be snapped from each
smaller step on the upper pulley to the next larger step until the
largest one is reached. To do it the belt is run on to the smallest
lower step with one hand while with the other hand the “going
up” fold of the belt is so guided that it cannot run off upon the
next smaller step of the upper pulley. Then with a quick snap
the belt is jerked sidewise with a twist which flips it neatly upon
the next larger step of upper pulley. This trick can only be
learned by practice—and lots of it.
Take down the main bearing of the spindle—the bearing
next to the body of the lathe—and note well the manner in which
the bearing is arranged so that wear can be taken up. Note
well also the adjustment provided for taking up wear and for
keeping the bearing tight and well fitting. Usually the front
bearing is a cone while the other bearing is straight. Sometimes
both bearings are cone or taper, but not in the best lathes.
ADJUSTING THE SPINDLE BEARINGS.
.
See that the bearings are free from grit or other dirt, and
study well the method of adjusting the cone. After replacing
the caps, adjust the take-up screw in such a manner that the
bearing will run easily but without the least lost motion. As
the spindle should be hollow, the screw at end of headstock
should be hollow also, and quite a large check-nut is nec-
essary to hold the screw after it has been adjusted. Usually
the setting up of the check-nut will be enough to loosen the cone
enough to let it shake a trifle, therefore this point must be looked
to by setting the screw a trifle too tight and then the check-nut
will slack it just enough to bring the spindle free but tight.
PUTTING THE CENTERS IN LINE.
A lathe as it comes from the shop is supposed to have the
centers in exact alignment, but this supposition cannot be
trusted. The fact must be shown, and every time the lathe is

THE SCREW-CUTTING LATHE.
23
used on an extra nice piece of work it is necessary to apply the
test which is as follows: Select a piece of shafting or round iron
or steel between one and three inches in diameter and as long
as will go easily between the lathe centers.
Put a sharp tool in the tool post and adjust until the cutting
point is exactly as high as the points of the lathe centers. Take
a cut over an inch or two of both ends of the test bar, as we will
call it. Commencing the cut next to the tail center, and revers-
ing the test piece in the lathe to cut the other end. Both roughing
cuts having been made, sharpen the tool and take another light
cut (as smooth as possible) on the end of test piece next to tail
spindle. Cut only about one inch in length, then, without mov-
ing the tool in the least, remove the test piece from the lathe, after
which carefully run the carriage back so the tool will be close to
the tail-center, but be sure not to move the tool itself, either to
or from the work by means of the cross-feed screw, which must
not be touched at all during the operation.
Reverse the dog on the test piece and replace in the lathe,
then make a finishing cut on the other end of the test piece with-
out altering the position of the tool in the least except as the feed
moves it along the lathe bed. Having completed the finishing cut,
remove the dog from the work, adjust nicely between centers
so there will be no play whatever, then without altering in the
least the vertical position of the lathe tool, run that useful appli-
ance forward by means of the cross-feed screw until the tool
barely touches the piece of metal between the lathe centers.
While the above-noted action is taking place, move the slide
rest lengthwise of the lathe an inch or so, and keep the carriage
reciprocating back and forth while the tool is being forced very
slowly toward the piece between centers. When as above, the
tool barely touches the work, leave the tool in that position
and move the carriage on the lathe so that the tool marks a very
fine straight line along the work. Without moving the cross
feed, or touching the tool, remove the work from the lathe and
run the carriage ahead until the tool is close to the head-center.
While the tool is in that position replace the work between centers,
adjusting them exactly as before, and proceed to mark a line on
the turned portion of the shaft next to the head-center.
It is ten to one that either the tool will not touch the shaft
at all, or that it will want to make a very deep mark. In either

24
THE SCREW-CUTTING LATHE.
case, the lathe centers are out of line with the lathe bed and if
the shaft be turned from one end to the other, it will come from
the lathe cone-shaped instead of a true cylinder.
MOVING THE TAIL-CENTER.
The tail-center is so arranged that it may be moved laterally
by unclamping from the lathe bed and then backing up one
screw and tightening another. This adjustment should be made
and the line-marking repeated as above described, taking care to
always set the tail spindle mark last. That is, the mark should
be first made on the end of shaft at head end of lathe and the
other test made at the tail-center whereupon the necessary adjust-
ment may be made at once, which would not be the case if the
mark were made first on tail-center end of shaft between lathe
centers. A slight taper may readily be turned in any lathe by
setting over the tail-stock so that one side of the required cone
will come parallel with the lathe bed. It is partly for the reason
that the tail-stock is liable to be set over at any time that the above
described test is necessary before any turning requiring precision
is to be commenced.
After the centers have been centrally adjusted, a mark is
usually made on the tail-stock by the maker of the lathe. Although
this mark may be used for setting the centers for ordinary work,
it should not be depended upon for close work, and the centers
should be tested as above for every important setting of the lathe.
At least three tests at each end of the lathe should be made to
get an exact setting of the centers. This is necessary for the
reason that when one end of the short shaft is moved by screwing
over the tail-center, the line-drawing tool is thrown out of truth
with the line first drawn, hence the many tests necessary to
bring the two ends of the shaft between centers perfectly parallel
with the marking tool.
TRUING UP, HARDENING AND GRINDING.
Both the centers, the tail-center especially, are apt to become
worn by use and must be put in shape, as often as they depart
from a true cone shape of 60 degrees. A good way to make a
center gauge is to make a notch in the edge of a thin piece of
steel with a three-cornered file. Harden the steel if desired and
shape the centers to the notch, which will be found to be pretty
close to 60 degrees.


THE SCREW-CUTTING LATHE.
25
a
Only the tail-center should be hardened. The head-center is
always left soft. The best way to true lathe centers is by means
of a little emery grinder made especially for the work, and which
can be attached to the slide rest or put in the tool post, and
the head-center ground to shape in a very short time. The tail-
center is ground by placing it in the head spindle for that purpose,
after which it is returned to its proper position. With the center
grinder there is no need of taking the temper out of the tail-
center, but as we have no grinder the center must be annealed
and slipped into the head spindle and given a blow to hold it in
place.
Right here let me state that a hammer must never be touched
to the lathe under any circumstances whatever. Get a copper
hammer or one with a rawhide face, or cast one of lead or babbitt
metal, and such a hammer must always be found among the lathe
tools. If no hammer of soft metal is yet at hand, use a piece of
wood and drive the center home with that. If the lathe has a
compound slide-rest, set the upper screw to 60 degrees and turn
the center by feeding the tool with that screw, by hand, of course.
If there is no compound rest, set the side of a cutting tool to
the angle desired—60 degrees—and feed the tool into a short bit
of the center, deep enough to remove any places that must come
out. Then move the tool along an eighth of an inch by means of
the main and cross feeds and run in another short cut as deep
as the first. Continue this until the center has been turned from

60°
Fig. 5-Center Gage.
Turning a Center.
point to heel, then the use of a file and the gauge above described
will soon bring the center to a proper condition for use. Fig. 5
gives an idea of this operation.
The tail center should then be hardened and the smith will
need no instructions for that job, except that he harden and
draw in the usual manner, leaving only the point of the tool
hardened. A center is very apt to spring during the hardening
operation, and this is one reason why it is necessary to test the

26
THE SCREW-CUTTING LATHE.
lathe for truth of centers every time a nice job is to be done
between centers.
ADJUSTING THE SLIDE REST.
The next step in the lathe adjustment is the slide rest. It
will be assumed that the various parts have been put in place,
the handles put on the feed screws, and everything ready for
use as far as the "smith-machinist” can see. To adjust the rest,
see that the clips which hold the carriage to the ways of the lathe
are so adjusted that the carriage moves freely when the proper
handle is turned, but that there is not the least shake possible
between carriage and lathe bed. The clips must be adjusted very
close and kept well oiled and clean so that with the hardest
possible work being done by a tool, there will be no shake or
tremble between slide and bed as the former moves along the
latter. This point is very essential and should be closely looked
after.
SETTING GIBS.
Next, adjust the cross slides so that there can be no shake
to the tool post. Underneath the cross-feed slide will be found
one or more pieces of steel which are placed between the slides of
carriage and cross feed. Several screws keep in place each strip
of metal which is called a “gib,” and which should be so adjusted
by means of the screws that the tool post can be screwed from
one end of its travel to the other, without going easy in one place
and hard in another. This, as well as every moving or sliding
part of the lathe, should be kept clean and well oiled at all
times.
ADJUSTMENT OF SPINDLES.
The proper method of adjusting the head or live spindle
of the lathe was described at the beginning of this chapter. The
tail, or dead spindle, does not require as much adjustment, yet
it should at all times receive care and oil, and should always be
kept clean. To remove the tail center, screw the spindle back as
far as possible and the inner end of center is forced against end
of tail-stock screw, forcing the center from its seat. In some
operations, tools will be fitted to the tail stock and it should be
kept in mind that all such tools are to be so fitted that they may
be readily removed by backing them against the end of screw as
above described.

THE SCREW-CUTTING LATHE.
27
The tail spindle should be clamped by closing together, by
means of a screw, the front portion of the tail stock. The lathe
possessing a set screw in the tail stock for clamping the spindle
is an antiquated affair and should not be in the possession of the
smith-machinist. The tail spindle should be kept well oiled and
very clean. When the lathe is in operation the tail spindle should
be allowed to project as little as possible. Sometimes it is
necessary to work with the tail spindle projecting a considerable
distance, but whenever it is possible keep it within a half an
inch or so of its most retracted position, for it is then in the most
solid position possible and will stand much harder work
without springing than when screwed out several inches.


CHAPTER IV.
PUTTING WORK INTO THE LATHE.
Don't try to get ahead too fast in running that new lathe of
yours. If you are not accustomed to using a lathe, better follow
the instructions closely and do not attempt to go in over your
head before you can swim. You tried it once, when the lathe
first came into the shop, and you were not at all satisfied with
the result. It was something like this: As soon as the belt was
on the lathe, you picked up the first piece of iron that came to
hand and put it in the lathe. You hit each end of the iron with
a center-punch, as near the center as possible, something as
shown at A and B, Fig. 6. Then, after marking in that manner
both ends of the iron, it was balanced between centers and the
B
Fig. 6-Centering Work in the Screw-cutting Lathe.
.
lathe started on taking a cut along the iron. But you found
it didn't work. The iron soon flew out of the lathe altogether
and you then found the head-center to be pretty well out of shape.
The above is a sample of what happens when work is put
between centers without being properly prepared. The right way
is as follows: Mark both ends of the piece of metal as at A and B,
Fig. 6; then put between the lathe centers and set them up against
the work very lightly, so the work may revolve freely when turned
by hand-simply rolled around by pressure of the hand, the
lathe remaining at rest. Revolve the work slowly by hand as
stated, and hold a bit of chalk close to the work as shown at C.
Rest the chalk against the tool post, or otherwise steady it and
press forward until the chalk touches the most eccentric portion
of the work. If the chalk makes a mark nearly all around the
work, then the centering has been properly done and the center
28

THE SCREW-CUTTING LATHE.
29
may be drilled as shown at D, a hole between 1-16 inch and 1-8
inch in diameter being drilled nearly 1-2 inch deep. A drill larger
than 1-8 inch should not be used for center work except in very
large work. Use small center drills.
After drilling, the work should again be revolved between
centers by hand, for the drill does not always go where it is
wanted and the centers may prove out of true when tested. The
remedy for this is shown by Fig. 7, where the hole has proved to
be out of center. With a very small half-round cold chisel the
metal is chipped away on one side of the hole and a reamer in-
serted, the effect of the reamer being shown at G and H. The
effect of chipping the hole is to draw the reamer toward K. If
the slight chipping shown at E does not draw the hole far enough
k
F
Fig. 7-Truing Centers.
another chip may be taken from the hole shown at G and H,
and the reamer again applied. After reaming it is well to use the
drill again to make sure that the center will never touch the
Fig. 8-Correct Centering.
Fig. 1-Incorrect Centering.
bottom of the hole. Fig. 8 shows the hole drilled deeper than
is necessary, but this does no harm unless there is some other
work in the metal which forbids a hole in that place.
As stated above, correct centering, drilling and reaming is
shown at J, where the lathe center fits perfectly into the hole in
the end of the work-piece. By the way of contrast, a poor job
of centering is shown in Fig. 9, where not only does the lathe
center touch the bottom of the hole, but the reamer was too flat
and the lathe center does not fit the hole made by the reamer.

30
THE SCREW-CUTTING LATHE.
M
a
Good lathe work is an impossibility when the centering is as
shown in Fig. 9.
STRAIGHTENING AND SQUARING-UP.
When a piece of metal is centered as above and placed in the
lathe it sometimes presents the appearance shown by Fig. 10 at L,
M. True, the turning operation could be completed with the
long and short sides on the work as
shown at L, M, but if a great deal
of work has to be done on the metal
while it is between centers, it is ex-
tremely likely that the metal will
Fig. 10—Before Squaring. wear off on short side M more than
it does at long side of the center, thereby throwing the whole
of the work out of alignment. To be sure, the wear would be
slight, but on many lathe operations a shifting of the center even
one one-thousandth of an inch would spoil the job.
In squaring the work a tool is fed in by hand as shown in
Fig. 11, but soon strikes against the center O, and can go no
farther. This leaves a hollow snag
around the center, as shown at P. To
get rid of the snag and leave the end
smooth and square, the tail-spindle
must be unclamped and run slowly
back. At the same time the tool must
be fed in by hand until it has cleaned Fig. 11-Squaring Up.
off all the metal around the center, leaving it clean and smooth, as
in Fig. 12. It may perhaps be necessary to state that the point of
the tool should be just level with the center of the spindle during
the squaring-up business. It will also probably be found necessary
to clamp the lathe carriage so the tool cannot move away from
the end of the work while it is
being squared-up. Clamping
is best effected by throwing in
the lead-screw nut. Then the
screw can be turned by hand
until the tool is brought up to
Fig. 12-A Clean Cut.
the work as far as necessary.
Leaving the nut clamped during the squaring operation will
effectually prevent the tool from moving out of the cut toward the
tail-stock.

THE SCREW-CUTTING LATHE.
31
A word of caution is necessary in regard to clamping the
carriage with the lead-screw. It is this : Never, in any case what-
ever, let the screw feed and the rod feed be in gear at the same
time. If you do, an accident will surely happen, and sooner or
later it will strip the teeth off some of the gears or do some other
damage. Again : Never put rod and screw feeds in gear at the
same time.
STRAIGHTENING LATHE WORK.
No matter how accurately the ends of a piece of work may
be centered, the middle will often run out of true and cause a
great waste of material in getting a fully turned surface the whole
length of the work. Straightening is necessary when the above is
found to be the case, and straightening should be done before
the ends are squared up. If the piece be very crooked, it should
be straightened by the eye as closely as possible, then put between
centers, revolved by hand and the high places marked with
chalk. Place the piece on the anvil, make it lie fair and strike
as hard as may be thought necessary on the chalk mark with a
hammer. Perhaps several blows may be found necessary and in
some cases it is necessary to straddle the spot to be struck over
the low space between face and horn of anvil.
When long pieces of shafting have to be straightened, a screw
press is the proper appliance to use. The press should be mounted
on wheels made to fit the ways of the lathe, then the press can
be moved from one end of the work to the other, as there may
be need of straightening. The smith will hardly have long shaft-
ing enough to turn to warrant the purchase of a screw press,
there-
fore he must get along by peening. To use this method, which
seems rather hard on the lathe, yet which will do no harm if prop-
erly used, the smith-machinist puts the shaft between centers and
chalks the high places as before; then, with preferably a piece
of wood three or four feet long, take a pry over a block placed
on the lathe bed or upon the slide rest. Turn the shaft so that
the lifting end of the lever will come exactly against and under-
neath one of the high-place chalk-marks, then with a rather light
hammer, while a smart pry is taken on the lever, peen the low
or hollow place in the shaft.
The result will be the stretching of the metal fibers at the
point where it was hammered and by properly distributing the
force and number of hammer blows, together with the power

32
THE SCREW-CUTTING LATHE,
placed on the lever, a fine job of straightening may be accom-
plished in nearly as little time as it takes to tell about it.
THE STEADY-REST AND ITS USE.
It will not take the machinist-smith long to find out that it is
a pretty nice piece of work to turn a bit of iron and have it
come round and straight. In fact, he will soon find that this
is an impossible matter, and that he can only turn the metal
"pretty near straight and round.” This is a fact, and, while no
piece of metal can be turned exactly straight and round in any
machine tool yet invented or perfected, still the turning can be
done plenty well enough for all practical purposes provided the
necessary precautions are taken to insure good work.
“Why cannot perfect, straight and round turning be done?”
Because the tool begins to wear the instant it begins to cut, and,
constantly becoming shorter, turns taper instead of straight.
The lathe and the tool as well spring more or less, and when a
hard spot comes to the tool the lathe springs more than when
the metal is soft, therefore there are “bunches” and “ribs” in
the finished work. There are other things which affect accuracy
in lathe work, but it must be considered that the errors are
very small. Any good lathe can be made to work to and within one
one-thousandth of an inch, and the ridges and bunches mentioned
above can be kept down to the one-quarter of a thousandth if nec-
essary, which hardly will be the case in any work likely to come
into the smith-machine shop.
Try to turn a long shaft, and all goes well for about three or
four diameters in length of cut, but after that the shaft springs
away from the tool and good work is impossible. To turn long
pieces in the lathe use must be made of the appliance known as
the “steady-rest.” This useful adjunct of the lathe is made to
stand upon the lathe-bed and is clamped fast thereto by means of
a bolt. The upper portion of the rest is split and hinged that it
may be opened and placed around work already between centers.
Then three pieces of steel are so adjusted that they each touch
the shaft, after which the bolts holding the steel pieces are tight-
ened up and the pieces in question form a bearing for the middle
portion of the shaft, which prevents the springing due to the
great length otherwise unsupported between the lathe centers.
Sometimes it is necessary to set up two steady-rests in order
to do the work which has to be accomplished. Whether one or

THE SCREW-CUTTING LATHE.
33
two steady-rests are used, great care must be taken in setting
them up to see that they are exactly in line with the spindles of
the lathe. It is a pretty nice job to set up a steady-rest in the
middle of a six-foot shaft and have everything in line. To thus
set up the steady-rest, the method described for lining the centers
must be used, a short piece of shaft being put between centers,
the diameter of the short shaft being exactly the same as the long
shaft to be worked, and the length such that, with the steady-
rest in required place, the shaft will barely project through the
steady-rest just far enough to receive the tail-center.
After testing up the tail-center, set up the steady-rest close
to it, and adjust the three bearing strips snugly to the shaft
close to the center, then move the tail-stock back to receive the
long piece of shaft which is to have work done upon it. The
smith-machinist must not get the idea that he can turn a long
piece of shaft accurately by supporting it in one or two steady-
rests between centers. For turning shafting of any length be-
yond three or four feet a different arrangement, a modification
of the steady-rest, must be used. This appliance is known as a
“back-rest,” and is attached directly to and moves along with the
slide-rest. It is usually a plate, carrying a hole, through which
the turned shaft passes snugly. The cutting tools are fastened to
the front side of the rest, and the shaft must pass the tool or tools
(there are usually two, a roughing tool and a finishing tool)
before the same portion can go past the back-rest. The
rest thus forms a sort of bearing, which 'remains constantly at
the point of cut, the result being that the shaft is supported close
to the cutting tool along the entire length of the shaft. The bear-
ing in steady- or back-rest should always be kept well lubricated,
likewise the tail-center of the lathe.
In doing many kinds of work—the cutting-off and threading
of large steam pipe, for instance—it is sometimes necessary to
remove the tail-stock from the lathe and use the steady-rest
instead. The other end of the work being held in a chuck, both
centers being dispensed with, the pipe can be cut off and the
end threaded at will. In thus using the steady-rest, it is necessary
to provide a smooth, true surface for the three steel strips to
bear against. For this reason it is often necessary to carefully
file a portion of the work that the steady-rest may have the neces-
sary bearing. When the work is very rough, or some other

34
THE SCREW-CUTTING LATHE.
a
section than round, it becomes necessary to provide an artificial
surface for the steady-rest to bear against, which may be done
by slipping over the work a sleeve which has been turned smooth
on the outside. The sleeve carries eight set-screws—four at
either end, spaced 90 degrees. Slip the sleeve over the work
true, by means of the set-screws, and adjust the steady-rest to
the sleeve.
THE BACK-GEAR AND ITS USE.
The use of the back-gear is two-fold. It is for the purpose
of supplementing the step-cone when arranging the speed of the
work, and for enabling the small belt to give sufficient power to
take a heavy cut off a large diameter. When turning metal in a
lathe there is a certain speed which gives the best results for steel,
another speed at which brass works the most economically, and
still another speed at which it pays best to work cast iron. The
smith-machinist has all these speeds to learn, and the use of
the step-cone and the back-gear is to obtain an approximation of
these speeds when working one of the metals in question.
This means that the surface of the work in a lathe must
travel at the speeds indicated; therefore the speed of a lathe
must be governed entirely by the diameter and kind of material
which is being operated upon. If a 2-inch piece of soft steel is
being worked-circumference 6.282 inches or 0.523 foot—be
put into the lathe, that piece of metal must revolve at the rate
of about 95 revolutions per minute in order that the surface of the
metal
per minute. Should the work chance to
be inches in diameter, it must needs revolve only one-half as
fast, or about 4572 turns per minute, in order that the speed of 50
lineal feet per minute be maintained. This means that the speed
of the lathe must be reduced one-half. If the necessary reduc-
tion of speed cannot be obtained by means of the step-cone, the
back-gear must be used. In a future chapter the proper speeds
for various kinds of work will be discussed and the various
speeds possible by means of step-cone pulley, both with and
without the back-gear, will be given in full, as adopted by some
well-known lathe builders.
may travel
50 feet
4

CHAPTER V.
THE TOOL POST AND ITS USE.
Next to a good tool, the tool-post of a lathe is about as
important a part as is contained in the whole machine. A tool-
post too light or with an insufficient screw cannot be made to
hold the lathe tool as stiffiy as is necessary and the result will
be a weak, chattering cut, which is a sure preventive of good
work. Not only should the post be strong, but it must also
contain means for quickly and easily adjusting the point of the
tool to any required height. There are several methods of tool
adjustment in use among lathe builders, but the one illustrated
by Fig. 13 is as good, if not better than any of the others.
Referring to Fig. 13, which is partly in section, a piece of
work is shown at A, which is supposed to be in the lathe. The
A
E
А
B
B
mln
J
Fig. 13-Proper Position of Cutting Tool.
A
tool B is in place with its cutting point or edge as close as
possible to the longitudinal or axial center line of the lathe.
new tool has a long vertical point to allow of wear in grinding
the tool, consequently a new tool will stand high above the center
line and will have to be tipped down as shown at A, Fig. 14.
When the tool is about worn out it must be tipped up as at D.
Referring again to Fig. 13, the tool-post I is shown in
place with the screw E bearing upon the tool. Incidentally, a
close watch should be kept over the end of screw E, and if there
35

36
THE SCREW-CUTTING LATHE.
be the slightest sign of any spreading or upsetting the end
should be hardened at once. The test is, to see if the screw will
back out through the nut which is formed in the upper portion
of the tool-post. As long as the screw will come out easily all
is well, but the instant the screw begins to stick attend to it
at once.
COLLAR AND WEDGE ADJUSTMENT.
A
B
cal
Tool
The tool-post C, Fig. 13, is mortised to carry a tool much
19
larger than the one shown in place.
When work has to be done at a distance
from the tool-post, as in deep channels,
between collars, etc., there is need of a
long tool overhang, therefore the tool-
post must have a hole large enough to
receive the large tool section necessary
for supporting the necessary overhang.
The upper portion of the slide rest is
LUME
sometimes called the "anvil” and is shown
at J. An undercut groove is made in
Fig. 14-Adjustment of
by Means of Collar
this part of the slide rest, to receive the
and Wedge.
lower end of the tool-post as shown. Be-
tween the "anvil” and the tool is a wedge F and a collar G, of
peculiar construction, as will be later described and shown by
Fig. 15, the upper portion of the collar being
turned concave to fit the bottom of wedge F, Fig.
13, and more clearly shown by Fig. 16. The bot-
tom side of the wedge is finished to fit the concave
surface of collar and the upper surface of wedge is
tooled or cut like a file to prevent slipping of the
lathe tool, which may be screwed down against it. Fig. 15-Tool
The wedge F, Fig. 13, is just wide enough to go
Sectional
freely through the mortise in the tool-post. The evation).
collar G is usually made about two and one-half times the diameter
of tool-post and of varying thicknesses, according to the size of
the lathe. By moving endwise the wedge F the point of the tool
is raised or lowered so as to coincide with the center line of the
lathe. The action of the wedge is more clearly shown by Fig. 14,
where the newly forged tool is shown with its long neck at A, the
wedge B having been pulled back on collar C, to bring the point
OH
Post Collar
(Plan
a n d
El-


THE SCREW-CUTTING LATHE.
37
of tool to center line of lathe. As the tool is ground off during
use the shape approaches that shown at D, the wedge E having
been pushed forward on collar F, so as to maintain the cutting
edge of the tool on the center line of the lathe as before.
"CLEARANCE" AND "RAKE."
Fig. 13 shows the tool set with point on center line and a
certain angular distance between the end of the tool and the
vertical tangent of the surface being cut. This distance is
marked I, and varies in different kinds of work and will be
discussed later. For present purposes it will
answer to give just enough clearance so the
tool does not rub against the piece of metal to
be turned, say about 3 degrees for steel,
wrought iron and brass, and 4 degrees for
Fig. 16-Tool Post
cast iron. The "clearance” is sometimes called Adjusting Wedge.
“bottom rake,” but the first name is the better one.
The "rake” of the tool is the distance k, from the line of
the tool to the cross-center line of the work in the lathe. It is
better to call the distance k the "top rake,” which is about 22
degrees. This angle, added to the clearance of 3 degrees, makes
a total clearance of 25 degrees, which subtracted from 90 degrees
leaves 65 degrees, the “cutting angle” of the tool shown in place
by Fig. 13.
For steel and wrought iron the top rake may
be as above, but for cast iron the top rake had better
be diminished to about 15 degrees, thereby giving a cutting
angle of 72 degrees. For brass the angle should be still slightly
increased to about 80 degrees, which with a clearance of 4
degrees leaves 76 degrees rake or top clearance.
A tool, in order to feed properly along the work, must have
another form of clearance as shown at m, Fig. 13. This form of
clearance is called the "side clearance," which should be very
small, probably not more than the bottom clearance of 4 or 5
degrees. In some types of tools, as shown by Fig. 13, side
clearance may be given a tool by swinging the tool sidewise
the distance n, which turns a part of the end clearance into side
clearance. The tools which can be used in this way are not many,
They are the “front tools” like round-end brass or cast-iron turn-
ing tools and cutting-off tools, which make good ones for finish-
ing, if
ground off a little on one corner. Such tools can be given
a


38
THE SCREW-CUTTING LATHE.
a little side clearance by turning them slightly as shown at n,
Fig. 13.
FORMS OF SIMPLE LATHE TOOLS.
Several ordinary forms of lathe tools are shown by Fig. 17.
These tools may be purchased in “sets” as above, all sharpened,
ready for use, at a cost of $2 to $3, but in a size too small for
use in the smith shop. The steel from which these small tools
are made is about 1/4 x 1/2 inch and they are from 27/2 to 3 inches
long. Of course these tools may be purchased in the size needed,
but they will cost a good sum of money and there are several
P
o
F
6
13
NA
15
Fig. 17-Common Forms of Lathe Tools.
tools among them which will not be needed for a long time in
the kind of work the smith is likely to do.
The argument for buying the small tools is to keep them
for patterns and forge tools from 12 x 1 inch steel, making them
just like the small ones, except for size. Furthermore, the small
set of tools may be kept at hand to serve as models for grinding
the larger tools, at least until the smith has "learned the trade"
far enough to know why he gives a certain shape to a certain
tool in order to obtain certain effects in the lathe. The 1/2 x 1-
inch tools may be purchased for about $5.

THE SCREW-CUTTING LATHE.
39
Directly in line with this matter is the arrangement of the
tool as shown by Fig. 14. Here the tool is tipped more or less
by means of the sliding wedge in order to keep the point of the
tool on the center line of the lathe. It will be noted that as the
point of the tool is tipped downward, the clearance becomes
greater and the top rake less. To a considerable extent this
matter regulates itself, for as the tool is ground away on top
it is natural for the “machinist-smith” to also grind off the face
of the tool as shown by the dotted line g, to which point the
grinding will probably have progressed by the time the tool is
ground down short as at D.
Grinding off the front of the tool increases the clearance
when the tool is low, and grinding off the top of the tool
decreases the clearance in about the same ratio, therefore the
clearance remains practically the same, the smith noting when the
tool does not have quite clearance enough, and correcting that
matter the next time he grinds the tool.
Referring to Fig. 17, the names and uses of the several tools
are as follows: Nos. 1, 2, 3 and 4 are what is known as "side
tools.” They can be used for almost any kind of exterior turning,
but they may be classed as "old style” tools, as they were used a
great deal more fifty years ago than at present; still, for many
kinds of work these tools are not equaled by any other form of
tool inade.
Nos. 5, 6 and 7 are "diamond points,” and are used for
general work, heavy and light. Nos. 8 and 9, "half diamond” and
"round nose,” for turning cast iron and brass. No. 10 is a "water
finishing” tool. No. II is for "cutting off” and is made in differ-
ent widths, as will be described later. Nos. 12, 13 and 14 are
"thread” tools; No. 13 is for roughing or taking the first cuts,
No. 12 for finishing the threads and No. 14 is a bent thread
tool for getting into corners. No. 15 is an "inside” thread tool
for cutting threads inside of nuts and other work, and No. 16
is a boring tool for working inside surfaces.
PROPER SETTING OF LATHE TOOLS.
Although a tool may be made to work in almost any way.
however it
may be put into the tool-post, there is a certain way
whereby the tool does better work than if set some other way.

40
THE SCREW-CUTTING LATHE.
Fig. 18 shows a tool improperly set to do good work, especially
in the heaviest cuts that can be taken by the lathe. As shown
by the engraving, the tool is feeding in the
direction of the arrow, but bears against two
edges of the tool-post at A and D. The tend-
ency of the cut, especially if very heavy, is to
push the tool around in a direction from A to
B, and the other end of the tool goes from D
to C.
In setting a tool always remember this
tendency of a tool to swivel under the tool-
post screw, and to prevent that action set the
Fig. 18—Tool Improp-
erly Set in Tool Post.
tool to bear against B and C and there can be
no swinging of the tool either into or out of the cut.
Fig. 13 gives a clue to the proper setting of almost any
lathe tool as far as height is concerned for all tools must
be set in that manner, but otherwise the tools must be differently
set according as they are to take heavy metal removing or light
finishing cuts. Nos. 1, 2, 3 and 4 should all be set for straight
turning as shown by Fig. 19, the heel or shank of the tool going
Fig. 19-Uses of Side Tools.
first, so that the tool makes a "pulling" cut instead of a pushing
one, as is the case with the diamond points 5, 6 and 7, Fig. 17,
which are all end-cutting or “push” tools.
The method of setting the tool in the post as shown by Fig.
18 applies to the side tools fully as much as to the diamond
points. For heavy cuts that setting of the tool is very necessary,

THE SCREW-CUTTING LATHE.
41
but for finishing and other light cuts it may be neglected, still
it is an excellent way of setting a tool of any kind, for any cut.
The proper method of setting the diamond point tools was fully
illustrated by Fig. 13, and the roughing and round nose tools
8 and 9, Fig. 17, should be set in the same manner as more fully
shown by Fig. 20.
А
B
E
9
11
13
12
Fig. 20-Uses of Round Nose, Cutting-off and Thread Tools.
The method of setting the boring tool and the internal
threading tool is shown by Fig. 21 at B and A, respectively. A
more comprehensive view of these tools may be had at D and E,
Fig. 22, where the proper setting is shown in plan and in the
end view. It will be seen from this engraving that the tool is
always set on the center and that it is ground to give about the
same clearance and rake no matter what kind of a tool is being
used or where it is to be set. Let the "smith-machinist” once
get this matter well fixed in his mind and he will have no trouble
in grinding or setting any tool to take a clean, smooth cut.
The method of setting the water-finish tool is also shown by
Fig. 20, as also is the setting of the cutting-off and thread tools.
8
!!!!
Fig. 21-Boring and Inside Thread Tools.
The water finish tool 10 is set square against the work, but the
corner which is to be fed in advance is ground back a little. This
will be more fully shown in Fig. 22. The cutting-off tool is set
in exactly the same manner as the water-finish tool. In fact,
there is little difference between the two tools, and one may be

42
THE SCREW-CUTTING LATHE.
used in place of the other to advantage. In the engraving the
cutting-off tool is shown very narrow, but its width is merely in
accordance with the depth of cut to be made. Cuts only a half an
inch or so deep may well be taken with a tool only 1-16 inch
wide, while cuts 2 inches deep should have at least 3-16 inch
width of tool to enable them to stand up to the work.
As regards the width of a tool necessary for a water-finish
cut, there is nothing arbitrary about the matter. It is only neces-
sary that the tool is more than twice as wide as the width of
cut taken by the lathe-width of cut, not depth. Fig. 22 illus-
trates this matter, also the grinding back of the advance cutting
corner of the tool as noted in the preceding paragraph. No
matter what the angle at which the face has been ground, place
ili
Fig. 22-Setting Lathe Tools for Finishing Cuts.
that face square against the work and let the shank of the tool
point in whatever direction it may.
The same is true of the water-finishing tool. Fig. 22 at B
shows how the advance corner is ground away and the remainder
of the tool set square against the work. Water should be supplied
all the time when taking a finish cut, either by hand, from a squirt
can, or from a can with a small hole therein, suspended above the
work and arranged to feed along with the slide rest. Soda
water, soap suds, or any similar substance may be used, but plain
water is all that is needed. The water-finish tool, 1/2 inch wide, is
wide enough to stand 38-inch finishing cuts. The smith lathe
will never be called upon to make finishing cuts more than 1-32
inch wide, therefore the narrowest cutting-off tool is wide
enough for a water cut.
Bear in mind that the whole principle of finishing cuts, as

THE SCREW-CUTTING LATHE.
43
noted above, depends upon a "double-line” cut. This is shown
plainly by Fig. 22, where one portion of each tool is ground to
bear against the finished work, while the other portion of the tool
is cutting down the metal ahead of the tool. Arrange every
finishing tool in this manner, and a good clean cut will be the
result, no matter what kind of a tool is being used. The rule
applies to every form of tool, inside or outside.
The thread tools must in every case be set square against
the work and inclined neither back nor ahead. The thread tools
are sometimes bent to enable them to be set easier in the tool-
post, as in tool 14, Fig. 17, and this is also true with the other bent
tools; side tools 3 and 4 and cutting-off tools and diamond points
are frequently bent to permit their use in some corner of work
which cannot be gotten at with the ordinary form of tool.
The roughing and finishing thread tools are applied as shown
at D and E, Fig. 20. A roughing tool is used for the simple
reason that it is impossible to keep the point on a sharp thread tool
when roughing out the first portion of the thread. Frequently
the machinist uses a single tool and grinds off the point when
he does the roughing, but this makes another grinding necessary
when the finishing cut is to be made, and is an expensive way,
hence the use of the roughing tool 12, Fig. 17, and D, Fig. 20,
which also shows the setting of the thread finishing tool at E.

CHAPTER VI.
DEPTH OF CUT.
When taking a plain cut, one of two things must be the
object: either to remove a lot of metal, or to obtain a finished
surface on the metal which is being operated upon. It is not
.
good policy to use a larger piece of metal than is necessary, for
removing metal in the lathe is a costly operation. It is much
better and less costly to do the metal removing in the forge
and leave just enough metal to finish to size—and this is where
the good smith comes in, for the writer has seen some of the
latter craft who could forge fully as close as some machinists
could work with a lathe!
When metal must be removed—and frequently it has to be
done, no matter how close the forging—set the tool to take as
thick a cut as the lathe (or the work) will carry. It takes much
less than double the power to run a cut 18 inch deep than it does
to run a cut 1-16 inch deep, for the lathe friction is the same in
both cases. Use a stiff tool and grind it in such a manner that
it turns out a smooth continuous chip when cutting wrought
iron or steel. The continuous chip business cannot be done when
cast iron or brass is being worked, but the chip is always the test
for the condition of a tool when cutting wrought iron or steel.
Never try to work with a dull lathe tool (or any other tool).
It requires too much power when removing metal and a dull tool
never gives a good surface when finish is required. Never let a
tool go until it needs a lot of grinding, and never grind a tool
temporarily--that is, never sharpen just the point, so that the
job can be finished in a hurry. Such a course never pays. The
.
time saved in temporary grinding is more than lost by trying to
make a poorly fitted tool do the work. Grind from the bottom
of a tool, every time, and grind as well as you know how. It
pays.
THE PROPER SPEED.
"How fast should a lathe be run on various kinds of work ?"
a
is a question which has many times been “fired” at the writer,
44
THE SCREW-CUTTING LATHE.
45
"WVIOLETI
10"
”,98
2/ BELT
and the same answer must be given every time, to wit: Run the
lathe as fast as the tool will stand it. Old-time machinists used
to run lathes much slower than the present practice calls for,
and speeds of 20 feet per minute were often found. In many
shops, the speed for turning gray cast iron lies between 32 and
100 feet per minute for first or scale cuts; 40 and 130 feet for
second cuts, and 70 to 250 feet
per minute for finishing cuts.
But these speeds are much
greater than the smith will ever
use for work that will come to
him, therefore the several lathe
speeds will be calculated for or
at 20 feet per minute.
The writer is not aware of
the kind of lathe possessed by
any particular reader, therefore
he is unable to use the exact
diameters of the step pulleys or
to figure exactly the speed at
which the lathe will run with the
belt upon any particular step
with back gear in or out, but, for
example, will take the data of a
certain lathe which has step pul-
leys as follows: 434 inches, 61/2
inches, 81% inches, 10 inches and
1134 inches in diameter. The
pulley on the counter shaft has
steps of exactly the same diam-
eters, and, as shown in Fig. 23,
the
Fig. 23—Lathe Step Cones and Back Gear.
gear on spindle has 30 teeth,
meshing into a gear of 90 teeth on the back gear, which also
carries another gear with 18 teeth, which engages a gear with 72
teeth on the lathe step pulley.
Thus the ratio between the pulley and the spindle when the
back gear is in use is 12 to 1, and the spindle speeds are as fol-
lows: With belt, 371, 231, 150, 97-5, 60.6 revolutions per minute,
the counter shaft running at 150 revolutions per minute. With
back gear in use the speeds are: 30.9, 19.25, 12.5, 8.1 and 5.05

90 TEETH
18 T
30 TEETH
47' DIAM.
10" ,
12 TEETH

46
THE SCREW-CUTTING LATHE.
revolutions per minute. The ratios between cone step speeds are
as follows: 1.60, 1.54, 1.53 and 1.60, and the ratio between the
belt and gear speeds is 1.96.
With the data given above we can figure the speed at which
the spindle should be made to run to give as near 20 feet per
minute as possible to the work in the lathe. The method is some-
thing as follows: The work is 10 inches in diameter. What step
should the belt be placed on to drive the work 20 feet per minute,
or as near that speed as possible? 10 X 3.141 • 12 = 2.62
(slide rule calculation), which means that the work has a cir-
cumference of that number of feet. Divide 20 by 2.62 and the
quotient is 7.64, the number of revolutions per minute the spindle
should run to give the surface of a 10-inch cylinder a velocity of
20 lineal feet per minute. From the data given above it is found
1/2
Fig. 24-Diameters of Work Giving 20 Feet per Minute Velocity.
that the nearest speed is 8.1 revolutions per minute, which is
given when the back gear is in mesh and the belt is on the step
next to the largest. The revolutions are 8.1, hence the surface
travel will be 8.1 X. 2.65 = 21.45 feet per minute, nearly.
Fig. 24 gives a graphic representation of the different diam-
eters of work which will give exactly 20 feet per minute cutting
=

THE SCREW-CUTTING LATHE.
47
speed. The smaller sizes are not given, as the circles would be
too small to distinguish. The smith-machinist will do well to
make up a similar set of circles, either full or half size, and keep
them near the lathe until he becomes accustomed to obtaining
the proper speed of revolution for any work he puts in the lathe.
After a time the circles will not be needed, for the right velocity
will come instinctively and without any apparent effort on the
part of the operator to study it out. For the present, however,
make a set of "Velocity Diameters,” and draw circles to them.
They will come very handy.
The tendency of machine shop practice is to as great speeds
as the lathe tools will stand up under, and the 20 feet per minute
rate of feed is hardly ever found in practice nowadays. Still, for
the beginner at lathe work, it is an excellent speed to follow. In
a paper recently read before the Cincinnati Metal Trades Asso-
ciation, the result of over 400 records of routine turning was
tabulated, and it was shown that for turning gray (cast) iron,
the speed in feet per minute varied from 32 to 115 feet for rough-
ing cuts, or 35 to 135 feet for second cuts, and from 70 to 240
feet for finishing cuts. For machinery steel the speeds given are
considerably higher, ranging from 40 to 163 feet for roughing,
45 to 150 feet for second cuts, and from 68 to 390 feet
per
minute
for finishing cuts. It is stated that the tools stood up to this
usage for different periods of time, ranging from 27/2 minutes
to half an hour. It is not expected or recommended that the
smith-machinist will attempt the higher speeds. When the smith
gets so that he can make a tool stand up under them he may be
assured that he knows how to forge a good lathe tool, also how to
grind and set that tool exactly right.
Probably the early attempts to
work a lathe tool at high speed will
prove very disappointing, and the tool,
after a few minutes' use, will appear
something as shown by Fig. 25.
Always be on the lookout for a thing
like this and never let a tool get
Fig. 25-Point of Tool Worn Off.
into such a condition. If such use is permitted, the tools will
soon be very scarce in the shop. Realize what it means to have
a tool worn off, as shown at A, Fig. 25. It means that fully one-
third of the effective cutting metal in the tool must be ground off
A
8
E

48
THE SCREW-CUTTING LATHE.
a
and wasted before the tool is fit for service again. To grind
this tool, two courses are open: Either the top of the tool must be
ground off down to the line B, or two sides of the tool must be
taken down to the lines C, D and E. The first method is the
best, for less metal will be wasted on the grindstone or emery-
wheel, but the tool will need reforging quicker than if it is ground
off on the vertical faces, C and D.
The lesson to be learned from an occurrence of this kind is :
Never let a tool get as dull as shown by Fig. 25. The time to
grind a tool is as soon as any appreciable wear appears at A. A
tool cannot get into this condition without first becoming slightly
rounded on the cutting edge, a condition which immediately be-
comes manifest by the chip becoming rough and lumpy, more
heat being manifest between tool and work, and by symptoms of
distress manifest generally by the lathe and by the belt in
particular.
Too fast a speed is frequently made manifest by a tool taking
the shape shown in Fig. 25. Indeed, distress is always mani-
,
fested by the tool when the cutting speed is too high, although
similar results are sometimes obtained at the tool point by
improper tempering and by poor shaping or grinding. Some-
times the novice grinds the tool so fast on an emery wheel that the
temper is run out of the point of the tool, which immediately
wears off to look like Fig. 25. The operator will soon learn to
distinguish between trouble caused by too much speed and that
due to too soft a tool.
a
ROUGHING AND FINISHING CUTS.
In setting a tool for a roughing cut, the point of the tool
should always be protected by being made to run in clean metal
underneath the outer scale or skin of the work. In roughing cast
iron there usually is more or less sand adhering to the metal,
and if the point of the tool is made to scrape through or against
such scale, the grindstone will be in more use than the lathe.
For roughing cuts, the tool should take a cut thick enough to
make sure that the tool works below the scale. Then, only a
thin edge will come in contact with the scale, and where that
edge does come against it, the scale has been broken or torn
away by the wedge-like action of the point of the tool which is
slightly in advance of the portion of the tool which cuts the skin.

THE SCREW-CUTTING LATHE.
49
Fig. 26 shows the proper setting for a roughing cut in cast
iron, the round nose tool being used. The advanced point of
the tool B cuts in clean metal and does not come in contact with
scale, which only can come in contact with the tool at C, and
B
Fig. 26-Taking a Roughing Cut.
even then, as stated in the previous paragraph, the advance por-
tion of the tool at B serves as a wedge to open up the chip,
breaking it away from the uncut metal, so that in reality there
is very little cutting actually done by the tool at C.
Second and finishing cuts have no scale to contend with,
therefore the tool can be set to cut on the surface as much as
is necessary. In fact, no attention is paid to the surface of
the work when setting a tool for a second or for a finishing cut.
The tool is placed to bear fair against the finished surface only,
leaving the matter of the rest of the cut to take care of itself.
WATER CUTS.
As stated elsewhere, a particularly fine finish can be obtained
on a turned surface by keeping the tool and the work wet with
water or some other substance. The reason why the tool cuts
cleaner when wet is that the water or other substance serves
as a sort of lubricant to the tool and enables the tool to cut with
less expenditure of energy than when it is not lubricated. An
instance is the use of oil when chipping wrought iron with an
ordinary cold chisel. The oil lubricates the cut so the chisel
per-
form its work easier, therefore cleaner, than when used dry.
Another reason for using water on a finishing cut is that the

50
THE SCREW-CUTTING LATHE.
heat generated at the cutting line is carried away by the water,
enabling the tool to keep cooler and therefore retain its edge
a much longer time. Not only does the water carry away a
portion of the heat generated by direct increase in temperature of
the water flowing over the cut, but much more heat is absorbed
by a portion of the water being turned into steam at the point of
cut. This is the real source of cooling and it probably has a
good deal also to do with the quality of the finished surface.
USE OF SODA WATER AND OF OIL.
In some shops, pure water is used for finish cuts; in other
shops, a sort of soda water is used. Again, other shops make use
of soap suds, while other shops use oil. Any of these substances
will enable a lathe tool to take a much smoother cut than it is
capable of when dry. Oil is not a good substance to use on
finishing cuts, or on any other lathe-work except polishing.
Water is the best. Soda dissolved in the water does three things
which are beneficial. Soda water is a better lubricant than pure
water and has more the nature of oil, thereby reducing slightly
the friction of the tool against the work. Soda water has a higher
boiling point than pure water, thereby enabling the water to
become heated hotter before it is flashed into steam by the heat
generated in cutting iron. Third, soda water will not rust the
work as pure water will, the alkaline solution holding the oxygen
of both water and air well in check, therefore soda water fills
the bill as a water-cut material. Many other substances will
help make as smooth a cut as soda—salt, for instance, will do as
well as far as cutting is concerned, but the manner in which a salt
solution will let oxygen act upon the surface of iron or steel
forever prevents the use of salt water for making finishing cuts.
In this connection, it may be well to call attention to the fact
that there are liquids which, instead of acting as lubricants when
applied to cutting tools, seem to aid the tools in taking hold of
the work. Spirits of turpentine, applied to a cutting tool, helps
to cut material which, without the liquid, the tool could not
touch. Substances like glass may be turned or drilled if the
tools be kept wet with turpentine, benzine or similar substances.
But they do not make the tool cut smooth, hence they are worth-
less for use on finishing cuts.

CHAPTER VII.
FILING WORK IN THE LATHE.
The proper method of setting tools for finishing cuts was
described in Chapter VI. and only practice in accordance with
the directions there given is necessary to enable any good work-
man to turn out work with a smooth finish which is accurate
to size as well as of good appearance. When it is not convenient
to take a water cut over the work, a finished surface may be
obtained by first filing the work in the lathe, after which the sur-
face is ground with emery and then polished by any adequate
substance like chalk or clay.
When it is decided to file up a piece of work in the lathe
with a view of ultimately giving it a high polish, a good deal of
attention must be given to the selection and use of the file. A
coarse file should never be touched to work between lathe centers
for the purpose of preliminary polishing work. If there is
material enough to be removed to warrant the use of a coarse
file, then take another light cut with the lathe tool and remove the
superfluous metal.
All the filing that should ever be done is sufficient to remove
the tool-marks, and the skillful workman will see that these marks
are very slight. Nothing coarser than a mill file should ever be
touched to the work and then that file should be used lightly and
sparingly. Remember, that as soon as filing commenced, the
work begins to depart from a true cylindrical form and becomes
more or less irregular in section—the more it is filed, the more
irregular will it become.
The first stroke of the file means that flat places are being
made, therefore it is advisable to speed up the work so that a
single stroke of the file will reach at least entirely around the
object being filed. For very small work, the highest speed may
be used for filing and larger diameters should have the speed
reduced in proportion. A ten-inch shape should revolve at least
60 revolutions per minute for filing purposes. The file should be
applied lightly, and with a steady pressure, and moved slowly
51

52
THE SCREW-CUTTING LATHE.
against the work. Never give the file a quick jerky motion while
filing in the lathe—or anywhere else, for that matter.
HOW TO HOLD A FILE.
See that there is a firmly fitting handle on the file. Never
use a file without a handle—and grasp the handle with all the
fingers of one hand, then take the tip end of the file between
the thumb and forefinger of the other hand. Bear lightly against
the work and push the file lightly and evenly along so that its
whole length, from point to handle, comes in contact with the
work. In selecting a file, sight along the sides and see that there
are no short crooks in the file. A file which is full of hollow
places and bunches is not fit for lathe filing. If you have been
caught into buying such a file, use it for something other than
finish filing in the lathe.
If the file is new, dip it in gasoline or naphtha to remove
every trace of grease. Brush the file with the file-card to make
sure that no grease remains in the bottom of the cuts. As soon
as the gasoline evaporates, rub some chalk over the file. The
chalk will fill the spaces between the teeth and prevent the file
from filling up or clogging with metal filings. While the file is
clean, it can be pushed with a smooth easy motion along the
revolving work, but as soon as one or more particles of metal
stick between the file teeth, a roughness will be felt in the advance
of the file as it rides over the obstructions between the teeth.
The result will be bad scratches in the work where the caught
filings tore their way along the surface of the work. Just as
soon as the least roughness is felt in the advance of the file, clean
it with the card and rub in some more chalk before taking
another stroke.
It is impossible to do good work with a dirty file, and never
a stroke should be taken when the feel of the file shows that some
of the teeth have become clogged up. File "cards” are on sale
in the hardware stores. They consist of a piece of wood con-
veniently shaped for the hand, with a bit of “card clothing” tacked
upon the board. The “clothing” is a piece of leather filled with
fine wire steel teeth which project about 38" from the leather.
Rub this appliance hookwise in the direction of the angle on which
the file was cut and it will clean out all the foreign material which
may be lodged there, with the exception of some bits of metal
a

THE SCREW-CUTTING LATHE.
53
which have become hammered between the teeth too strongly to
be removed by the brush-cleaner. These bits of metal are what
cause trouble when filing. To remove them, take a sharp pointed
awl (a horseshoe nail will do, if nothing better is at hand) and
NUTI
Fig. 27—“Picking" a File.
push it sharply along the channels between the file teeth. A
vigorous application as described will remove the most obstinate
bits of metal. The application of chalk prevents, to a certain
extent, bits of metal from becoming wedged between the teeth of
the file. Fig. 27 shows how the bits of metal are taken out.
EMERY CLOTH AND ITS USE.
After the tool marks have been removed with a file tech-
nically known as a “mill” file, use a finer file of the cut known as
'smooth.” There is a still finer cut of file, but it does not pay to
bother with it in finishing lathe work. Emery paper will do the
business quicker than a file and at the same time will keep the
surface more nearly cylindrical than is possible by filing.

54
THE SCREW-CUTTING LATHE.
Wrap the emery paper or cloth around the work in the
direction the lathe is running, then press upon the paper with one
or both hands and the paper will get in its work. Use paper a
little finer than the file, and as soon as the file marks disappear
use still finer paper, changing to still finer emery as the coarse
marks disappear. In a few minutes a dull gloss will appear on
the surface of the metal and the finish may be increased by the
continued use of the last piece of emery cloth until it becomes
filled with metal from the work being polished. Then the emery
can cut less and the metal chips act as a sort of burnisher to polish
the work.
If a very high polish is required, the emery paper may be
replaced with rotten stone and later by crocus powder, which will
give the work a surface as smooth as can be obtained. Bear in
mind that it is of no use to try to polish a rough surface. Such
an attempt will only polish the high spots, while the low places
remain as rough holes among the highly polished high spots.
A true surface must first be obtained before polishing can be
effected. This is gained by the filing and emery papering
described. As the carriage painters put it, the surface must be
made “level” before it can be finished with even a decent polish.
GRINDING WITH EMERY WHEELS.
Some people entertain the idea that a polish can be given
to metal by means of emery wheel grinding, but nothing can be
further from the truth. The object of emery wheel grinding is to
obtain a true surface, either flat or cylindrical, not to put a polish
on the surface. True, a surface can be obtained by successive
treatment with finer and finer graded wheels, and a finishing
touch with rouge on a rag wheel, which will impart a splendid
surface to the work, but that does not constitute emery grinding
with wheels.
Probably all the wheel emery grinding which the smith
machinist will have anything to do with, is the placing of an
emery wheel upon a fixture which is held in the tool post of the
lathe and driven from a drum overhead, the work being revolved
at a slow speed while the emery wheel is traversed back and
forth along it.
The principle of a tool post rig is shown by Fig. 28, and the
smith can easily rig up the necessary apparatus for himself, or he

THE SCREW-CUTTING LATHE.
55
can purchase the entire outfit ready made. Briefly stated, the
device consists of the emery wheel A, attached to the arbor of
the tool-post bearing B, which is so shaped that it is put into
the tool post exactly as if it were an ordinary tool. The bearings
E
B
Fig. 28-Tool Post, Overhead Grinding Rig.
are fitted with oil cups and an adjustment for wear. The drum
C is mounted overhead, independent of the lathe counter, and is
driven by its own belt D; tight and loose pulleys being supplied
for starting and stopping the drum.
The object to be ground, E, is put between centers exactly
as for turning, and especial care is taken that the centers are in
good condition and well fitted to the work. In grinding, it is
necessary that the wheel always traverses entirely past the end of
the work. If the wheel is reversed before its width passes
entirely off the end of the work, true grinding is impossible.
KEEPING EMERY WHEELS IN ORDER.
In order to do good grinding it is absolutely necessary that
the emery wheel be round and free from all low places, hard
lumps, or glazed spots. If the wheel runs the least bit out of
,
true it must be rounded up before a decent job of grinding can
be done. To dress an emery wheel a diamond tool is an absolute
necessity. No other appliance will take the place of the diamond

56
THE SCREW-CUTTING LATHE.
for this service, and a diamond tool costing two or three dollars
will, by careful use, last for years.
With a diamond tool, the emery wheel can be turned as if
it were a section of a turnip or some other soft material, so easily
does the harder diamond take hold of the hard emery. Keep the
diamond handy to the emery wheel, no matter whether you
are going to grind a piece of steel for a fit within a quarter of a
thousandth of an inch, or whether you are going to sharpen the
chilled point of a plow. It is just as necessary that the wheel run
true in one instance as in the other, and the quality and quantity
of the work turned out in either instance is in direct ratio with
the condition of the emery wheel, other things being equal.
To true up an emery wheel, put a solid bearing within a
quarter of an inch of the wheel and rest the diamond tool firmly
on that rest or bearing and turn up the wheel as if it were a piece
of wood in a speed lathe. During the turning process the emery
wheel inay run at its full regular speed and need not be slowed
down for truing up.
In selecting a diamond tool, pick out one from which the
handle may easily be removed, then when an extra nice wheel is
required the tool minus its handle may be put into the tool post
of the lathe and the wheel dressing done in short order.
grinding for accuracy of diameter and surface, and that is what
is desired in this kind of emery work, bear in mind that an
object like a roll or a wheel which is to be made to run accurately
in bearings cannot be accurately ground on centers.
For instance: if it was desired to make the emery grinder as
true as possible it would not do to put the wheel on its arbor
between the lathe centers and grind the wheel thus. It would
be extremely probable that the wheel would not run true when
it was put back in its own bearings. To obtain extreme accuracy
in a case of this kind, grind up the bearings of the emery wheel
shaft, then fit them closely to their bearings, after which put the
wheel in the tool post, fasten the diamond tool to the slide rest
as if it were to be ground, and then feed the wheel past the tool.
This will do the trick, and the wheel will come out as accurate
as it is possible to make it.
If the smith ever has occasion to grind up hardened rolls
for a jeweler or some other chap to roll small strips of metal
with, never try to grind the rolls on centers. Grind up the roll
In emery
a

THE SCREW-CUTTING LATHE.
57
bearings on centers, then put the bearings in their own boxes and
grind the roll in its own supports.
PUFFING AND POLISHING.
For finishing or polishing irregular surfaces, the smith may
with little expense rig up some buffing wheels, which, supple-
mented with “rag” wheels, will enable him to do almost any job
of polishing which is likely to be brought to him. Buffing wheels
may be made of well-seasoned white pine or mahogany, thin
wood being used and the grain crossed, the layers glued together
under pressure, the wheels mounted on mandrels and turned
smooth and true. It is best to fit each wheel to its own mandrel,
and let it stay thereon all the time.
The best wheels should be faced with leather glued on, the
leather turned to a fine surface, then tallow is rubbed into the
leather and the wheel rolled on a board sprinkled with the fine
polishing material. This type of wheel is ready for use at once
after applying the emery.
DANGER OF LATHE GRINDING.
Having very briefly described the methods of lathe grinding
and polishing, a word of caution is necessary.
There is no
work which will so quickly wear out a lathe as tool-post grinding.
The reason is that the emery particles torn from the wheel dur-
ing the grinding operation find their way into the bearings of the
lathe, and upon the sliding surfaces, where they imbed them-
selves and cut the surface. Tool-post grinding, then, should be
sparingly done, and as soon as possible rig up separate machines
for this work, particularly for polishing and buffing.

CHAPTER VIII.
a
SCREW CUTTING.
Screw cutting is one of the most interesting operations per-
formed with the lathe. It is second in point of interest only to
geometrical turning and is of much more use in practical me-
chanics. The patterns traced in fine lines on the backs of bank
notes and watch cases are formed by a cutting tool held in what
is known as the “Geometrical Lathe,” or in a "geometrical chuck,"
which may be used in an ordinary lathe. The screw is formed
by moving a cutting tool endwise on a rod a certain distance
during the making of a certain number of revolutions of the rod.
Technically a screw is nothing more or less than “a wedge
wrapped around a cylinder,” as may be easily proven by cutting
a triangular bit of paper and rolling same around a pencil, keep-
ing one edge square with the pencil while the other edge of the
paper winds on it exact imitation of a screw. In fact, it is a
No man or machine has yet succeeded in making a
perfect screw. All the micrometers and instruments of precision
are made imperfect by the impossibility of making a screw abso-
lutely perfect. Screws are made almost perfect, but never quite.
The error in a good screw is very slight and the smith will never
be troubled by it in any work he will do. In many cases of pre-
cision measurements a screw is wanted which shall be of an exact
number of threads per inch and which shall be even from one
end to the other. It is not yet possible to fill either of these con-
ditions. A screw has never been made with an exact number of
threads to the inch, and a long screw made with the utmost care
and highest skill known will prove irregular. Some portions will
be found “fast” while other portions are “slow.” That is: The
nut will get ahead or lag behind what should be its proper move-
ment, making a table of corrections necessary for every inch of
the screw used in high grade work.
screw.
SPINDLE, STUD AND LEAD SCREW.
In front of the lathe, as described in Chapter I, will be found
a rod with a key-way cut along that portion of its length over
58

THE SCREW-CUTTING LATHE.
59
a
which the slide rest passes. With the use of this rod screw
cutting has nothing to do. Near the rod is a long screw which
also passes through that portion of the slide rest which hangs
down in front of the lathe and is known as the “apron.” The
gearing contained in this apron should never be neglected. The
smith should investigate it and know how it is arranged, then
he should oil it regularly, keep all parts clean and see that no
screws get loose to let lost motion get between any of the parts.
To do good lathe work the machine must be kept clean, oiled and
tight. If you can't do that sell the lathe and buy a shovel instead.
The screw is connected and disconnected to the apron by
means of a split nut, which in turn is operated by a lever pro-
jecting through the apron. To cut a screw the rod feed is dis-
connected and the nut clamped upon the lead screw, as it is usually
called. The lead screw must be connected with the spindle by
means of gears, and upon the number of teeth in the gears
depends the pitch of the thread which will be cut by the lathe
as set up. For instance, if gears of equal teeth be placed on both
spindle and screw then the screw cut in the lathe will have the
same number of threads per inch as the lead screw. If a gear
having twice the number of teeth be placed on the spindle, the
same gear remaining on the screw, then the lathe will cut a
screw with only half as many threads to the inch as the lead
screw. If the position of the gears be reversed and the larger
gear placed on the screw, then the lathe will cut a screw with
twice the number of threads per inch as there are on the lead
screw.
It is then necessary to properly proportion the number of
teeth of the gears connecting screw and spindle in proportion to
the pitch of the lead screw and the pitch of the thread to be cut.
If the lead screw is, or has, six threads to the inch and it is desired
to cut a screw with twelve threads to the inch, then it is only
necessary to put a gear of twelve teeth on the screw and one
of six teeth on the spindle; then the latter will make twice as many
revolutions as the former and the threads per inch will be doubled.
Therefore, in “calculating change gears," as the machinists call
,
it, it is only necessary to put on the spindle a gear with a number
of teeth equal to the pitch of the screw and on the screw a gear
with a number of teeth equal to the number of threads to be cut.
This makes a nice easy rule to work by and to remember and

60
THE SCREW-CUTTING LATHE.
makes the smith independent of the table of change gears which
comes with the lathe and which is sometimes fastened to it on a
brass plate.
On the head end of some lathes is a swinging arm or bracket
which has a projecting stud for the reception of one of the change
gears. This part is known simply as the “stud,” and a gear is
.
placed upon it simply to make the lathe carriage travel in the
right direction. If a lathe cuts a right-hand screw with the stud
in use it will cut a left-hand thread with the stud gear removed.
The gear on the stud is also frequently necessary to connect the
gears on screw and spindle. In this case a second stud would
be needed to cut a thread of opposite hand.
SIMPLE AND COMPOUND CHANGE GEARS.
The diagrams herewith presented give an idea of the use of
one or more studs. Fig. 29 shows the lathe arranged for cutting
SPINDLE
30 TEETH
www
mm
STUD
mm
your
mm
now
o
SCREW
6 PITCH
40 TEETH
arrivare
Fig. 29-Change gears for cutting right-hand thread.
eight threads per inch, the arrangement being for right-hand
threads, while Fig. 30 shows the arrangement for left-hand
cutting. The gear on the spindle has thirty teeth; the No. 6
screw has a forty-tooth gear on it. To cut eight threads requires
gears in the ratio of six to eight, and as there cannot be
so few teeth we use gears having multiples of those numbers. As
regards teeth, we chance upon a factor of five and see how it works
gears of

THE SCREW-CUTTING LATHE.
61
out, as follows: Five times six are thirty teeth for the spindle,
and five times eight are forty for the screw. As gears having
the number of teeth thus called for are to be found they may be
put in place as shown. Or, we may use 36 and 48 gears, or 35
.
m
SPINDLE
30 TEETH
-STUD
man
mm
very
ma
more
name
©
SCREW
6 PITCH
STUD
STEETA VOI
rruvian
Fig. 30-Change Gears for Cutting Left-hand Threads.
and 56, or any multiple in number of teeth to the six and eight
called for by the screw and the thread to be cut.
Having placed the gears as noted above, it will be found
that they are not large enough to mesh with each other, there-
fore it is impossible to drive the lead screw with the gears
selected. To connect the gears it is necessary to use a third
gear which can be adjusted to mesh with the two described above.
This
gear
is shown on the stud, which is fastened to the lathe
headstock by means of a single bolt put through a slot in the
foot of stud, thus making an arrangement whereby the stud
gear can be pushed into any desired position in order to connect
the two gears.
When adjusting the stud take care that the gears do not
go too deeply in the mesh, or they will bind against each other.
The stud should be so adjusted that the gears all run easily and
smoothly. It makes no difference what gear is used on the stud,
as it does not enter in any way into the calculation for the pitch

62
THE SCREW-CUTTING LATHE.
of thread to be cut. If a left-hand thread is to be cut it may
be necessary to use two studs, as shown in Fig. 30, although when
there is a reverse in the lathe headstock the double stud business
is unnecessary, as the reversing can be done by means of the
reverse in question without the intervention of the second stud.
Some lathes are fitted with compound gearing for screw
cutting. This means that the stud carries two gears which, when
applied to a lathe, make the stud gear a factor in the screw
om
ма
SPINDLE
30 TEETH
woon
om
60 TEETH
សសស
20 TEETH
นนนน
mware
SCREW
48 TEETH
zowever
Fig. 31-Arrangement of Compound Change Gears.
cutting, something which is not the case when the gears are not
compounded upon the stud. Fig. 31 shows the manner in which
compound gears are arranged. In this the stud carries two gears
which are securely fastened together, and the number of threads
per inch which any pair of gears will cut must be multiplied or
divided by the ratio of the stud gears to each other.
"BOX” CHANGE GEARS.
The lathes noted above have each a complete set of change
gears permanently mounted on two shafts, something as shown
by Fig. 32, in which the upper shaft is the spindle of the lathe,
while the lower one represents the lead screw of the lathe. In
practice the gears are mounted on short shafts of their own and
connected by gears with the parts above mentioned, but the
diagram represents the principle of the operation.

THE SCREW-CUTTING LATHE.
63
A feather with a lump on it, shown at A, is made to slide
easily through all the gears, the lumps only engaging one at a
time, when the keyway in each happens to coincide with the key-
way in the shaft. The feather is moved along in its seat by
56
58
60
52
48
36
24
16
12
,SPINDLE
lo
SCREW
口​白​--
14
12
20
16
24
36
48
56
60
Fig. 32—Modern Gear Box Arrangement.
means of the handle B. When it is desired to use the gears 36
and 36 to cut a thread of No. 6 pitch, same as the lead screw,
then the lump on the feather is pushed into the 36-toothed gear
shown adjacent to it and the lathe is all ready, as far as the
gears are concerned, to cut the thread wanted. It is understood
that all the gears on the spindle are permanently fixed to that
shaft by means of a feather or by other means. Thus, if it is
desired to use gears 12 and 60 to cut a No. 30 thread, then the
knob A would be pushed into gear 12 and the lathe is ready.
If a thread of 1 1-6 pitch is wanted (which probably never will
be called for), the knob A is drawn into the 60 gear and the
thread cutting operation proceeds. The gears given in Fig. 32
are purely imaginary and are not as actually used on any lathe.
The threads cut by gears of the teeth given would not be very
practical, but the diagram serves the purpose of illustrating the
principle of the box change gears, for which purpose alone the
gears in question are intended.

64
THE SCREW-CUTTING LATHE.
There are several kinds of threads in use in the United
States, and it stands thè smith to become acquainted with the
standard threads and to work according to the same whenever
possible. The United States Standard thread should always be
60
Fig. 33—U. S. Standard Thread.
used on new work unless a square thread is necessary. Two or
three other threads are used to a considerable extent, and they
are given, in order that the smith may know how to shape them
when they are called for. The Standard V thread is often used
in the machine shop and it is formed by a simple V-shaped tool
60
Fig. 34-Standard V Thread.
as described in Chapter V. As shown by the accompanying dia-
gram, the tool must be ground to an angle of 60 degrees and the
gauge used for shaping the lathe center will answer admirably
for testing the shape of a thread tool, both for Standard V and
for United States Standard.
STANDARD THREADS.
The United States Standard thread differs from the Standard
V thread only in having the top and the bottom of the threads
cut off. Both these threads have an angle of 60 degrees. The
Standard V threads has a depth of 0.85 of the pitch. The United
States Standard thread has a depth of only 0.65 of the pitch, and
as one machinist aptly expressed the matter : “A roughing tool
for a V thread will just cut a Standard United States thread.”
It is one of the beauties of this thread that the tool stands up
a


THE SCREW-CUTTING LATHE.
65
well under the cut-much better than when cutting the V thread,
where the wearing off of the point of the tool is the one great
grievance the machinist has to overcome—and he could get
around the difficulty only by grinding off the point of the tool
so it would cut a flat top and bottom thread-United States
Standard in fact—then he would later sharpen up the tool and
cut out the bottom of the thread, thus making it into a Standard
V thread.
The Whitworth thread originated in England. It is practi-
cally the United States Standard thread with the top and bottom

530
275
Fig. 35-Whitworth Thread.
of the thread rounded. The angle of this thread is 55 degrees,
2772 degrees on either side of a vertical line drawn through the
thread. The depth is 0.75 the pitch, and the thread is, as stated,
rounded top and bottom. The tool is quite a hard one to grind
and the thread possesses little if any advantage over the United
States Standard thread.
4/20 kp
Fig. 36--The Square Thread.
The Square thread is made both single and double, and is
used for heavy work, like presses and similar machinery. The
angle is square and the depth equals half the pitch plus 0.01" to
0.03" clearance. The width between threads equals half the pitch
plus clearance. When cut double it is a quick-acting thread. An
ordinary cutting-off tool with a good deal of side clearance may
be used for cutting this thread.

66
THE SCREW-CUTTING LATHE.
The Powell thread is much like the Square thread, with
certain characteristics of the Standard United States thread. It
is used for the same purposes as the square thread, and may be
Fig. 37—The Powell Thread.
cut with the same tool by merely grinding off the corners of the
tool to the proper angle. The depth of this thread equals half
pitch plus clearance. The width of thread at top is 0.37 of the
pitch and the space at the bottom is also 0.37 of the pitch.
TAKING ROUGHING AND FINISHING CUTS.
Having set up the change gears and made a tool in accord-
ance with the direction given above and in previous chapters,
start the lathe and run forward the tool until its point barely
touches the work. Stop the lathe without moving the tool and
apply to the slide rest carriage a sort of clamp which will be
found among the furnishings of the lathe. The clamp has a
set-screw by means of which the carriage or the cross-feed may
be permitted to advance more or less by slacking off on the set-
screw with the fingers. Bring the screw to bear, clamp the
casting, and see that the point of the tool barely touches the
work, which, by the way, must be so held that it has no lost
motion back or forth. Tie or wedge the dog in such a manner
that the work cannot move forward or back without the lathe-
spindle going with it.
There are three ways of starting a thread. Either the
cutting may get into the metal on a gradual slant or taper, or a
hole may be drilled in the work at either end of the thread, or a
portion of the work may be turned down at either end of the
proposed thread to a diameter equal to that of the bottom of the
thread, as found from the description of each thread given above.
This is the most satisfactory way and should be employed when-
ever possible. The turned down portion of the work where a
thread stops is technically known as a “run-off.”

THE SCREW-CUTTING LATHE.
67
Start the lathe and run the tool the entire length of the
thread blank, setting the tool forward until it takes a slight cut,
then bring the set-screw against the cross-feed so the tool can
go no deeper. Arrived at the end of the cut, screw the tool back
clear of the work. If a run-off is used there is time enough for
this, but if a drilled hole stops the thread it will be necessary to
stop the lathe before the hole is reached and to turn the lathe
by hand by means of the belt a few inches until the tool enters
the drilled hole, when the tool is to be moved back as above
described.
When the thread tapers into and out of the work it is
necessary to run the cross-feed back by hand at the instant when
the tool reaches the end of the cut. This requires nice judgment
on the part of the latheman, and the beginner should practice
with a generous run-off at either end of the screw until he “gets
the hang” of the new school-house. Having arrived at the end
of the thread, with the tool run back, reverse the lathe and let the
lead screw run the carriage back to the beginning of the thread.
While this is being done screw back the little set-screw just the
depth of another cut with the tool. A little experience will
quickly tell how much, and a few broken tools or screws twisted
from between the lathe centers will indicate the proficiency of the
learner.
“CATCHING THREADS VS. RUNNING THE CARRIAGE BACK."
It requires a very considerable length of time for the lathe
carriage to be screwed back after each cut, and the lathesman
will soon cast about for means of saving some of the time thus
lost. As he becomes expert with the lathe he will find that in
cutting some threads the nut may be opened by unclamping, the
lathe carriage run quickly back by hand in a fraction of the time
required by the screw and the nut clamped in again, picking up
or "catching" the thread exactly as if the lathe had been run back
by hand. This is true when the thread being cut is the same in
pitch as the lead screw. It is aļso true with some multiple pitches
of that screw, but there are certain threads which cannot be
caught up without some special maneuvering. For instance, to
cut a No. 7 thread and catch the screw just right each time
would require considerable study and take longer than to run the
carriage back by reversing the lathe.

68
THE SCREW-CUTTING LATHE.
A quick and sure way of catching any thread is as follows:
Make a mark on the large pulley or on the flange between that
pulley and the gear on spindle. Bring the mark to coincide with
another mark on the lathe head, and at the same time rig a stop
which will prevent the carriage from being moved any farther
toward the headstock. It is evident that with the spindle and
carriage in this position the nut can always be locked in the same
place, therefore cut to the end of the screw, unlock the nut, run
carriage back by hand to the stop, stop the lathe on the two
marks, throw in the nut and go ahead with another cut on the
thread.

CHAPTER IX.
INTERNAL TURNING OR BORING.
A general idea of the form of tool for boring was given
in Chapter V and the simple tools therefor were illustrated. Bor-
ing, in the accepted meaning among machinists, means cutting
metal off the inside of a cylinder, while "turning” means the
cutting of metal off the outside of the cylindrical shape or body.
But in actual work boring is very seldom done with a tool shaped
like
any of those illustrated in Chapter V. It is only in job work,
where a single hole is to be made, that boring with a lathe tool
is resorted to. And even then the lathe tool is used if no other
tool can be found with which to do the work.
But as the smith proposes to do little else except job work it
is in order to tell how to do a good job of boring with ordinary
lathe tools. To begin with, always use as large a tool as can
be gotten into the hole to be bored. Never make use of a slim
tool when a heavy one can be used as well as not. Above all
things, never, under any circumstances, forge down or alter over
a standard tool to do some special job. Have some tools for that
purpose alone, and even then, whenever possible, forge up a new
tool for the job in hand and then make that tool one of the
standard ones, for never yet was a lathe tool made but what it will
come in very handy: in fact, be just the thing for some similar
work.
The more lathe tools the better. They are a very good in-
vestment, and money put into tools of any kind is always money
well invested. Don't begrudge the money you spend for tools.
In setting a lathe tool in the tool-post always place it in such
a manner that when it springs under the strain of a cut it will
bear against the side of the tool-post. This matter was fully
described and explained in Chapter V also, and inside tools as
well as those for outside turning should always be placed against
both sides of the tool-post slot, and the tool-post twisted around
until the desired position of tool has been reached.
The clearance necessary in a boring tool varies with the
69

70
THE SCREW-CUTTING LATHE.
diameter of the hole to be bored. Were the size of the tool used
always in proportion to the diameter of the hole to be bored
there would be no difference in the angle of clearance necessary,
but as the tool selected should, as stated, be as large as can be
kb
cal
А
B
Fig. 38-Clearance of Boring Tools.
used in the hole, the clearance must necessarily vary as shown
by Fig. 38, where the tool fills more of the small hole at B than
it does of the large hole at A, whereupon the machinist grinds
back the lower portion of the tool in order to get it into the hole
in the proper position to do good cutting. Should the smith-
machinist go to the trouble of making up tools for small holes
and other tools for large holes, then he can grind the clearance
of each tool on the same angle as shown at a, in sketch A, merely
grinding the clearance of the tool on a circle instead of to a
straight line as shown by both sketches A and B. But the smith
machinist does not like to do this, therefore he grinds more
clearance for the tool in the small hole and lets it go at that.
USE OF THE CHUCK AND THE STEADY REST.
As a usual thing it is not possible to do a job of boring
with the work suspended between centers. On very large shallow
holes this may be possible, but it is not practical one time in a
hundred, therefore the tail-center must be dispensed with when
boring is to be done, and the work must be held in the lathe in
some other manner than between centers. Usually the chuck
does duty in this business, and when the work is of considerable
length the steady rest must be brought into use also.
Suppose it be necessary to bore out a shaft collar from
I 15-16 to 2 3-16 inches. The first thing is to chuck the collar.

THE SCREW-CUTTING LATHE.
71
For this purpose, if the lathe has been fitted with a chuck, remove
the small face-plate which is used to drive dogs when turning
ordinary work, and put in place the chuck, screwing it on the
spindle as far as it will go. Some men have the very bad habit
of putting on a chuck by starting the spindle, no matter whether
the belt happens to be on a fast or on a slow speed—and letting
the chuck screw home and fetch up with a jerk at the end of the
threaded portion of the spindle. This is bad enough when putting
on the little face-plate used for dog driving, but when a heavy
plate or a big chuck is thus put in place there is danger of seri-
ously straining the spindle, particularly if the belt happens to
be on a fast speed.
A good way to put on a chuck is to hold it in place with
the right hand and turn the spindle with the left hand by means
of the belt until the chuck has been screwed home. Or a careful
man may hold the chuck with one hand and start the lathe on a
slow speed with the other hand, making sure to stop just before
the chuck goes over the last thread, which should be screwed up
by hand. Another abuse of face-plate or chuck, which should be
avoided, is to start them off by putting a piece of iron in position
for the jaw of the chuck to strike against, and then giving the
belt a pull, catching the chuck on the jaw as above, stopping it
dead, and letting the momentum of the lathe spindle and its load
of pulleys and back gears start the chuck or plate. This is very
bad practice and should always be avoided. Start the chuck by
means of a lever placed between the jaws of the chuck, or
between two bolts placed in slots or holes in the face-plate. Pull
on the lever and the plate or chuck will start. If it should chance
to be on extra tight, throw in the back-gear and put the belt on the
largest pulley. Thus rigged, there will be little difficulty in hold-
ing the spindle against the pull of the lever, the teeth of the back-
gear are strong enough to stand the pull provided that the step
pulley be not locked to the back-gear, which is one of the surest
ways of breaking the teeth out of one or both of the
ing the spindle by means of the back-gears and the belt permits
the spindle to yield a little when the lever strain comes on,
through a slight giving of the belt:
Having put the chuck in place, take a grip on the outside of
the collar, making sure that the jaws of the chuck (if an inde-
pendent chuck be used) are all the same distance from the center,
gears. Hold-

72
THE SCREW-CUTTING LATHE.
which is determined by their distance from the outer edge of
the chuck, or from any one of the concentric rings with which
the face of the chuck is finished. These rings are for the purpose
of centering the jaws whenever necessary, and they should
always be made use of when putting work into the chuck. Of
course if the chuck be a universal one, the centering business can
be dispensed with and it is only necessary to put the work in
place and screw up the chuck. Even then the work should be
tested to see if it be centered truly, for sometimes there are
lumps or projections on the surface which prevent the work
from centering itself exactly.
When such is found to be the case, it is necessary to pack
under one or more of the chuck jaws, using thin metal strips
or thick paper, until a bit of chalk held against the work while
it is revolving will make a mark entirely around the surface. In
chucking the collar above mentioned there were one or two rough
places in its surface where a hammer had been used some time
or other, and one of these places coming under the jaw of a
universal chuck, threw the work out of round a trifle. It was
not very much, but enough to spoil the accuracy of the work
when a good job was necessary.
By holding a bit of chalk against the surface of the work
the high places can be easily detected and the chuck shifted
accordingly.
ACCURATE CENTERING.
It is not possible to center as accurately as sometimes is
necessary by using the chalk method, hence for extra nice work
an "indicator" should be used which will magnify the excentricity
of the work. Such an indicator of the "home-made” variety is
shown by Fig. 39. It is a very simple device and is easily made.
Its principal parts are: A bar or shank, D, which fits into the
tool-post the same as a tool would be placed, and the bar is made
with a split end, hollowed out as shown by detail E, to receive the
ball which is formed upon pointer C at B. The enlargement B
is placed in the hollow cavity in bar D, and the two act as a ball
and socket joint in permitting free though limited motion of
the pointer C, which, when in use, is placed with its lower end
against the object to be centered, as shown at A. When this
is done the revolution of the work, should there be any inequali-

THE SCREW-CUTTING LATHE.
73
ties in the surface thereof, causes the short arm to vibrate with
the inequalities, and the motion being greatly magnified by the
B
E
Fig. 39-Centering Indicator.
long arm C, is rendered visible in a marked degree by the vibra-
tions.
The piece to be chucked being put in as close as the eye
can determine, the pointer is placed in position and the lathe
started on a very slow speed. If the work be the least out of
truth, the long arm C will rise and fall with every revolution of
the work and the workman has only to note the position of the
arm and move one of the jaws of the chuck accordingly. A very
little practice with one of these indicators will enable a man to
quickly chuck a round piece of material with an accuracy which
could never be even approached by the best lathesman in the
country working without the indicator.
The indicator may be easily made by any blacksmith and its
cost will be but a trifle, while its value is great. The device can be
applied to inside as well as outside surfaces. In that case it would
be made to work in the top of the hole, while for exterior work it
works as shown, against the bottom of the object.
To true up work when an independent chuck is used—and by
independent is meant that the three or four jaws of a clutch all
work independent of each other, each being controlled by a
separate screw which is set up, as required, by means of a wrench
which fits all the screws. The universal clutch, on the contrary,
has as many screws as it has jaws, of course, but these screws are
all connected by means of a large connecting gear so that turning
up any one of the screws causes all of them to advance an equal
distance.
Some chucks, however, do not have any screws. Instead the

74
THE SCREW-CUTTING LATHE.
jaws are advanced by a sort of spiral which is placed just inside
the face of the chuck and which may be rotated from either
one of several places in the chuck. Other universal chucks
have a shell which screws over the front end of the chuck and
carries with it the jaws which hold the work in place. Both the
independent and the universal chucks have their good points,
,
and both should be provided as soon as possible by the smith-
machinist who desires to do good work and lots of it at a low
price.
The large face-plate may be and should be made into a chuck
by means of four movable jaws which may be bolted at will to the
face of the chuck, forming a large independent chuck which is
very useful in holding pulleys and similar work which will barely
swing above the lathe bed. Bear in mind that the jaws of all
good chucks should be made to reverse so as to hold a ring or
pulley from the inside of the rim as well as from the outside
thereof. Many good chucks are designed with this end in view.
In selecting chucks pick out one of this kind, also see that it is
adjustable for wear and that it is strong and well constructed.
SETTING THE STEADY REST FOR BORING.
Place the work in the chuck as directed above, supporting
it entirely by that means, provided the work is not so long as to
pull out of the grip of the chuck by its own weight. Having made
the far end of the work (the end farthest from the chuck) run
as true as possible, proceed to put the steady rest in position as
close to the end of the work as possible, and make sure that the
bearers of the rest lie fair against the work before they are tight-
ened into place.
The surface of the work must be clean and smooth where
the steady rest is to bear, otherwise good work is impossible
under any condition. It is not possible to true up work in the
steady rest by means of the center indicator, for this tool will
not work unless the work be held in the lathe entirely by the
spindle and its attachments (face-plates, chuck, etc.). Keep the
bearers of the steady rest well oiled at all times when the lathe
is running. The least stick, chatter or jumping between the
work and the steady rest and good-bye to the possibility of
decent work.
When an object too long to be first supported and trued up

THE SCREW-CUTTING LATHE.
75
by and from the face-plate or chuck has to be bored, then it is
time to rig up some other means of holding the work in the lathe.
Bear in mind that a boring tool must project from the tool-post,
a distance greater than the length or depth of the hole to be
bored, and it will be seen that the limit in boring with an internal
lathe tool is reached very quickly. Not over eight or ten inches
.
overhang should be permitted in any lathe a smith is likely to
have in his shop.
When a greater depth than 10 inches must be bored, the
process becomes what is known as “cylinder boring” and the
work is made fast to the slide rest of the lathe and is moved
forward against the tool by the same feed which moves the tool
in ordinary outside turning. For this work a special tool is
required which is known as a “boring bar.”
THE BORING BAR AND ITS USE.
A boring bar, as usually made, consists of a piece of heavy
shafting the length of which is two and one-half times that of
the hole to be bored. Fig. 40 gives a general idea of a boring
bar of this kind. Its diameter is I 15-16 inches, and the length
about three feet. A hole over 22 inches can be bored with this
tool, provided it is large enough to allow a portion of the tail
spindle to enter, in which case that portion of the spindle which
Fig. 40-Boring Bar.
enters the hole can be considered as a part of the length of the
boring bar, and must be so considered when figuring the length
of bar necessary to bore a hole of given depth.
The tool is simply a piece of round tool steel, ground to
the required shape and tempered. It is held in place by means
of a set screw which is shown at A. The bar is placed between
the lathe centers and is rotated by means of a dog in exactly the
same nianner as if it were put in the lathe to be turned. In

76
THE SCREW-CUTTING LATHE.
fact, the entire operation is exactly the reverse of turning, for
the tool is placed between centers while the work is fastened to
the slide rest.
Still another form of boring tool is shown by Fig. 41. This
is technically known as a "chucking tool” and really belongs more
to the drill and reamer tribe than to the boring family. As
shown by the engraving, this tool is a good deal like the one
presented by Fig. 40, save that the cutter is close to one end
instead of being in the middle, and usually fastened by a screw
in the end of the bar. Fig. 41 gives a pretty good idea of this
tool, and the method of using it.
THE "CHUCKING” DRILL BORING BAR.
The lathe chuck or face plate is represented by A, and the
cylinder to be bored is shown at B, while C is the boring bar, D
the cutter and E is a wrench to prevent the boring bar from
turning around. A rest to support the wrench is shown at E,
while G represents the tail spindle of the lathe. To operate the
&
D
<
с
ç
E
Fig. 41-"Chuck Drill” Rigging.
device, the work is first chucked in the ordinary manner and
supported by the steady rest, if necessary. The tool is placed
central in the bar and screwed fast, then the wrench is slipped on
the bar, which is placed against the tail spindle of the lathe which
enters a center made to receive it. The wrench E, may either
be a bit of flat iron bent up to fit the square of the bar,
or made with a square hole worked through it, is to prevent the

THE SCREW-CUTTING LATHE.
77
bar C from revolving with the work. The wrench bears upon
the rest F, which may either be the ordinary wrench of the drill
lathe or it may be a piece of iron placed in the tool-post and
turned lengthwise of the lathe. In many instances the wrench
is made to be held directly in the tool-post, in which case it stands
at right angles to the lathe bed.
As shown by the engraving above referred to, and more
plainly by the detail, Fig. 37, the leading end of the cutter is
beveled off a little and this bevel will become greater as the tool
is ground time after time. The center which receives a projec-
tion in the end of the boring bar is plainly shown at A and C,
Fig. 42, while B shows how the clearance is provided for. To
make these cutters they are usually turned
in the lathe in order to make the center
come true, after which they are ground or
filed off to give the necessary clearance.
This tool, once started in a cut, will
go straight through the work with very
little variation from the direction in which
Fig. 42—"Chuck Drill"
the bar is pointed. A straight and very true
hole can be depended upon when this tool is used, provided the tool
is kept in good order and ground evenly when the least bit dull.
These tools, for holes up to 4 inches in diameter, are usually made
of steel 1/2 x 1 inch for the larger sizes, and 38 x 1 inch for the
smaller sizes. The bar C, Fig. 41, is usually made of 1-inch
square steel.
PROPER SETTING OF BORING TOOLS.
The proper setting of the tool above shown needs no care,
as it is automatic in that direction and centers itself. It does,
however, point to the proper way of setting all internal tools,
that is, to have them exactly radial to the center line of the
object to be acted upon.
B
A
с
Cutter.
CUTTING INTERNAL THREADS.
In internal threading the operations are the same as when
boring with the overhanging tool, but modified by the practice of
external threading. In fact, internal thread cutting is a modifi-
cation of the two operations above noted. There is one necessary
requirement which must never be overlooked, and that is : the
making of a generous "run-off” at the bottom end of the proposed

78
THE SCREW-CUTTING LATHE.
thread into which cavity the tool can pass when it reaches the
end of its travel. No good internal thread can be cut in the
lathe without first making the run-off mentioned.
REAMING IN THE LATHE.
It is frequently necessary or desirable to ream holes which
have been bored or drilled. To do this, either use one of the
cutters shown by Fig. 42 or use a fluted reamer, placing the
squared end against the tail center, and holding the reamer with
a wrench fitted to the squared shank. The great danger in
reaming in the lathe is in the tendency of the reamer to become
clogged as it lies down and the cuttings cannot drop out as they
do when reaming vertically. However, with a little care in
feeding up the reamer, and with frequent stoppings to clean out
the cuttings, excellent results can be obtained by reaming in the
lathe as described.

CHAPTER X.
THE FACE-PLATE.
The face-plate of a lathe has two principal uses: First, for
imparting motion from lathe spindle to whatever work may be
between the lathe centers. That is one office of the face-plate.
The other use is for supporting work which is large in diameter
and usually of little length. For the two purposes above noted,
two face-plates are usually sent out with a lathe—sometimes
three—a small plate with a slot for the tail of a dog, a large plate
as big as can be swung over the ways of the lathe and a driving
face-plate. These articles are usually about as shown by Figs.
-
43, 44, 45, 46. The small face-plate, Fig. 43, has a slot cut in one
side from the edge clear down to the hub. This slot is for the
tail of the dog which is to drive the
work when between-centers jobs are
being done. The small four-arm face-
plate, Fig. 44, is for the same purpose
with the additional use of permitting
small work to be bolted on with two
or four bolts. This is a very handy
Fig. 43-Small Slotted Face-
feature when some jobs have to be
done and it saves drilling holes in a solid face-plate to accommo-
date the special work.
For large work, the big face-plate, Fig.
45, is indispensable. All sorts of jobs may
be clamped upon it by the use of some bolts
and a few pieces of flat iron, as will be des-
cribed later in this chapter. This face-plate
is made as large as will swing in the lathe and
great care should be taken that it does not
Fig. 44-Driving Face-
get abused by tool marks, chisel cuts or other
careless earmarks of shiftlessness. Great care should be taken
when putting the large face-plate on the spindle, that the latter is
not bent by careless screwing on of the heavy face-plate. As stated
in a previous chapter, great care should be taken in screwing a
Plate.
Plate.
79

80
THE SCREW-CUTTING LATHE.
heavy chuck in place, for, if belt power be used to screw on the
chuck or face-plate, it will usually bring up in place with a jerk,
which, if it does not spring the spindle, will certainly cause the
chuck to stick so tight on the spindle that it is very hard work to
get the chuck off again. Furthermore, screwing the plate upon the
1
DJ
Fig. 45-Large Face-Plate.
spindle excessively tight is very likely to cause the plate to wobble
or otherwise run untrue. It is always best to pull on the belt
with the hard, when a large face-plate or chuck is being screwed
home, and just barely bring the plate hub against the shoulder
of the spindle. A plate put on every time in this manner will
always run true and the spindle of the lathe will stay in fine con-
dition a long time.
The "smith-machinist” will do well to get up a pattern and
make up several small face-plates like Fig. 43. These plates
are very handy things to have, and they may be made into special
chucks for some kinds of work which the smith finds will come
along frequently. A pattern of the large plate is also desirable,
for a very handy independent chuck can be made up on one of
the large plates, which once rigged should be kept for a chuck
and not used for anything else.
When putting on a face-plate or a chuck, certain things
should always be done, among which are: Be sure to remove

THE SCREW-CUTTING LATHE.
81
the center from the spindle whenever any job is to be done which
does not require the center for the support of the work; also when
drilling is to be done by means of a drill attached to the tool-
post or to the tail stock, be sure to remove the center from the
spindle. This center is technically known as the “live” center to
distinguish it from the center in the tail spindle which is known
as the “dead” center. As soon as the center is removed stuff a
wad of waste into the taper hole and let that waste stay there
until the center is to be put in again. This keeps all the metal
chips out of the hole and makes easy the replacing of the center,
for it is only necessary to pull out the waste and the hole is bound
to be clean and all ready for the insertion of the center.
The spindle is hollow, so always keep a rod handy for pok-
ing out centers, drills, etc. Forge a head 2 inches in diameter
on one end of the rod and let the rod lie in the spindle unless its
rattle when the lathe is running proves to be disturbing. With
the rod in question the wad of waste can be pushed out and the
spindle is all ready for the center, without any time being spent
digging out dirt or scale or lathe chips.
"CHUCKING" WORK IN THE LATHE.
The machinist has some queer technical terms which he uses
in his business and the smith has a few of his own which are
as strange to the machinist as machinist terms are to the smith.
For instance, everything which is put into the lathe to be oper-
ated upon is known as "work,” and if the object is bolted to the
face-plate it is said to be "chucked.” When a hole in the "work”
is to be cut out larger by means of a tool in the tool-post the
operation is called "boring.” If a hole is drilled to any given
diameter, and the machinist passes another drill a size larger
through the hole, the second operation is not "drilling," instead,
it is technically known as "reaming," for the larger drill merely
reams a little off the walls of the hole already made.
that in the course of work with the lathe it becomes
necessary to fit up some new shafting and pulleys, and that a
certain pulley could be used provided it had a little larger bore.
The sizes of shafting run 1-16 inch less than even inches and half
inches, for instance, 15-16 inch, 1 7-16 inch, I 15-16 inch, 2 7-16
inch, 2 15-16 inch, etc. The reason for this strange size is that
when square shafting was abandoned only forty years ago, and
Suppose

82
THE SCREW-CUTTING LATHE.
round shafting came into use, every machine shop had to make
its own shafting, so they bought 11/2-inch, 2-inch, 27/2-inch iron,
etc., and turned their own shafting. It required 1-16 inch of metal
for the finishing process, hence the odd sizes of shafting which
remain in use to-day and which are here to stay.
But suppose that a 22 x 8 x 1 7-16 inch pulley needed to have
the hole in the hub increased to i 15-16 inch. The first operation
will be, as the machinist expresses it, to "get it in the lathe.”
The machinist never "puts” a thing in the lathe; he "gets” it
there. And about that pulley: in describing any pulley, always
state the diameter first, then give the width of face, next the
diameter of bore of hub, then state whether the face is flat or
crowned; lastly, tell whether the pulley is set-screwed or key-
seated, or both. In making a schedule of pulleys it will run
something as follows:
I pulley 22 x 8 x 1 7-16 inches C. K. S. (crowned face, key-
seated).
ī pulley 22 x 8 x 1 7-16 F. S. S. (flat face, set-screwed).
pulley 22 x 8 x I 7-16 inches C. K. S. S. & K. (crown face,
key seat and set-screwed and key).
2 pulleys 22 x 8 x 1 7-16 inches C. S. S. T. & L. (crowned,
set-screwed, tight and loose).
In this description the statement that the pulleys are crowned
face is entirely unnecessary, for the reason that tight and loose
pulleys for a shifting belt are invariably made crowned face.
Two ordinary pulleys will not answer for tight and loose pulleys,
as the hub of the loose pulley must be in length equal to the
width of face of pulley at least, and as much longer as possible,
depending upon the diameter of shaft. In all cases the length
of a loose pulley hub should be four times the diameter of the
shaft. The above description, while not relating strictly to the
lathe and its use, is something which the machinist-smith should
know, and as the best time to learn new things is the present
time and minute, therefore the facts are stated at this time,
somewhat out of their logical precedence.
I
CHUCKING A PULLEY.
The object in "chucking” a pulley is to fasten it to the face-
plate of the lathe in such position that the rim of the pulley will

THE SCREW-CUTTING LATHE.
83
run perfectly true, which means that each and every portion of
the pulley face is the same distance from the center of the pulley.
If there is at hand a short piece of shaft with a center at each
end thereof the chucking problem is an easy one and all that is
necessary is to put the bit of shaft between centers with the pulley
shaft upon it. Then slide the pulley up to the face-plate and
clamp the pully thereto by means of several bolts. Fig. 46 will
give an idea of the way to bolt the pulley.
B
CH
OA
o
Fig. 46-Chucking a Pulley.
Three or four bolts may be used (the illustration shows
three), each long enough to go through the face-plate with a nut
and washer on the back thereof, and to project about one inch in
front of the pulley. The bolts, B, B, B, are passed through the
iron straps, A, A, A, which may be 2 inches wide, 34 inch thick,
and 6 to 8 inches long, with a hole drilled through large enough
to easily pass one of the bolts. At C, C, C are shown pieces of
material in length equal to the width of the pulley face. Hard-
wood will answer very well, or short pieces of bar iron may be
used. Every lathe should have a number of such pieces, sawed off
square, and a certain number, say four of each, cut to the same
length. A set may be made 4 inches long, another set 5 inches
long, another 6 inches, and so on, as required. One-inch square
iron of fair quality is cheap, and lengths may be cut off as needed

84
THE SCREW-CUTTING LATHE.
until a full graduated series of lengths has been provided.
If you have a set of 8-inch bars, and require some 7-inch, do not
cut off the 8-inch ones. Instead, just cut off another complete
set of the required length and put them in the tool rack when
done with them. They will come in handy, time after time. The
first use pays for them, the next and succeeding uses is clear
profit.
When a very heavy pulley is to be chucked considerable more
holding power may be obtained from the bolts by making the
holes in the clamp-bars, A, Fig. 46, in such a manner that the
bolts come close to the pulley rim. About double the holding
power is obtained from the bolts by, so doing.
After the pulley is clamped fast as described above, push
back the tail-stock and remove the short piece of shaft from
the pulley. Also remove the head center, plug the hole with a
wad of waste, and go ahead with the boring-out process. When
there is no piece of shaft available, place the pulley as near cen-
tral as possible, then proceed to center it as directed in Chapter
IV, using the chalk or the center indicator, if one is at hand.
CHUCKS VS. FACE-PLATES.
A large chuck is a fine thing for the smith to have in his
little machine shop, but chucks are very expensive things and not
one smith in one hundred will feel able to put up $200 or so for
a large chuck. Such being the case, an excellent substitute for a
large chuck may be made by the smith for one-tenth the sum
named. Procure or make another large casting for a face-plate,
similar to that shown by Fig. 45, except that there shall be no
slots made or cast in it. The face of the plate shall be turned
smooth and true, then drill rows of holes, as shown by Fig. 47,
also draw circle within circle on the face until the entire surface
is covered with circles one-half inch apart.
The circles are very handy when chucking anything that
may have to be put into the lathe, as the face of the object need
only be brought to one of the circles, or equally distant all around
from one of the circles, to be approximately centered; quite near
enough to begin on with the chalk or indicator.
To make the very handy chuck shown by the preceding
figure it is only necessary, in addition to the face-plate, to make
up four bolts and screws, as shown by Fig. 47. For a 24-inch

THE SCREW-CUTTING LATHE.
85
face-plate the head of the bolt may be 1/2 inches square and the
bolt should be about 1 inch in diameter, or to fit the holes in the
face-plate. The screws should be about 3 inches long, 34 inch
in diameter, and the threads should be removed for at least 1/2
o
Fig. 47-Large Independent Chuck.
inch at the point to prevent upsetting of the screw in such a
manner that it cannot readily be backed out of its nut. Some-
times a very fine adjustment is needed, and to obtain it a check-
nut may be placed on each square nut next to the point of the
screw. By setting up the check-nut a little slack may be taken
out of the thread in the nut and a much finer adjustment given to
the work than is possible with the plain screws alone. The check-
nut shown may be omitted if there is no room for it, or, if used
for locking only, it may be placed between the nut and the
head of the screw.
It is usual when using a face-plate chuck of this kind, and
it is well with any other chuck, to reinforce the holding power
of the adjusting screws (Fig. 47) by two or three bolts and
clamps to hold the work against the face-plate and to furnish the
necessary driving power, thereby relieving the adjusting screws
of that work, making it necessary for them to hold the side
adjustment of the work only.

86
THE SCREW-CUTTING LATHE.
The chuck bolts shown may be used either outside or inside
the work as desired, by simply reversing them and pointing the
screws in the other direction. By thus arranging the bolts a
pulley fully as large as the face-plate may be chucked with per-
fect ease, the adjusting screws bearing outward from the inside
of the pulley-rim, instead of inward, as shown by Fig. 47. For
holding irregular work in the lathe these bolts leave nothing to
be desired, and by means of these adjusters and the clamp bolts
it is a mighty obstinate bit of work which cannot be held to the
face-plate of a lathe.
CHUCKING WITH WOODEN SHAPES.
When very peculiar shapes require chucking, particularly
where there is no flat surface to work from, it is sometimes
necessary to use a piece of wood between the work and the face-
plate. Proceed to select a bit of wood-soft wood if only one
or two pieces alike are to be chucked and hardwood if a con-
siderable number of pieces of work are to be operated upon-
then proceed to cut out such portions of the wood as will let the
shapes lie upon the face-plate in the position in which it is re-
quired to bore the hole. When the wood has been fitted place the
work in place and hold by bolting, or by the use of clips in the
way already described. There is no end to the way in which odd-
shaped pieces of metal may be fastened and placed in position
for working in the lathe. A little ingenuity is all that is required
by the smith to handle any case of this kind which may come
along.
Sometimes, for very obstinate cases, calcined plaster is used
for holding the work in place. In this case the plaster (ordinary
plaster of paris) is mixed pretty thin with water and, after the
metal has been blocked, propped or wedged in position, the plaster
is poured over (and under) the work, giving it a perfect bearing
upon the face-plate. This is an excellent way to support thin
metal plates when work is to be done on them in the lathe. The
plaster will hold them without a tremor when the tool comes
along.
When it is desirable to hold very small pieces of metal in the
lathe and to fasten them firmly and quickly, also to be able to
just as quickly remove the pieces from the lathe, a face-plate
covering with sealing wax will do the business. Coat the wax

THE SCREW-CUTTING LATHE.
87
over the plate as needed, letting it get from 1/8 to 12 inch deep
as necessary, keeping the plate warm by means of a hot iron, a
lamp or some other arrangement, then press the piece to be
chucked right into the wax until it is in the position desired as
regards being central, etc.
A most excellent way of centering small pieces which are
to be held as above is to heat the wax just hot enough to stick
firmly to face-plate and to the work, and yet allow the latter to be
moved slowly in any direction. Then, while the wax is in the
condition above noted, press the work one way or another until
it is centered as desired. If it be a small finished flange, which
it was not thought best to run the risk of scratching or springing
in a chuck, and there was a hub or other projection, just stick
it on the wax, then run the slide-rest up to the work, clamp the
tool-post, and with a stick or a smooth tool hold the work in
the desired position while the wax cools, the lathe revolving
all the time while the wax is cooling.
The above-described method of chucking is frequently used
by watch repairers for holding in the lathe small wheels or gears
with the pinions and shafts all in place. The method is just as
useful to the machinist as to the watchmaker, and there is no
limit to the size of objects which may be chucked in the manner
described. To remove the work heat the wax and the metal will
readily separate from it. Frequently a smart tap with a hammer
will free the entire object from the wax. If some of the wax
adheres to the metal a little gasoline and a brush will quickly
clean the metal surface.

CHAPTER XI.
BORING IN THE LATHE.
A short description of the boring bar and its use was given
in Chapter IX, and a simple form of boring bar was shown by Fig.
40. Several sizes and lengths of this useful tool should be made
up by the smith-machinist and will be found very useful and
paying investments. The bar shown by Fig. 40 requires a ham-
mer adjustment when the cutting tool has to be set out to a
greater diameter. For most kinds of work this form of adjust-
ment will answer every purpose, but when dealing with very
large bars a better form of tool adjustment is necessary, in wnich
case a collar may be placed over the tool as shown by Fig. 48
and the tool forced out at will by means of the set-screw shown
in the engraving in question.
An ordinary collar is used, the usual set-screw being replaced
by one long enough to reach through the shaft as far as the cut-
ting tool. It is well to make the collar at the same time the
shaft is made so that the hole for the tool may be drilled with the
Fig. 48 - Boring Bar Tool Adjustment.
collar in place. Drill the tool hole through one side of the collar
and completely through the boring bar, but not through the re-
maining side of the collar. Instead, finish this hole with a "tap-
ping drill”—that is, a drill which is just large enough to receive
the tap for a set-screw of the required size. If an ordinary
-
88

THE SCREW-CUTTING LATHE.
89
finished collar is used the holes above mentioned may be drilled
at right angles to the regular set-screw hole, but if the collar
be made after the boring bar has been finished, a little figuring
must be done to get the tool hole in collar exactly in line with
the tool hole in the boring bar.
An ordinary cast iron collar may be used as described
above, but it makes a pretty brittle member and it is much better
to forge a good steel collar and bore, turn and drill it to fit
the particular boring bar it is intended for. These adjusting
collars can only be used on holes of considerable size where there
is room enough to admit the boring bar and collar also, but for
making large holes these collars will be found most excellent, not
only for tool adjustment to a nicety, but for supporting the tool
as well. The collar provides a bearing for the tool much closer
to the cutting edge than is possible without the collar.
BORING SMALL CYLINDERS.
The smith-machinist will frequently be called upon to repair
small cylinders for steam engines, pumps and possibly for auto-
mobiles, but beware of the latter work unless it is done by the
hour, and under no circumstances assume the risk of making
certain automobile repairs for a lump sum. At present automo-
biling is a luxury, therefore let repairs to those machines be
a luxury also, for those who own autos are, or should
be, abundantly able to pay well for repairs.
Certain engines in use for small power units have their
valves made in the form of pistons, operating in cylinders of less
diameter than the cylinder of the engine. Whenever valves of
this type become leaky, about the only remedy is to bore out the
valve cylinder to a diameter which will remove all the large places
and leave a true cylinder in place of the locally worn mechanism.
The same is true with certain pump cylinders, both power and
hand pumps, some types of which have a small, short iron
cylinder in which the lifting valve moves.
MOUNTING THE CYLINDER.
A cylinder of this kind, as well as a valve cylinder, or even
the main cylinder of a small engine, may best be made true in-
side by reboring in the lathe. If the character of the cylinder
is such that it cannot well be fastened to the face-plate of the

90
THE SCREW-CUTTING LATHE.
lathe, then mount it on the slide rest and bore as hereinafter de-
scribed.
Fig. 49 shows one of the many ways of mounting a small
cylinder upon the face-plate of a lathe. Bolts and bands are all
that are necessary, but considerable “know-how” is needed to get
the cylinder in just the right position. Aside from the bolting
there is the turning of the cylinder in two ways, so that the bore
Fig. 49—Mounting Cylinder on Face Plate.
of the cylinder runs true and so that the
true and so that the flanges do not
vibrate endwise of the cylinder in the least.
. After the
cylinder has been bolted as closely as possible in a central posi-
tion, put the chalk at work on the surface B, and make the
sides of that space run as true as possible. So true, in fact, that
no variation whatever can be detected.
It is also necessary that the flange C be so mounted or caught
by the bolts that there is no danger of the flange being sprung.
To this end, look closely at C, with the eye exactly in line with the
flange, and see if there is the slightest wobble or "weave” of the
flange to be detected. It is the inner bore A which is to be turned
out, but the tool and the work must always be set by the surface
B, which is a fraction of an inch larger in diameter than the main
bore A. This enlargement of the cylinder is called the “counter-
bore” and is always found in cylinders of well-constructed en-
gines. The cylinder head seats itself in this chamber, therefore
the reboring of the cylinder does not alter the fit of the heads.

THE SCREW-CUTTING LATHE.
91
When all the shoulder has been removed between A and B then
the limit of reboring has been reached.
A little thinking will show that the cylinder can be so bolted
that one of the flanges, say at D, may be bent or sprung a trifle
by uneven tightening of the bolts. It is also evident that the
bending of one of the flanges might, and probably would, pull the
counterbore B a little out of line to one side, so that the end D
of the cylinder would be out of center and the new bore of the
cylinder would not coincide with the counterbore at D, end of the
cylinder. This is one reason why face-plate cylinder boring is
not very desirable; it necessarily being impossible to caliper the
Fig. 50–Cylinder Mounted on Slide Rest.
flange D counterbore at the same time flange C is calipered.
Therefore it is desirable to mount the cylinder for boring in
such a manner that both ends may be gotten at for calipering.
Hence the necessity for mounting the cylinder on the slide rest
as shown by Fig. 50.
In this engraving it will be seen that the cylinder is placed
upon two pieces of wood which have a circular place cut to fit
the circumference of the cylinder. The cuts are deep enough to
prevent the cylinder from rolling and at the same time to give
bearing surface enough that the strain of the bolts does not dis-
tort the cylinder. Sometimes it is advisable, for this reason, to
mount the cylinder by the flanges. In other cases even this will

92
THE SCREW-CUTTING LATHE.
a
not do and the "plaster of paris” method is employed as described
elsewhere in this chapter.
It is assumed that the cylinder will stand bolting, and the
4x4 inch blocks are cut to fit the cylinder, and also the cuts in
the lower pieces are made just deep enough so that the center of
the cylinder will coincide with the center of the lathe. Some-
times more than one trial is necessary to get the bottom blocks
cut deep enough, but a little measuring will enable them to be cut
deep enough without much trouble. It is well to cut deep enough
so that the cylinder will lie a little too low, then build up
desired height with sheet iron, paper or similar substances.
It will be noted that the bolts which hold the blocks and
the cylinder are slipped into slots in the slide rest. If these slots
are not present some other means of fastening the cylinder must
be studied out. Frequently four bolt holes drilled and tapped
into the slide rest will do the business. Centering sidewise must
be done by means of slotted holes in the blocks above mentioned,
and if the measurements are carefully made and followed there
will be little or no need of much slotting of the holes mentioned.
to the
CENTERING THE CYLINDER.
Once the blocks are in place and the bolts tightened with the
fingers procure a pair of inside calipers and proceed to adjust
the cylinder centrally with the boring bar which has already
been put in place between the lathe centers. Fig. 50 shows
in a general way the method of fastening and calipering the
cylinder, and Fig. 51 gives a more detailed idea of the proper
way to perform this important operation-perhaps the most im-
portant one of the whole, for if the cylinder is not very accu-
rately centered with the boring bar all subsequent operations will
be of little value because the entire engine will be out of line when
again assembled, unless the new bore of the cylinder is exactly
true with the counterbores at either end of the cylinder.
With the calipers as shown by Fig. 50 measure the distance
on top of the boring bar between it and the top side of the
counterbore, then, without changing in the least the distance in
the calipers, measure between the bar and the bottom of the
counterbore. The measuring should be done with the calipers
held exactly vertical, something as shown at B and in D, Fig.
51. If the measuring is done in the directions shown by the

THE SCREW-CUTTING LATHE.
93
letters in question, then any vertical adjustment which may be
made to the cylinder will not affect the lateral adjustment.
Should it be found that the calipers as adjusted at B will not fill
the space D, then the cylinder must be raised slightly by packing
under one or both of the wooden blocks by which the cylinder is
B
с
D
Fig. 51-Method of Centering Boring Bar.
fastened to the lathe. After a reasonably close adjustment is
made as above directed, proceed to caliper the spaces A and C
and equalize them in the same manner, moving the cylinder side-
wise by means of the slots in the wooden blocks, already de-
scribed.
It is always well to make a rough adjustment, say within
1-16 inch in both vertical and horizontal directions at either end
of the cylinder before attempting the finer adjustments. In
fact, this rule should always be observed. If the calipering be
done as nearly vertical and at right angles thereto as possible the
adjustment will be much more simple than if the calipering be
done at E and F, for the reason that the calipering should be al-
ways done in the line of possible adjustments, which are verti-
cally and horizontally with the cylinder-fastening arrangement,
used in this instance. Were the cylinder held at any other angle,
then the calipering should be done at that angle and perpendic-
ular thereto.
THE CALIPERING.
Calipering, in itself, is almost an art.' Upon it depends the
accuracy of almost every machine-shop operation. To do good
calipering requires long practice and the use of brains. A few

94
THE SCREW-CUTTING LATHE.
fundamental directions only can be given here regarding a mat-
ter 'which should have an entire chapter devoted to it, but the
matter is so extensive that it must be treated elsewhere. To be-
gin with, always hold the calipers lightly yet firmly, and hold
them in a vertical position. Fig. 52 shows that the calipers must
always be held straight away from the center of a shaft when
calipering anything outside of that shaft, and the same holds
good when calipering the inside of a hole. In a round hole
the calipers must pass through or toward the center every time,
and invariably they must stand at right angles to the surface
which is being measured from, and this is true no matter whether
the surface is flat or curved.
But there is another direction in which the calipers can be
wrongly held, and which will give incorrect readings to the meas-
urement. This way is shown by Fig. 52, the incorrect method
B
Fig. 52-Bad and Good Calipering.
being shown at A, the correct method at B. In this, as in Fig.
51, the points of the calipers must stand vertical (perpendicular)
to the surface to be measured from. In other words, the caliper
points must stand “straight up” from the surface which is being
calipered from or to. It is readily seen that the distance A
shown by the calipers is greater than that shown by B, hence if
one side of the cylinder is calipered to the boring bar like A, and
the other side be calipered like B, then the boring bar will not be
in the center of the cylinder, no matter how much calipering is
done.

THE SCREW-CUTTING LATHE.
95
When very thin cylinders have to be chucked, and when the
clamps might spring the walls of the cylinder out of shape, then
it is well to mount a box on the slide rest as shown by Fig. 53,
Fig. 53-Setting Cylinder with Plaster.
block the work in exact position, then pour in plaster of paris
(calcined plaster) until the work is covered. The plaster will
hold the work securely, but no adjustment can be made except by
moving the box and blocks bodily, vertically or laterally. When
very thin shells are to be bored, like pieces of tubing, the cutting
action of the tool frequently causes the sides of the tube to spring
or buckle, resulting in a very uneven bore. This tendency to
distortion is cured by the plaster backing, which holds the work
most securely. When such thin pieces are to be bored or turned
a small stream of water should be made to run over the cutting
edge of the tool continually while the tool is at work. A small
pipe leading into the hole to be bored will serve to conduct
the water to the working point. A very small stream, scarcely
larger than a needle, will prove amply sufficient for this purpose.
CHUCKING WORK WITH PLASTER.
When mixing plaster for setting a cylinder do not be afraid
of getting the mixture too thin. Thick stuff like mortar will not
answer the purpose, although a very small portion may be mixed
a

96
THE SCREW-CUTTING LATHE.
a
and pour
to that condition and used to plaster up the outlets in either end
of the box around the flanges of the cylinder. When there are
considerable spaces to be filled, and plaster is scarce, build up a
little wall with pieces of iron, nuts, bits of scrap, or any bits of
metal which come handy, using thick plaster as mortar and the
bits of metal as bricks. Indeed. pieces of brick may be used
to advantage for this purpose, their only object being to save
plaster in closing the end openings.
With every opening closed except at the top, mix the plaster
thin like cream,
pour it into the box until the cylinder is com-
pletely covered. If the plaster does not readily run into every
crack and crevice, then the mixture is too thick and will not do
a good job. Mix the plaster by pouring plaster into water, stir-
ring smartly all the time. Do not try to mix by pouring water
into a box of plaster.
When an ugly job has to be supported on the face-plate
of a lathe, plaster can frequently be used in connection with a
few bolts, the latter serving to anchor the work so that it can-
not get away; then build up under unsupported parts with plaster,
which for this purpose should be mixed thick enough to "stand
alone.” If, for any reason, there be required considerable time
for the adjustment of the work while the plaster remains soft,
then mix with vinegar instead of water, or put a lot of acetic
acid into the water used for mixing the plaster. This substance
delays the setting of the plaster and gives a chance to use it like
putty for a considerable time, whereas if mixed with water it
would have been set solidly in a fraction of the time.
TOOLS AND “JIGS.”
The lathe in itself is a most useless appliance. It can be
used only as a convenient means of applying to work a number
of tools and "jigs.” Nobody can do any work with a lathe.
That machine would stand idle forever were it not for the little
tool which gets busy with the metal placed between the lathe
centers. Take this view of the case, Mr. Blacksmith, and
don't rely upon the lathe for an increase in your business. In-
stead, just get busy and devise a lot of special tools which you
can use in the lathe in order to turn out lots of work.
Doubtless you have
have a power drill in the shop, or will have
as soon as the lathe is set up. It is too bad to do drill work in a

THE SCREW-CUTTING LATHE.
97
good lathe—too big a club to kill a little mosquito with, but drill-
ing can be done in the lathe_lots of it, and good drilling, too.
Some chucks will be required for holding the drills, and you can
buy any one of half a dozen good makes of drill chucks, or you
can make some excellent drill chucks and fit the drills to them.
No matter whether the chucks be made or bought, make
them interchange between lathe and drilling machine. It only
requires a very simple tool like that shown in Fig. 54 to do the
business. A bit of steel shaft turned to fit the taper hole in
Fig. 54-Drill Chuck.
spindle of lathe or drill, then if it be for the lathe, put it in place
in the spindle and proceed to drill the hole to fit the shanks of
the drill to be used. If there are several sizes of shanks, make
as many chucks as there are sizes. If the drill or lathe be pur-
chased from the maker, have the hole in spindle of each made
to suit your requirements, and if the holes are not alike after
the machines arrive in the shop it is often possible to make a
reamer to fit the lathe spindle taper and ream out the hole in
drill to the size of hole in lathe spinde.
When it is not convenient to do the reaming act, make two
special chucks, one for drill, the other for the lathe, and ream
each to fit the other. By so doing all the tools for either drill
or lathe are at once made interchangeable and may be used at
will in either machine.
It is necessary to provide chucks for holding large drills and
small drills also, and a very good way to do it (if store chucks
are out of the question) is to make a small chuck for the little
drills and fit the small chuck right into the big chuck
shown by Fig. 54. This settles the interchangeable matter
at once, and it is a very handy way for the reason that
when a small drill and a large one are to follow each other in
use it is not necessary to remove a taper shank chuck from the
lathe. All that is necessary to make the change is to loosen the

98
THE SCREW-CUTTING LATHE.
set-screw in chuck (Fig. 54), remove small drill chuck and put
in large drill. It is presumed that the drills and the small chucks
all have straight shanks, while the holes in drill and lathe spindles
are tapered.
The smith should use “jigs” in lathe work or in drilling,
whenever possible. A "jig" is a simple device for holding work
while a tool is acting upon it and should be so constructed that
the different pieces of work acted upon while in the jig will all
interchange with each other as far as the work done is concerned.
For instance, should it become necessary to drill holes exactly
similar in size and location in the ends of many pieces of bar iron,
say 38 x 1/4 inch for a fence, a jig should be used by all means.
It would not pay the smith to lay out all the holes with center
punch, hammer and rule and then drill each hole to the mark
thus made. That would be “making” the fence. The smith should
"manufacture" the fence, therefore he selects three or four bits
of iron, drills a few holes in them and arranges stop pins and a
clamp bolt to hold the pieces of iron under a guide hole (steel
bushed if many holes are to be drilled), which causes the holes
to all be located alike. This is a "jig.”

CHAPTER XII.
TURNING WOOD IN THE IRON WORKING LATHE.
The average machinist is not a phenomenal success as a wood
turner, and it is not to be expected that the smith has extraordi-
nary latent talent in that direction, still, by the use of a small
amount of brain matter both the machinist and the smith will be
Fig. 554"Scraping” Wood.
able to turn out almost any job which may come along. Do not
get the idea that wood can be profitably turned with ordinary
lathe tools. It is true that a piece of wood may be turned to
any desired size and shape in the lathe, exactly as a piece of iron
is turned, but it is not profitable to do so.
Wood turning requires a much higher surface velocity than
metal turning, and the average screw-cutting lathe is not speeded
fast enough to do good wood turning on very small diameters.
Even the highest speed used for filing, polishing or drilling is not
fast enough for working wood of the same diameter, therefore,
if the smith desires to add wood turning to his machine work,
a special pulley must be provided in order to give the necessary
speed. In fact, for turning wood shapes from one to two inches
in diameter the lathe spindle should run about 1,000 revolutions
to the minute.
For turning rolls five or six inches in diameter the iron-
working lathe answers very well, and the speeds can be adjusted
99

100
THE SCREW-CUTTING LATHE.
to suit. The great secret of wood turning is to cut the wood, not
to scrape it, as most machinists and patternmakers do, as the
writer is forced to testify. Nine men out of ten, in attempting to
cut a piece of wood in a lathe, will present the tool as shown by
Fig. 55, so as to take a scraping cut, when Fig. 56 shows the
Fig. 56—"Cutting" Wood.
proper way. “Don't scrape if you want to turn” is the proper
maxim for the wood turner, be he machinist, smith or any other
man.
For roughing out work, say for large rolls or any other jobs
which have considerable straight surface, the tool shown by Fig.
57 is the proper one to use. The diameter of the bend may be
Fig. 57—Slide Rest Wood-cutting Tool.
larger or smaller, according to the size of the work to be done.
Bent around a 34-inch rod gives a tool suitable for rolls of
4 inches to 8 inches in diameter, and by bending around a 2-inch
form a tool will be secured which gives satisfaction on work up to
24 inches to 36 inches in diameter. In bending the tool, also in its

THE SCREW-CUTTING LATHE.
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с
A
8
forging, great care should be taken that the outside of the bend
is at right angles (square) with the top and bottom edges of the
tool. It is not the inside of the bent portion which should be
made thus square, but the outside portion.
Fig. 58 shows the method of grinding this form of tool. The
face, B C, comes next to the work and is made square with the
length of tool as above, and the cutting is done at C. When
grinding is necessary it is done at C, until the face B C is gradu-
ally worn away to the line A B. This is about as far as
grinding can be carried, and a new tool should be made
when the wear approaches this line. The inside of the tool
is never ground. It is filed up when the tool is made, be-
fore it is hardened and finished with an Arkansas slip. The
smith should have several of these very useful stones. They
come in all sorts of shapes and sizes and may be obtained
from any dealer in hardware and tools. A couple of round Fig: 58
-Grind.
slips will be necessary for whetting the tool shown by Fig. ing
57 ; one stone 34 inch in diameter and another 1 inch Tool.
through will answer. If a 12-inch stone be also added the variety
will be as great as will likely be called for. The smith can also find
use for a three-cornered stone, one with a knife edge and two or
three flat stones of different widths and thicknesses. They are
very handy things to have and cost but a trifle.
When the tool shown by Fig. 57 is used for turning rolls it
should be set square against the wood and made to take a cut
in either direction. That is, do not run the carriage back by
hand, but reverse the feed and make the tool cut on the return
trip also.
Wood
INSIDE AND OUTSIDE TURNING TOOLS FOR SLIDE REST WOOD
TURNING.
The tool shown by Fig. 57 is an all-around tool which may
be used for almost any straight outside work. As for inside
work in wood, there is very little of it which the smith will ever
be called upon to do. Perhaps the making of rolls for moving
houses will call for a hole through the center of each roll in order
that the seasoning of the wood may not crack the outer surface
full of season checks. A small hole through the center or axis
of the roll will prevent prevent this, and the hole must be made
when the rol! is turned.

102
THE SCREW-CUTTING LATHE.
For the purpose noted above nothing is better than the
old-fashioned “pod auger," as shown by Fig. 59. This tool is
easily made by the smith, and the size may vary from 1 inch in
B
TOP VIEW
SIDE VIEW
SECTION ON AB
Fig. 59-The "Pod Auger."
diameter to even 6 inches if pump logs have to be bored. This
tool is easily made by welding a bit of steel to the edge of a piece
of flat iron, and then plating out and forming up as shown by the
engraving, after which the tool is welded to a round shank of
sufficient length to reach through the longest piece to be bored,
and with additional working length to permit of its being held
in a chuck.
There are two methods of using tools of this kind: one way
is to catch the shank in a chuck placed in the tail -spindle, and
mount the roll on the face plate or in another chuck. When this
is done the free end of the roll is usually held by means of a
hollow center, the diameter of which is the same as that of the
pod auger. The hollow center is placed in the tool post and the
slide rest brought up and held by means of the lead screw. The
hollow center furnishes a support and guide for the auger.
The other way is to mount the roll in V notches (blocks
of wood placed across the ways of the lathe) and put the auger
shank in the spindle chuck. In this case the roll is fed against
the auger by means of the tail spindle and a block of wood should
be placed between to prevent damage between auger and tail
spindle.
TURNING UP PATTERNS.
A considerable amount of pattern work must necessarily be
done by the smith if he expects to do any machine work. Fre-

THE SCREW-CUTTING LATHE.
103
quently a good deal of machine work can be avoided by a skilful
arrangement of the pattern, and many patterns must be turned
up in the lathe, and tools and the “know-how” are necessary for
this kind of work as well as for lathe work.
Probably the smith is well acquainted with the "dog" used
by wood turners for holding work in the lathe. Fig. 60 represents
the most common variety, which is made by turning up a shank to
fit the lathe center, drawing the end to a wide V shape, and then
filing at A and A so as to leave a central point and two wedges,
Fig. 60-Wing Dog.
one on either side of the point. This is used as a live center
and is driven into the wood sufficiently to rotate it.
An ordinary center is used and the rig is all right for hard
wood, but is very apt to drag out
of place in soft wood, provided
much heavy work is to be done.
A much better center for soft
wood can be very easily made
by the smith. Fig. 61 shows Fig. 61-Making a Star Dog.
how the blank is turned up, and Fig. 62 illustrates how the teeth
are cut with a file and a hack saw. Any number of teeth can
be made as desired, so that the dog may be given as much holding
over as may be found necessary.
It will be noted that the conical center is left
much longer than the teeth. This is for the pur-
pose of letting the work be placed between centers
while the lathe is running. When a large number
Fig. 62—Star
of pieces have to be made, the time lost in stopping
to put a new piece of wood in the lathe is consider-
able, and the long center permits of the work being placed between
the centers and then the tail stock may be run forward, thus
holding the work securely.
The tail center to accompany this form of dog is made in the
Dog, Complete.

104
THE SCREW-CUTTING LATHE.
А
same manner, only the ring at the end is turned thin, as shown in
section by Fig. 63, and is left whole, in a continuous ring, instead
of being cut into teeth as was the case with the soft wood dog,
Fig. 61. An improvement of considerable worth may be made in
centers of this kind by drilling the oil hole shown at A. Fig. 64,
whereby the inside of the cup ring may be
lubricated. The hollow center noted
above as fitted to the tool post for use in
turning and boring rolls is made in the
same way as shown by Fig. 63, except
Fig. 63—Cup Center.
the center is missing and a hole is bored
through that point large enough to receive the pod auger described
elsewhere.
Usually, pattern work requires a considerable quantity of
face-plate work, and small face-plates should be duplicated, several
being furnished, or made as noted in a previous chapter. One
small face-plate should have a screw, projecting from 1/2 inch to
1 inch, in the middle of the plate, as shown by Fig. 64. In
using, the bit of wood is simply screwed hard against the face-
plate, where it is held by the screw sufficiently
secure for turning purposes.
This method of fastening answers very
well for small objects from 1 to 2 inches thick
and less than 6 inches in diameter. For larger
work another chuck or face-plate should be
provided, similar to that shown by Fig. 64,
but with the exception that the screw is
omitted and four holes drilled through the
edge of the plate as shown by the engraving
in question. Indeed, the holes may be put in Fig. 64—Screw Chuck, .
the screw-plate and for large work the power of the central screw
is reinforced by as many common wood screws, put through the
holes, as may be found necessary to hold the work in place.
Suppose, for instance, that the smith desires to make a
pattern for a simple set collar to go on a I 15-16-inch shaft.
This object is merely a ring of cast iron bored to fit the shaft
and fitted with a set-screw to hold it in place. Fig. 65 shows one
.
of the face-plates with a bit of soft wood fastened in place by
two wood screws driven in from the back through the holes
mentioned in the preceding paragraph. In this illustration a tool

THE SCREW-CUTTING LATHE.
105
rest fixed in the tool post is represented at A, the block screwed
to the face-plate F. and two tools, B and C, are shown, one in

B
Fig. 65-- Making a Collar Pattern.
position for inside cutting, the other for outside work. In practice
the tool would be used at C first, in order to remove the rough
corners, thereby permitting the work to run smoother than
possible with the corners on. After the corners have been
taken off a light cut should be taken to make sure that the work
is exactly true, then the tool may be shifted to position B and the
inside of the pattern worked out.
It will be noted that both the tools shown by Fig. 65 are in
position to take a scraping cut, notwithstanding the remarks
made in another paragraph against this very method of cutting.
However, it is necessary to take scraping cuts in a good deal of
pattern work and in working to exact dimensions. While scrap-
ing is permissible in this kind of work, to a certain extent, it
should never be practiced or tolerated in straight turning.
The tool shown by Fig. 65, and in detail by Fig. 66, is a very
handy one for either the wood turner or the machinist. The

А
8
Fig. 66—Two Handy Hand Tools.
tool is easily made from a bit of square tool steel 3/8 inch or
One end of the steel is drawn to form a
1/2 inch square.

106
THE SCREW-CUTTING LATHE.
shank and is fitted with a more or less elaborate handle-
usually less—and the other end needs nothing except grinding,
as shown by the sketches. A is a side view of the grinding while
B shows a side view of the tool looking over the top. If the
smith does not catch the idea from that sketch, then turn the tool
so one corner will come exactly upward, and in that position apply
the tool to stone or wheel and grind a nice, clean bevel as shown.
This tool works equally well on wood or metal and is a very handy
addition to the kit of either smith or machinist. For metal work-
ing the tool should be hardened a little more than for cutting
wood, but once fixed for iron or steel working the tool may be
used for wood without changing the temper.
LABOR-SAVING JIGS AND ATTACHMENTS.
Turning taper work is one of the things which often has to
be done and which requires a good deal of ingenuity on the part
of the operator. If a piece 2 inches long on a 20-inch shaft has
to be turned to a taper of 12 inch to the foot, then the smith-
machinist is in for quite a bit of figuring. The best the smith
can do is to “set over” the tail stock enough to bring the desired
taper. One-half inch to the foot taper means 0.835 inch in 20
inches, therefore the tail stock must be set over that amount and
the work put between centers and the turning done in the same
manner as if the shaft were perfectly straight instead of tapered.
It is quite easy to arrange a taper attachment to the lathe
in such a manner that not only that taper turning be readily done,
but that taper boring may be just as easily done. The way re-
ferred to is to mount a straight steel bar on the back side of the
lathe, and arrange bearing so that the bar may be adjusted and
fastened at any required angle with the lathe bed. Next
arrange a slide to fit the bar, with an adjustable gib to make
a close fit, then attach the slide to the back end of the
slide rest and remove the cross-feed screw from the slide rest,
which will then be entirely controlled by the bar and slide on
the back of the lathe and as the carriage moves toward and away
from the head stock the tool moves to or from the center of the
work. This arrangement, which is attached to some lathes, will
enable taper pins to be made accurately, and it can also be used
for boring taper holes which the pins made will surely fit.
With the bare lathe, if the smith has need to bore a taper

THE SCREW-CUTTING LATHE.
107
hole, he surely is "up against it.” About the only thing he can do
is to count the number of turns the cross-feed screw must make to
move the tool through half the amount of taper. Then, with a
similar counting or calculating of the number of turns or revolu-
tions the spindle will make while the tool travels along the dis-
tance to be tapered, the smith is able to find out just how far to
turn the cross-feed handwheel during each revolution of the
lathe spindle. For instance, it is desired to turn a taper of
1/2 inch to the foot in a hole 3 inches deep. The bore means
that in 3 inches the taper will be one-fourth of 1/2 inch, or 1/8
inch. As half the taper is on either side of the hole, one side
should have a taper of 1-16 inch in 3 inches. Allowing that the
feed of this particular lathe is 64 to the inch, then the cross-feed
screw being 12 threads to the inch, it is evident that the cross-feed
handwheel must be turned 12-16 of one turn, or 34 of a revolution
while the lathe spindle is making 3 x 64 turns. In other words, the
handwheel must be turned one-fourth a turn to each inch of
hole to be bored. The task now becomes an easy one. The
smith-machinist can easily divide up the stated circumference
into 64 imaginary parts and then turn the wheel one of those
parts at every revolution of the lathe spindle. In taking the
roughing cuts it will be necessary to feed only once in three or
four revolutions of the spindle, advancing the feed, of course,
three or four spaces each time, instead of a single space as when
feeding each time the spindle revolves. In this way the lathe
can be made to turn or bore a mighty slick taper without any
taper attachment, or without sending the apprentice for a can
of “taper oil,” or without “throwing the tail end of the lathe
around” with a crowbar.
a
OTHER TOOLS TO BE ADDED WITH PROFIT.
There are a great many appliances, jigs and fixtures which
may be added to or used in the lathe with considerable profit to
the owner of that machine. The smith can rig up jigs whereby
he can do milling in the lathe, he can add a planing attachment
and he can also make the lathe do gear cutting, polishing and
a dozen other things. Indeed, an "amateur" of the writer's
acquaintance had a fine lathe to which he had added by purchase
or by his own make over twenty attachments for performing as
many entirely different operations. The smith will find that it
.

108
THE SCREW-CUTTING LATHE.
a
does not pay to carry this business too far. Remember that all
the money earned for him by a ląthe is by the work turned out,
and if too much time be spent in changing attachments or in
“ "rigging up" much less will be earned than if the lathe be kept
at work all the time.
The smith can easily arrange the lathe so that it will cut up
round iron in mighty good shape. It costs very little to so rig
a hollow spindle lathe, and the manner in which the pieces drop
off is good to see. Still, however good to look at, the arrange-
ment does not pay. The smith has $200 at least invested in that
lathe and he can keep it busy all day, charging 60 cents each hour
at least for the lathe and a man to run it. It therefore costs
60 cents an hour to cut off iron, besides the interest on the invest-
ment and some other things. The lathe is also tied up and is
kept from its proper work.
How much better, then, it is to put in a little power hacksaw,
which costs about $75, and which may be started by a boy, and
which requires no attendance at all while running, and which
stops as soon as the piece of metal is cut off. Just figure how
far that 60 cents an hour would spread itself out on the cost
of running the power hacksaw. In addition to the decrease in
cost of cutting off, the lathe is all the time earning its profit
otherwise, instead of being tied up to the work of a $75 machine.
The same is true in other directions. Do not load up the
lathe with "attachments” for doing this and that. Rig up special
machines. Cast iron is cheap and it costs little more to rig up a
stand and a shaft and bearings than it does to accommodate some
special machine or arrangement to the lathe.
It is the special machine which pays the most, and the more
special machines the smith can make and keep at work all the
time, the more money he is making. Write it down, when making
a special machine, that the cost of that machine ceases when it is
completed, and that its output is clear gain, and that you will not
have to deduct therefrom the time spent in adjusting "attach-
ments” to the lathe, neither will you have to make any allowance
for time spent while you were rigging it up and using it as a
special machine.
The smith should have a vertical drill in the shop, and he is
entitled to that tool even before he arrives at the dignity of a
lathe. The next tool purchased should be the power hacksaw,

THE SCREW-CUTTING LATHE.
109
then a shaper, next a milling machine, with all the special
machines sandwiched in between. By the time the above-men-
tioned tools have been added the shop will have become too
important to be called a "smith machine shop," and the machine
part must be made a department by itself.

CHAPTER XIII.
MAKING A “QUARTER-TURN" CRANK SHAFT.
By a "quarter-turn” crank shaft is meant one which has
two wrist-pins at right angles to each other, or 90 degrees apart.
Fig. 67 represents a crank of this character and it is about as it
is proposed to make the shaft to be described below. The di-
mensions of the shaft will not be given, that data being supplied
by the smith-machinist in accordance with the particular de-
mands of the case in hand.
Do not attempt to make a crank shaft, or any other piece of
machinery, without first making a drawing or at least a sketch
of it, showing the work as it is to be when finished. It is very
B
Fig. 67-Quarter-turn Crank Shaft.
easy to get into the "sketch habit,” and it is of great value to
any mechanic. It saves a lot of trouble from misunderstanding,
and totally obviates the necessity for any “cut and try” work
whatever.
Referring to Fig. 67, it will be noted that the two cranks,
A and B, stand at right angles to each other or, in draughts-
man's language, they are 90 degrees apart. It will also be seen
that there are three separate and distinct centers in the crank.
One, the main center, and two others, one for each crank. These
centers must be most accurately laid out and drilled, for upon
their accuracy depends the truth of the entire piece of machinery.
There is a center in each end of wrist A, and two other
centers in wrist or crank B. If either one of these centers
departs even so slightly from its accurate location, then there will
110

THE SCREW-CUTTING LATHE.
III
be one or more defective wrist pins which can never be able to
run true or cool.
GOOD AND BAD FORGINGS.
The first thing, after the drawing of the crank shaft is made,
is to obtain the forging or "blank.” Fig. 68 shows a well-forged
A
8
Fig. 68-Blank Forging for Quarter-turn Crank.
blank with the crank blocks turned at approximately 90 degrees
with each other. And it is wonderful how closely a good ma-
chine blacksmith will come to getting things exactly right. It
used to be a standing joke in the shop where the writer learned
the machinist's trade that when a man did a bad job the fore-
man would gravely remind the man that he must do better if
he stayed in that shop, for “the blacksmith downstairs can forge
closer than you can turn with a lathe.” And there was a good
deal of truth in it, too.
Anyone who has had a great deal to do with automobiles has
noticed the frequency with which the crank shafts break. A
flood of light was turned on that matter the other day when the
writer happened to be in a large shop where they were turning
out automobile cranks by the hundred on contract. These blanks
did not look the least like the one shown by Fig. 68; instead of
that the blanks presented the appearance indicated by Fig. 69,
A
A
Fig. 69—Cheap but Bad Engineering.
both cranks being forged on the same side—a much easier oper-
ation—and then the shaft was twisted as indicated by the dotted

II2
THE SCREW-CUTTING LATHE.
lines, to bring the cranks to a quarter turn. It certainly cannot
make a crank any stronger to twist the shaft between the wrist-
pins, and the writer is of the opinion that many more of the
twisted cranks break than of the forged angle crank shafts.
CRANK SHAFT JIGS.
Having secured a forging, made to suit, the next thing is to
lay it out and put it in the lathe and begin to finish the article.
It is best to make a couple of jigs for use in making these
shafts, and the jigs in question will more than pay their cost in
the one job which we are going to take in hand. Fig. 70 shows
one of these jigs, but they may be made in many different forms,
B
K
G
Fig. 70-Jig for Turning Crank Shaft.
the only requirements being that it is possible to clamp the jigs
firmly upon the ends of the crankshaft in such a manner
that the jigs will not slip or yield in any manner during the en-
tire machining of the crank shafts.
This jig consists of a square cast iron block, A, with a
carefully bored hole at H to fit the end of crank shaft C. After
the jig is otherwise finished a slot is cut at G with a hack saw,
so that by tightening the nut B the jig may be clamped firmly
upon the crank shaft—so tightly, in fact, that the jig will not slip
or move during all the turning and filing operations upon the
shaft.

THE SCREW-CUTTING LATHE.
113
It is necessary that at least two sides of jig may be made
square with each other, and also with the face on front side of the
jig. It may save a little labor if the sides, K and J, be squared
up after the hole H and the centers E and F are made. To pro-
ceed in this way chuck the jig block, which may be of plain cast
or wrought iron or steel, and bore the hole H. Then mark the
circle D very accurately with a pointed tool held fast in the tool-
post, make the distance of circle D from center of H exactly to
the throw (length) of the crank. Take great care in making
this circle, for upon its accuracy depends the accuracy of the
crank shaft. Two of these jigs must be made, one for either end
of the crank shaft, and it will be well to omit circle D until both
jigs have been finished; then put one of the jigs, or both of them
upon opposite ends of a short shaft of the exact diameter of the
proposed crank shaft, and clamp the jigs tight. If a short shaft
is not to be had, use the crank shaft, turning up each end enough
to receive the jigs.
USE A SURFACE PLATE.
In clamping the jigs to the shaft they should be laid upon a
surface plate. Anything will answer that is smooth, true and
hard. Surface plates may be purchased from any dealer in ma-
chinists' tools. A plate 12 inches by 18 inches will do nicely for
the machinist, and will prove a paying investment. In fact, a
surface plate and a surface gage (see Fig. 72) are absolute
necessities for doing good machine work. Any smooth, true
surface of planed or turned cast iron will answer for a surface
plate, and for a substitute the large face-plate may be used, but
it is not nearly as satisfactory as a regular surface plate.
Referring again to Fig. 70, it will be noticed that vertical
and horizontal lines pass through the center of hole H, and
through centers F and E respectively. These lines must be ac-
curately made, and there are at least two ways of making them.
Either the lines may be made before the hole H is made, and the
hole H accurately drilled where the two lines cross, or hole
H
may be drilled, the jigs placed on the shaft which is squared
up as shown at G, Fig. 71, and the lines drawn by means of try
square and surface gage.
The front end of each jig must be machined or filed smooth,
after which the circle D and the vertical and horizontal lines

114
THE SCREW-CUTTING LATHE.
may be drawn as follows: Dissolve some sulphate of copper
(blue vitriol) in a little water and rub some of the solution over
the bright surface of the jig ends. Allow to dry, and a film
of copper will be found deposited on the iron. The film of cop-
per shows a scratch mark very plainly and lines are easily drawn
upon the surface thus provided. The surface gage H, Fig. 71,
should be used for drawing the horizontal line at E, Fig. 70,
through the center of each jig, and the vertical line F may be
drawn by means of the try square, G, Fig. 71.
LAYING OUT A SHAFT.
Fig. 71 shows how the shaft, with jigs in place, is laid on
the surface plate, and the jigs made to bear evenly and fairly
upon the plate, also to stand square with the plate, as at G.
tot B.
A
Fig. 71-Laying Out a Crank Shaft.
The curved point in the scriber in the surface gage H is used for
testing to see that the lower edge of crank shaft is equally distant
from the plate at all points, the gage being set to one end of
shaft, then moved to the other end. When everything is all right
and the crank, C, lies exactly parallel with the surface plate, then
the line through E of Fig. 70 may be drawn in the copper
film
on each of the jigs, and where this line intersects with circle D,
there is the place for one of the centers to be made. The other
center, F, may be determined in the same way, but with try
square G, Fig. 71, instead of the surface gage illustrated by Fig.
72, which will be described later on. The smith should supply
himself with two surface gages, one small, the other, a large one,
but get the small one first.
Fig. 71 also shows how the lengths of the various parts of
the crank shaft are laid off. These points for the lathe worker
to work to the shaft blank, using the copper solution on bright

THE SCREW-CUTTING LATHE.
115
metal or common white chalk on rough surfaces. In turning,
the lathe worker has only to cut up to these marks and then stop.
SURFACE GAGE.
The surface gage, shown in Fig. 72, is a necessary tool
when work is to be laid out. It can be purchased ready made,
but would advise the repair man to make it. He is obtaining a
good tool and learning something of greater value than the tool.
If there be no time for tool making, then buy, by all means, but
it is only in extreme cases that a man cannot find time to make
himself a good surface gage.
To make the surface gage
shown in Fig. 72 obtain a piece of metal something like cast
iron, about 272 or 3 inches in diameter. Then turn up to any
fancy shape desired. Drill for the rod C, which is about 3-16
inch in diameter and made of steel; tap in thumb screw B to hold
C in place. The block, D, is made in two pieces, one of which
slides upon C, and is clamped to it by the thumbscrew. The
scriber, G, is of 18-inch steel with end, H, curved. The thumb-
screw, F, clamps G into the block, and clamps the two blocks to-
8
LIQUID
Fig. 72-Surface Gage.
gether. The scriber may be turned in any direction vertically,
and by sliding block D it may be placed at any required height
above the surface plate.
By setting point G to line E of Fig. 70 and then sliding the
gage to the other jig it will be shown at once whether or not

116
THE SCREW-CUTTING LATHE.
the lines È on both jigs are the same distance from the surface
plate. If not, the lines must be mended.
DRILLING CRANK CENTERS.
Having found that the center marks on both jigs prove true
by means of tests with surface gage and try square, the four
crank centers (two on each jig) should be drilled and counter-
sunk. This is a job which calls for the highest skill of a good
machinist. Fig. 73 shows how to do it. Around the quartered
ch centers small circles are drawn to the exact diameter
which it is desired to countersink the center. These circles are
B
G
ga
--
A
Fig. 73-Drilling and Countersinking Crank Centers in Jigs.
shown at A and A, and they are further marked by four or more
center punch marks equidistant from each other, as shown
in Fig. 73. The object of these punch marks is to enable the me-
chanic to determine when the countersinking is going right,
and to make sure that the tool is not cutting to one side, instead
of straight ahead
A small drill is started at D and is run in as far as necessary,
clearing the lathe centers as described in Chapter IV. When
ready to countersink the small drill hole there is no guarantee
that the countersink will cut the same on each side of the center.
Indeed it almost always runs to one side, as at A, Fig. 74.
Either the metal is softer on side of hole A, or some pressure

THE SCREW-CUTTING LATHE.
117
causes the drill to cut that side farthest. At any rate, the hole
goes toward a, and our business is to correct it. All changes
must be made before the straight portion of drill on countersink
gets to work. In countersinking, this must be done anyway, as
only the point of the tool touches the work.
With the hole started nearest a, Fig. 74, it is necessary in
order to make a decided change in the direction of the hole, to cut
a channel, as shown by e at B, using a small cold chisel for that
purpose. If the proper amount be chipped out, the hole will
straighten up when drilled a little more, taking the position shown
at C. In this condition the countersink is correct and should be
continued until its edge just touches the limit circle all around, as
shown at D, when countersink may be stopped with every assur-
ance that the centers are finished as accurately as is necessary.
ROUGHING OUT AND FINISHING.
With the jigs once properly drilled and countersunk, give
them a final surface gage test to see that they are perfectly
square with each other and with the shaft and proceed to rough
out the crank shaft. It is well to cut out some of the metal be-
tween the arms of each crank before the shaft is put in the lathe.
If in a regular machine shop, the cranks would be clamped
together and the chunk of metal cut out on a shaper. As there is
no shaper at hand, drill a row of small holes 14 or 38 inch around
the piece to be cut out, and finish the job with a hack saw. If the
e
b
d
8
D
Fig. 74-Accurate Drilling or Countersinking.
smith has arrived at the understanding of the proper value of
milling cutters, then he will clap a cutter on an arbor, clamp the
crank shaft to the slide-rest, and mill out the square bit of metal
in a hurry.
Do not take a finishing cut over any portion of the crank
shaft until all has been roughed out and worked down close to
size. It is extremely probable that more or less straightening

118
THE SCREW-CUTTING LATHE.
will have to be done to the shaft, as the turning proceeds, for it
is usually found to be the case that a piece of metal changes shape
when the outer portion or skin is removed. Therefore, rough out
the shaft, turn down nearly to the finishing cut, then test again
upon the surface-plate and apply the necessary corrective straight-
ening that may be necessary.
To turn the wrist-pin of any crank, simply put the lathe cen-
ters into the centers in the jigs which correspond to that particular
crank, then go ahead and turn up the surface concentric with the
center, after which another pair of centers is brought into use, etc.
STEADY PIECES.
Referring again to Fig. 71, two pieces of metal should be
squared up and fitted accurately between the arms of each crank
at J and K. These pieces take the strain off the wrists during
the several turning operations.
These “steady pieces” of metal should never be driven tightly
into the cranks. If they be thus driven, a strain will be set up
which will surely cause the cranks to be crooked when the steady
pieces are removed. Contrawise, if the pieces are fitted too
loosely, the crank will pinch them when in the lathe; then the
reverse spring of the shaft when it is removed from the strain of
the lathe will cause the shaft to be crooked in the opposite direc-
tion from what it was when the steady pieces were too tightly
placed. Thus, these pieces should be very accurately fitted. They
should be made preferably in two pieces and fitted to slide easily
between the cheeks or arms of the cranks. Then a piece of paper
should be placed between the two pieces of metal, thus giving it
extra thickness just sufficient to counteract the pressure of the
lathe centers and of the tool.
Having at last gotten the crank into the lathe, the rest is
easy. Anybody can do the trick now, and as one man said to the
writer when he was putting a complicated shape into the lathe :
“When you get that thing ready, I'll come in and run it for you.”
It is well to use the water cut in finishing the wrist-pins, as it is
hard to make a good job at filing them for the good reason that
they cannot be run fast enough for a good filing speed because of
being badly out of balance. Of course, they can be temporarily
balanced, but filing is a make-shift method of finishing at best,
and it is a great deal better to use the water finish and secure a
first-class job to begin with.

CHAPTER XIV.
MILLING IN THE LATHE.
In regard to a milling attachment for the lathe: while such
a fixture is a great convenience, the smith should look the matter
over very thoroughly indeed before spending any money or time
on such an attachment. The gist of the whole matter is just
this: If you ever intend to enlarge the earning capacity of your
shop, then do not make a milling attachment for the lathe. If
you are satisfied to do just what work can be handled by one
man, then the milling and any other attachments and jigs are in
order, for they are great conveniences but are not money makers.
This
may be a surprising statement to many a smith, but look
again and see if it is not the truth.
The writer has a friend who is a crank on the subject of
lathes and attachments thereto. He has a very fine lathe and
over thirty attachments for milling, drilling, shaping, planing,
gear cutting and about every other operation known to the ma-
chinist. And what is the result? The earning capacity of that
lathe is only about one-half that of an ordinary screw-cutting
lathe. Why? Because the machine is idle so much of the time
.
while attachments are being applied, adjusted and removed.
The only things in common to all operations in that lathe
are the bed, the spindle, the head-stocks and the slide-rest—and
sometimes, to a limited extent, the feed. And in addition, and
most important of all—if there is one—the cross-feed on the slide-
rest of the lathe. Even with the above mentioned very few com-
mon properties there are lots of times when it is found that the
form of bed or centers, or bed or spindles, are most illy adapted
for the work to be done and to overcome this difficulty attach-
ments have to be designcd which cost almost as much, if not quite,
as would a special machine to do the work of that attachment.
Right here is the keynote of success in machine work,
blacksmithing or any other mechanical operation. It is this:
Do not mix your machines. Put in one machine for outside
turning, another for inside work and rig up an entirely different
119

I 20
THE SCREW-CUTTING LATHE.
machine for milling and another for each kind of special work
which comes along. Let the lathe be earning money for
you
in
its own way. Do not cut down its profit-producing capacity by
stopping it half the time to turn it into a very poor substitute for
some other machine.
But, says the one-horse man: “The lathe is there, it is
idle now, so why not use it for milling and save the expense of
another machine?" It can be done, and the writer will tell how
to do it. But while rigging up that lathe for milling and spend-
ing time and money on it just remember that you are retarding
the expansion of your business and putting into the hands of
your competitor the chance to get ahead of you. “What should
be done?” Make an attachment which will stand on its own
legs instead of on those of the lathe, that's what should be done-
and the writer proposes to tell how to do that also, in order that
the man who wants to make the most money may be prepared to
do so. A special machine for fluting taps and reamers will cost
hardly more than an attachment for doing that work in the lathe
-and then you have the labor and profit from two machines
instead of from one. “Savez?”
APPARATUS NECESSARY.
a
In order to do small jobs of milling in the lathe the follow-
ing things are necessary: an arbor or other support for the mil-
ling cutter; means for revolving the cutter strongly and at
any desired speed; means for holding the work, preferably be-
tween centers; means for revolving and locking the work at any
desired part of a revolution, in order to provide as many flutes as
are required; a vise or clamp arrangement in place of the revolv-
ing centers when the character of the work requires it; a table
for supporting the centers or vise or clamps; means for moving
or feeding the table evenly, accurately and strongly in any
direc-
tion, forward or back, laterally or up and down—such feeding
to be automatic and variable in speed.
Let's now look the lathe over and see what is present and
what is lacking from the list of “means.” The milling cutter
should always be purchased ready made. It does not pay to
make them at home. While one can be made at home for $1.20,
another "just like it, only better,” can be purchased for 30 cents.
The support for the cutter—the mandrel or arbor—can be made
-

THE SCREW-CUTTING LATHE.
I21
at home and must fit the lathe. Details for this will be given
later. To support and rotate the cutter of course the spindles
of the lathe will be used. So far all is well, but now trouble
commences. It is evident that the slide-rest must be made use
of to support the work and carry either the centers or the vise
or clamp used for holding the work. The fact that there is only
a space of a few inches between slide-rest and lathe centers is
a most discouraging fact, but it can't be altered or obviated. That
is one of the "must" things and we “must” make the best of it.
Thus the range of work which can be milled in the lathe is at
once limited to one-half the swing of the lathe, less half the diam-
eter of the milling cutter, less the thickness of the sliding table
and the center raising device. Thus only very small work can be
milled in the lathe.
The length of milling cut is also very limited, and in a 20-
inch lathe it is hard to provide for milling a cut over 10 inches
long, while the diameter of the possible work, as limited above,
can hardly exceed 3 inches, however economically the device may
be arranged as regards vertical space.
DIVIDING HEAD.
In order to properly space the milling cuts around the per-
iphery of a tap or a reamer the milling attachment must be fitted
either with an index plate or a dividing head. The former takes
up a lot of room but could be placed at the back of the lathe
and could be made fairly accurate in the shop. The dividing
head usually consists of a worm wheel and screw which is
actuated by means of change gears in such a manner that any
de-
sired part of a revolution may be given to the work by merely
turning a crank a certain number of times for each cut. Both
the index-plate and the dividing head are to be attached to the
live spindle which supports one end of the piece to be milled.
A rudimentary dividing head is quite within the make of
the smith, but the index-plate is much quicker made, though not
as convenient as the dividing head, which can be made with con-
siderable accuracy provided the worm wheel is accurately spaced.
It is understood that the centers and the vise or clamp for hold-
ing work are never used at the same time, and that the dividing
head or plate is used only with the centers, or with the work
chucked on the spindle of the head or plate, therefore it is nec-

122
THE SCREW-CUTTING LATHE.
essary that the table of the attachment be made to receive either
of the above-described articles. This table must also be made to be
raised or lowered at will, in order to obtain the required depth of
cut from the milling cutter which hangs between the lathe cen-
ters above the table.
It is in the means for raising and lowering and locking this
table that the lathe milling rig becomes a complicated and cum-
bersome affair. In order to obtain any range of movement worth
considering the means for vertical adjustment must be removed
from the space between the lathe spindle and the V-ways. This
means that the raising and lowering mechanism must be placed
outside the bed of the lathe and made in two parts, one at the
front, the other part at the back of the lathe. Each part of the
attachment could be raised or lowered either simultaneously
or separately, and by connecting the two by means of a flat
plate work of almost any description could be readily held upon
the plate mentioned or clamped in the vise fastened to the plate
in question.
While it is quite possible to arrange a little milling attach-
ment to be fastened to the slide-rest which will handle taps and
dies, it seems folly while an attachment is being made for milling
in the lathe not to give said attachment as much range for work
as possible. To this end do not use the slide-rest at all, but
make a special casting to slide upon the lathe Vs, and upon this
casting place all the adjusting mechanism necessary. Then, in
order to change the lathe to a milling machine, it will only be nec-
essary to raise the tail-stock of the lathe by means of the chain
differential blocks, which should be suspended permanently above
any lathe, run the slide-rest down toward the tail end of the
lathe, past the tail-stock, which is then replaced on the Vs. Next,
swing the milling attachment into place between head and tail-
stocks and the lathe is a milling machine.
MILLING SLIDE REST.
Fig. 75 gives an idea of this arrangement, at least it at-
tempts to show what the special castings look like and how the
several adjustments are made. The main casting A (similar
figures or letters indicate the same pieces in all the views of a
figure) is planned to fit the lathe ways the same as a slide-rest.
In fact, it is one, and is gibbed down and attached to the

THE SCREW-CUTTING LATHE.
123
Or
10160318
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B
A
Side View.
E
с
B
End View.
Fig. 75-Milling Attachment for the Lathe

124
THE SCREW-CUTTING LATHE.
feed rod or screw
screw precisely the same as the slide-rest.
The casting B is the main table of the milling rig and is gibbed
to casting A and fitted with a feed screw which should be
attached to power as a cross feed, which may be worked by hand
if necessary.
The forcing of the tool into the cut in horizontal milling is
done by this screw. The table B may best be slotted for bolt
heads as shown, and to it are fastened two strong knees, C C,
which each in turn carry gibbed stocks which are fitted with
spindles for the reception of center work. It will readily be
seen that the sliding, gibbed blocks D D are raised or lowered
by screws, which in turn are geared together so as to be operated
by a single crank F. The blocks C C and D D may be moved at
will along the table B and made fast at any desired distance apart
within the limit of the table length.
Referring to the side elevation, it will be seen that the knees
C C permit the work-holding spindles to be set either above the
table B or at one side of it as shown in the side view, thus per-
mitting a great range of work and obviating to a considerable
extent the handicap of the small distance between the lathe Vs
and the lathe center. By means of the overhang thus secured
the entire distance from lathe bed to center is available, and in
many instances larger work can be handled, for the reason that
it can project down into the cavity in the lathe bed.
The details of this attachment are not shown, for the reason
that it would be necessary to work them out differently for each
type of lathe, and it is a fine piece of educational business for the
smith to work out these things for himself.
ANCIENT INDEX PLATE.
Fig. 76 represents quite crudely the time-honored index
plate, which is a disc of any convenient diameter attached to the
live spindle of the milling attachment. Holes dividing the circle
into as many—or into multiples of as many—cuts as are desired
are drilled in circles through the plate, and a pointer is rigged to
drop into one of these holes at a time and hold the plate rigid
while a cut is being made. Sometimes the plate is stationary
and the pointer is attached to an elongation of the spindle, which
passes, in this case, through the plate. When a different spacing
is required the pointer is shifted to another circle of holes which

THE SCREW-CUTTING LATHE.
125
contains the number of holes either straight or in multiple of the
number of cuts required around the circumference of the work.
MODERN DIVIDING HEAD.
Fig. 77 shows the principle of the more modern dividing
head. To the end of the spindle is attached a worm wheel with
Fig. 76—Index Plate.
a convenient number of teeth. To the block carrying the worm
which engages this gear is attached a graduated circle around
which sweeps a pointer attached to the worm shaft. Almost
any number of divisions can be given to the circumference of a
20
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Fig. 77—Dividing Head.
piece of work by turning the worm shaft a given number of revo-
lutions and parts of a revolution, as indicated by the graduated
circle noted above.
In some more elaborate dividing heads there are change
gears to drive the worm shaft, so that almost any combination of
partial revolutions can be made by complete turns of the crank,
without having to use the graduated circle at all. Means must be

126
THE SCREW-CUTTING LATHE.
provided for clamping the spindle after setting, similar to that
shown at H, before each cut is made, as the pointer in the index
plate or the friction of the worm in the gear is not designed to
lock the spindle for a cut. An independent clamp should be
provided in each instance, and the clamp must be loosened after
each cut before the work is rotated for another cut.
It is understood that when the center spindles shown in the
side view of Fig. 75 are not needed that they may be quickly
removed and a pair of vises or clamps applied to the knees CC
in the place of the centers and spindles. Or by a slight change
in the design the spindles may be pulled out and the castings D D
turned into vise clamps by the addition of another bit of metal
and a screw to each casting. In fact, the face of each of these
clamps may be readily fashioned into vises to remain perma-
nently in place for use when wanted, with no change whatever,
except to remove the spindles if the latter chance to be in the
way.
After you have made up this attachment and have gotten
it to working satisfactorily, then buy an old lathe bed and put
the attachment upon it, thereby leaving your lathe free for
its legitimate duties.

CHAPTER XV.
SPECIALIZING VS. GENERALIZING.
In most trades, and in some branches of blacksmithing, the
tendency is toward very narrow specialization. In fact, toward
doing only one thing. Thus, the smith sometimes finds it profit-
able to do nothing but shoe horses, while another man repairs
vehicles exclusively and shoes no horses nor does any repair work
whatever. Still another man confines himself to repair work
exclusively. But the tendency of smithing is to generalize, to
add repair and manufacturing branches; in fact, to become a
regular “department store" in the mechanical line where can be
obtained almost anything desired in the iron or woodworking
lines. To this end the smith is fast invading the field heretofore
occupied by the machinist, and he has always been a sort of
woodworker when occasion demanded.
A certain branch of smith work known as “machine black-
smithing” has heretofore been an unknown art to the average
smith, and this branch has been very closely allied to machine
work. In fact, a "machinist” (not a specialist in that line, lathe
hand, vise man, fitter, etc.) is usually a pretty good blacksmith,
well up in tool making and general forging, although he knows
little about carriage work and nothing about shoeing.
The smith who desires to progress should work into
machine blacksmithing as well as into lathe work. And both these
branches require the same study and preparation. A man may
be a good smith if he cannot even read and write, but he will be
a much better one, and earn better wages, if he can make and
read sketches and drawings. To that end let the smith learn to
draw, also to make simple patterns for castings.
MAKING DRAWINGS.
Many people have an entirely incorrect idea of the making of
drawings. Some of the schools seem to teach that when a pupil
can copy a drawing and make nice smooth lines that the pupil
knows how to make machine drawings. But nothing could be
127

128
THE SCREW-CUTTING LATHE.
further from the truth. In fact, two things are necessary for
the draftsman (or the smith who would make sketches) to know:
First, how to put lines on paper which will show the desired
object in such a manner that a smith can make it with no other
guide or instructions than the drawing in question. Second, the
smith-draftsman must know how to proportion the object so that
it will possess the necessary strength with the use of the least
possible material and at the same time be of such proportion
and finish as to present a pleasing appearance.
The man who can make a picture of a bolt or a nut may
not be able to name the proper dimensions for those objects, and,
on the other hand, the smith who knows how to make properly
proportioned bolts and nuts may be unable to express his ideas
on paper in the shape of a drawing or other sketch. In the former
case a good deal of study will be necessary; the strength of
materials must be mastered and the laws of machine design must
be studied. In the latter instance a very little study will fit the
smith to make intelligent drawings from which any man who
can read drawings can work easily and correctly. Two very
simple examples will illustrate this point :
DESIGNING AN EYEBOLT.
When a lathe is to be set up in your shop it proves very
handy to rig an eye-bolt in a beam overhead. By means of a rope
tackle the lathe is lifted from the wagon and deposited upon
rollers placed on the floor of the shop. The lathe weighs 4,200
pounds. A three-ton tackle is used, weight 200 pounds, giving
a six to one purchase on the lathe. How thick should the eye-
bolt be made to be safe to carry the load, yet not too large, which
would add to the cost of the bolt ?
The lathe load is 4,200 pounds. The tackle weighs 200
pounds, and with a six to one tackle, 700 pounds pull would be
necessary to balance the 4,200 pound load to be lifted. Something
must be added for friction, and 800 pounds may be taken as the
pull. This necessitates nine or ten men on the rope, and as they
may put 1,000 pounds on the rope should it become tangled,
then the eye-bolt should be made strong enough to withstand
a pull of 4,200 + 200 + 1,000, or 5,400 pounds.
The tensile strength of bar iron (soft steel) may be taken at
60,000 pounds to the square inch; that is, it will require a pull of

THE SCREW-CUTTING LATHE.
129
60,000 pounds to break a rod one inch square. To withstand a
pull of 5,400 pounds there will be necessary about III square
inch section of metal. But it must be remembered that III
square inch of metal will barely sustain a pull of 5,400 pounds.
In fact, it is expected to break under that pull, hence more metal
must be added until there is no doubt that the rod will sustain the
load under any conditions likely to arise. These conditions
must include possible poor quality of metal, defective forging of
the eye-bolt, defective thread, and perhaps a poor nut.
FACTOR OF SAFETY.
The excess of strength which must be thus provided is
known as the "factor of safety.” It varies according to the work
to be done. In unimportant places the factor is sometimes as
low as 2.
That is, twice the metal that would be broken by
the given load is allowed. In the case given above, where III
square inch of metal section is required .222 square inch would be
used. But a factor of safety of 2 is entirely too small. In steam
boilers 472 and 5 are the factors of safety usually employed. In
bridge work and in locomotive construction 10 is used as a
factor of safety, and this factor is used in all machine design
where metal may be subjected to shocks and other sudden strains. .
For the eye-bolt which we are designing a factor of 5 should
be used, which will bring the metal section up to 5 X II1 = .555
square inch.
The next problem of the smith designer is to
find what diameter of round rod will have a cross section of .555
square inch. To ascertain this point it is necessary to divide
-555 by .7854 and extract the square root of the quotient. This
gives a diameter of .84 inch. This corresponds closely to a rod
78 inch in diameter, which should be used for making the
eye-bolt.
Having ascertained the diameter of metal required for the
eye-bolt the rest is easy. The length is obtained from the con-
ditions to be complied with in using the bolt. If it is to pass
through a 6-inch beam, then a total length of 11 inches, as shown
by Fig. 78 will answer. Of this length 3 inches may be taken up
by the eye, 2 inches by the threaded portion, including the nut,
leaving 6 inches to pass through the beam.
The smith will readily see that the making of the picture or
sketch as shown by Fig. 78 is a very small matter. Once the

I 30
THE SCREW-CUTTING LATHE.
diameter of the rod and the length of the bolt are determined the
design of the eye-bolt is complete and it only remains to make the
picture in such a manner that any smith will be able to make the
bolt without any instructions whatever except those found upon
Fig. 78. It is understood, of course, that the thread is to be U. S.
HUB
1
**
n
- 2"-
K3"
K
-
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Fig. 78—Designing an Eyebolt. "Expansive" Blacksmithing.
standard, which is 9 to the inch for 7/8-inch bolts, hence no in-
struction is needed in that direction. The sketch also shows a
square nut but no washer, therefore the smith needs no instruction
in that direction. The eye is shown to be a long concern, there-
fore the smith need not spend time in rounding it up around a
punch. If a round eye were necessary it would be shown thus
upon the sketch.
In fact, as stated, every bit of information
needed for making the eye-bolt is to be found in the drawing.
DESIGNING A CASTING.
a
The same is true in making a design for a casting or for a bit
of lathe work. First determine the dimensions of the object by
the necessary calculations, then make the sketch or drawing to
show everything the workman needs to know. If a mechanic has
occasion to run after the draftsman and ask questions, there is
something wrong. Either the drawing is incomplete or the work-
man does not know how to read it properly.
For example, assume that the smith wants a pair of brackets
to bolt against a brick wall. A shaft must be hung there and the
brackets are to be arranged to receive each a rigid flat box or
pillow block, something as shown by Fig. 79. The bracket is also
shown by three views-plan, end and side elevations—Fig. 80
The writer will not give here the work actually done in designing
this bracket, but will give some of the necessary data and leave it
for the “expansive blacksmith” to work out the details for himself.
Let it be stated that the center of the shaft is to be placed 24
inches from the brick wall and that each bracket shall be safe

THE SCREW-CUTTING LATHE.
131
(factor of safety of 5) to carry 3,000 pounds vertical load at that
point.
The problem for the designer is, therefore, to determine the
length, breadth and thickness of the vertical and level portions of
HA
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Fig. 79-Cast-iron Wall Bracket.
the bracket. There will be four 12-inch bolts for fastening the
box to the bracket. But the size of the two bolts which fasten the
bracket to the wall must be calculated. When cast iron is sub-
Seat for Box.
Fig. 80-Bracket Separated from the Wall and Box.
jected to a pull it is under tensile strain, and not over 26,000
pounds to the square inch should be permitted. When cast iron

132
THE SCREW-CUTTING LATHE.
comes under compression strains, then a much greater figure is
permitted.
REFERENCE BOOKS.
At this stage of the game it is up to the smith to obtain one
or two good reference books in mechanical engineering. To
properly design the bracket noted above the smith must have com-
plete data of the strength of materials, the moment of inertia, the
strength of beams and other data. For this purpose a book like
Kent’s “Engineer's Pocket Book” is necessary. There are several
good books of similar character on the market, and doubtless the
publishers of this book will procure for any reader, upon request,
a suitable reference book for the purpose. The smith must have
at least one book of this kind, and he will find frequent use for it
right at the beginning. As the “expansive” work progresses the
smith will find use for two or three books of similar character,
though in a slightly different field. Trautwine's “Engineer's
Pocket Book” will answer all questions which may arise concern-
ing building problems. It tells all about geometry problems, and
covers all work the smith will ever get up against in building a
shop, tinning the roof, calculating foundations, drawing, building
railroad switches or anything of that kind. Add to the above
books, later, perhaps, one or more good books on electrical en-
gineering and the smith will be ready to “meet all comers.'
The smith, by the addition of a screw cutting lathe to his
shop tool equipment, has found that he must at once learn three or
four trades additional to that of blacksmith. Instead of remain-
ing a mere shoer of horses and maker of wagons he must expand
into a machine blacksmith, a pattern maker, an iron founder
(molder) and a machinist. As far as concerns the machine black-
smithing and the lathe work, the smith can be trusted to make his
way with little trouble.
a
PATTERN WORK AND MOLDING.
It is in the lines of pattern making and molding that the
smith needs aid and instruction. In pattern making that he may
be able to fashion correct patterns for such castings as he may
need to keep his lathe work agoing, and in molding that he may
be able to properly design and arrange such patterns so as to get
good castings from them. Cast iron is a very peculiar material to

THE SCREW-CUTTING LATHE.
133
handle and the design has much to do with the soundness of the
castings also with the cost or waste of iron in the castings in
question.
It is possible—yes, quite easy—to put twice the necessary
metal into a casting and still have it prove too weak for the pur-
pose intended. It is, then, necessary for the smith to study the
behavior of cast iron in order to know how best to distribute the
metal. Certain shapes and proportions are also necessary in order
to make the molten metal form into a solid casting when cooled.
If certain proportions are not followed the castings will crack or
break to pieces through internal strains.
Certain other shapes and proportions must be given to every
pattern in order that it may be properly removed from the sand
during the operation of molding. Fig. 81 shows this matter
DO
b
Fig. 81-"Draft” in Patterns.
plainly. The novice in pattern making who needs a cast iron
circle with a round hole through its center will probably turn out
a pattern with a section like that shown at A. The circular por-
tions of both pattern and hole are made square with the flat faces
of the pattern, and the molder will have no end of trouble in get-
ting the pattern out of the sand. The outside of the pattern will
cling to the sand and probably it will shear off the top corner of
the mold when the last corner of the pattern leaves the mold.
"DRAFT" IN PATTERNS.
That portion of the mold which forms the “core,” or which
is contained in the hole in the pattern, will also give trouble. The
molder puts two or three nails in the sand packed into the hole
in question, but even then the pattern will be almost sure to tear
off the top corner of the sand and make necessary a tedious patch-
ing and building up of the mold after the pattern has been taken

134
THE SCREW-CUTTING LATHE.
out. To obviate this difficulty and remove the trouble entirely it
is only neccessary to taper the pattern as shown at B, Fig. 81
Then, in molding, the pattern is so placed that the larger flat side
will be on top, the smaller side C at the bottom of the mold.
Always, before commencing to “draw" a pattern the molder
will thrust a screw or a sharp pointed rod into the pattern and
strike sidewise on the rod, just above the pattern, several smart
but light blows with a small bit of metal—a spike or a bit of rod.
This causes the pattern to free itself from the sand. The molders
call this action “rapping” the pattern and it should be done cau-
tiously and with a good deal of care, otherwise the mold will be
made too large by excessive rapping and the truth of the casting
seriously affected.
When large patterns are made it is customary to add one-
eighth inch to each foot of every dimension. This quantity is
called the "shrink” of a pattern or a casting and it just makes up
for the amount which the casting “shrinks” or contracts during
the act of cooling. In making very small patterns no "shrink” is
allowed, for the reason that the rapping of a pattern usually en-
the mold just about enough to make up for the “shrink" of
the casting.
The taper which should be given to a pattern—the "draft,”
as it is called in the foundry-need only be very slight. One-
sixteenth of an inch on each side of a pattern will allow one-
eighth of a inch clearance when the lower edge of the pattern
comes to the top of the mold, and this amount of “draft” will
make it easy to get a pretty large pattern out of the sand without
trouble. And here comes up another nice point in making pat-
terns. It is usual to so arrange the draft on a pattern that the side
which is of the most importance shall be at the bottom of the mold
when the iron is poured in. The bottom of a casting is always the
best side and is the most free from blow holes, slag or other
imperfections with which castings may be afflicted.
larges
CASTINGS BROKEN BY POOR DESIGNING.
As regards the cracking or breaking of castings through
poor design, this matter is graphically shown by Figs. 82 and 83.
In Fig. 82 the casting is for a grate, but the principle is the same
as for a pulley or a gear. When a pattern is made with a heavy
circular ring connected at intervals by bars, or continually by a

THE SCREW-CUTTING LATHE.
135
web or disc, it is very certain that the casting will come out of the
sand broken in one or more places. Fig. 83 aids in understanding
why such breakage occurs. The heavy circular rim holds the heat
Fig. 82-The Casting that Broke Because of Faulty Design.
much longer than the small bars comprising the lattice work of
the grate, so that the rim is still hot after the grate has cooled.
Then, when the ring cools, the grate portion is crushed and is
forced up into a more or less conical shape until the bars break or
until the cooling strains are equalized. Should the grate be made
thick and the outside ring thin, then the ring would cool first and
the slow cooling bars would pull themselves in two during the
Fig. 83-Section of a Casting That Broke.
strain adjustment. It is for this reason that castings must be so
proportioned that cooling strains will not distort them.
The study of an engineering handbook will enable the smith
to properly design a casting that the strains may be properly dis-
tributed This is important to the smith because it is quite
possible for many a smith to set up a small cupola and melt iron
and make the casting required. This is another “expansive"
method by which the smith can increase his cash account when
there is not a foundry near at hand.

CHAPTER XVI.
SPEEDING A CIRCULAR SAW.
a
It frequently happens that the power-using smith finds him-
self "up against it” when a new machine is to be put into the
shop. Perhaps the lathe and drill press are working profitably
and it is found necessary to put in a circular saw. Such a tool
will require power enough to drive half a dozen lathes and the
speed of the saw is so much faster than is required at a screw-
cutting lathe that serious complications arise in obtaining suffi-
cient power to drive the machines and to get the proper speeds
when the necessary power is to be had. If a circular saw is to be
set up its speed must first be determined. The "rule of thumb"
for speeding a circular saw is to run it a mile a minute. That is,
the periphery of the saw (the toothed circumference) should
travel at about 5,280 linear feet to the minute. If a 10-inch saw
is to be used the speed of the saw arbor should be about 1,960
revolutions to the minute. If it is to be a 20-inch saw, then 980
revolutions will be enough to give the same tooth velocity.
According to the above rule, a 6-inch saw should make
3,350 turns to the minute, while a 36-inch saw should run only
about 540 turns, while a 48-inch log saw should trundle along to
the tune of only about 400 revolutions to the minute. But the smith
will get into difficulty at the start. The saw bench he is intend-
ing to set up is fitted with saws ranging from 6 to 18 inches in
diameter, and evidently the speed which will be right for one
size of saw will be wrong for some of the other sizes. It is for
the above reason that some saw arbors are made with a stepped
pulley to receive the driving belt, in order that the small saws
may be driven at greater speed than the larger saws, thereby ap-
proximating the correct speed for each size of saw-a rough ap-
proximation, to be sure.
136

THE SCREW-CUTTING LATHE.
137
While the 6-inch saw should run 3,350 revolutions, the
18-inch saw should be speeded at only 1,110 revolutions. In
case like this it is well to under-speed the small saw considerably
and over-speed the large saw only slightly, giving the saw man-
drel a speed of say 1,660 revolutions in order to obtain the best
average results. At 1,660 revolutions a 12-inch saw would have
the proper speed and all other sizes would run either too fast or
too slow, according to their diameter. It is probable that saws
about 12 inches in diameter would be used more than any other
size, hence that speed is the nearest right.
If it should be desired to speed up the mandrel for a smaller
saw the speed would be too great for the large saw, its rim
would stretch under the tremendous centrifugal force and the
saw would "wander” around from side to side, instead of stand-
ing up stiffly and cutting a straight kerf. If it is found necessary
to speed up for a small saw the larger saws may be hammered
for the high speed at which they run all right after the center of
the saw had been stretched by hammering, but saws thus ham-
mered would not run well at a slower speed than they were ham-
mered for.
Having thus found that it may be necessary for the smith to
change the speed of some or of all the shafting in the shop when
another machine is to be put in, it will be in order for the smith
to provide pulleys which will give the proper speed to shaft or
to machine. It may be found necessary to provide a pulley 48-
inch diameter, 8-inch face, to fit a 2 7-16-inch shaft. Such a pul-
ley may be found at the nearest machinery depot or hardware
store. If so, buy it by all means. Probably a wooden pulley will
answer all requirements and its cost will be only about one-half
that of a cast-iron pulley. Sometimes wrought steel split pulleys
are obtainable. These are very desirable pulleys and give excel-
lent service.
MAKING A PULLEY.
But perhaps there is no pulley in the store. More frequently
there is no store, and the smith must hie himself to some more or
less distant foundry which happens to have a pulley pattern of
the required dimensions. But there is a way by which the smith
with a lathe can get up a fine pulley even cheaper than the price
of a wooden one. Let him make up a pattern of a flanged hub,

138
THE SCREW-CUTTING LATHE.
something as shown by Fig. 84. This pattern may be turned up
in the screw-cutting lathe. It is more fully shown by the sec-
tional view in Fig. 85.
To make this pattern drawings are first gotten out and the
several dimensions determined as a matter of course. The pul-
ley is to consist of several layers of
dressed lumber, each layer with the
grain crossed against the adjacent
layers, and glued and nailed firmly
together. The thickness of the web
thus made to be about 372 inches, and
consisting of four thicknesses of 78-
inch stuff. The remainder of the pulley
face to be formed of six layers, three
Fig. 84—Flanged Pulley Hub.
on each side, of 7/8-inch segments,
nailed and glued in place as shown by Fig. 8.
The diameter of the cast-iron hub is determined by the diam-
eter of the shaft on which the pulley is to be placed. In this case
it is 2 7-16 inches, therefore the hub must be large enough to
bore that diameter and still possess sufficient metal to stand
the strains of work. In this case another matter determines the
thickness of the "wall” of the hub, as the section outside the
1
o
.
A
UNAWWWWW
B
Fig. 85—Sectional and Side View Flanged Pulley Hub.
bore is called. The diameter of set screw is the determining fac-
tor. As the pulley is to be 48 inches in diameter and must carry
an 8-inch belt there will be exerted to shear off the set screws a
power of 8 x 40=320 pounds; the pull of the belt, exerted
through a leverage of 24 inches, against another leverage of
about 1/4 inches (half the diameter of the shaft), about 19.2:

THE SCREW-CUTTING LATHE.
139
320 X 19.2 equals about 6,150, slide rule calculation, and allowing
a factor of safety of 5, about 30,700 pounds of shearing strain for
the set screws to hold. It is never well to subject set screws to
more than 45,000 pounds to the inch strain in single shear, as
set screws are exposed, therefore it will require 30,700 divided by
45,000, or 0.685 square inch of set screw section.
SIZE OF SET SCREWS.
A 58-inch set screw is about 1/2-inch in diameter at the bot-
tom of the threads (0.507) and its sectional area is about 0.2
square inch. To obtain a total area of 0.685 divided by 0.2,
which equals 3.42, showing that more than three 58-inch set
screws are needed, therefore four must be put in. As 58-inch
screws are to be used the wall of the hub need only be thick
enough to serve as a nut for the screws, the thickness of wall
needs be equal to the diameter of the screw, or 5/8-inch. Thus
twice 5/8-inch added to 24/2 inches, gives 334 inches as the neces-
3
MITTITT
Fig. 86—Sectional and Side Views of a Built-up Pulley.
sary thickness of the hub. As it is desirable to get rid of frac-
tional measurements when just as well without them the drafts-
man would call the hub 4 inches in diameter. In all designing,

140
THE SCREW-CUTTING LATHE.
care should be taken to keep to even dimensions, and it can usually
be done without increasing the cost.
The length of the hub should be such as will permit the set
screws H, H, and G, G, of the sectional view in Fig. 85, to be
placed outside of the solid web of the pulley. The smith can de-
termine this dimension for himself. The flange, C, is next to be
figured and dimensions obtained for it. Here is a piece of metal
which must stand the strain of several bolts in single shear the
same as set screws, only the bolts being further from the center
of the shaft the leverage is reduced. The bolts must be placed
far enough away that the nuts can be turned outside of the hub,
say 2 inches away therefrom, making the total distance about 4
inches from the center of shaft. Therefore the leverage for these
bolts will be 24 divided by 4, or 6. The strain on the bolts will
therefore be 320 x 6 or 1,920 pounds, and with a factor of safety
of
5 the strain amounts to only about 9,600 pounds, against 30,-
700 pounds which the set screws had to withstand. It will be
seen that the bolts can be quite small, but they should not be made
less than 7-16-inch or 1/2-inch on account of the danger of twist-
ing them off when screwing up the bolts to tighten the wooden
web of the pulley.
THICKNESS OF FLANGE.
For the same reason the thickness of the flange should not
be made less than 12-inch, for fear that it be broken by setting
up some of the bolts while the wooden web does not bear fair
upon the flange, thereby setting up strains foreign to the work
the flange is designed for. The total diameter of the flange
needs to be considerable in order to secure a good bearing of
the web against the iron and make the pulley run true. A dis-
tance outside of the bolts equal to the distance from bolts to
hub would appear to be about right. This brings the bolt circle
8 inches in diameter and the flange 12 inches in diameter, making
what appears to be a well-proportioned design.
The smith now has the design of the hub all figured out and
it is an easy matter to lay it down on paper. The next thing is
to proceed with the pattern, which should be made of well-sea-
soned white pine or mahogany. Bay wood is used a great deal
for patterns, and they are charged for as made of mahogany.
Never try white wood for patterns. It will not work well if to

THE SCREW-CUTTING LATHE.
141
be used after being kept for a while. Patterns made from white
wood will twist out of shape and become useless.
SPLIT PATTERN-CORED HOLES.
This pattern may be molded if made all in one piece, but
it will work much better if made in two pieces. It had best
be divided cross wise as shown at A, Fig. 85. By dividing in the
middle of the flange all the bolt holes may be made by green
sand cores, whereas if the pattern be divided longitudinally,
through a, b, sketch A, Fig. 85, the holes in the flange must be
a
drilled, as they cannot be cored when the hub is thus divided.
In practice, the piece d should be turned up, making the
recess at f to receive a corresponding projection on piece e.
The holes in the flange are then made tapering as shown in
both views, and two projections are left, one at either end of the
hub, as shown by a and b. These projections are called “core
prints” and are made the same diameter as the hole desired
through the hub. As the hole must be cored to 2 7-16-inch,
some metal must be left for machining, therefore a core about 2
inches in diameter should be provided for, which means that the
core should be of the same diameter as the prints and of a length
equal to the distance from end to end of prints a and b.
For special cores it is necessary to make a “core box,” in
which the cores will be made, but for round cores no box is
necessary, as every foundry is supplied with these boxes and keeps
round cores of all sizes made up in advance, which may be cut
off to the required length when wanted.
CORNERS ON PATTERNS.
In making the drawing for this casting, and for any other
casting, the smith should always avoid as far as possible a square
corner where two surfaces come together. Note in the sketches,
particularly at A, Fig. 85, the connection between the hub d and
flange c. There is shown a rounded corner like that at A, Fig.
87. Never permit or show a corner like B, Fig. 87. Such a
corner is weak and fosters cooling cracks in the casting which
frequently spoil castings containing them. Whenever two sur-
faces intersect in a casting see that the junction is nicely curved
with as long a radius as possible between the two. Always
specify on the drawing the radius of any corner.
The corner in
question is marked for a fillet of 1-6-inch radius.
'

142
THE SCREW-CUTTING LATHE.
When two planes are to be joined in a pattern drawing hold
up the hand and note the fine curve joining two fingers when they
are slightly parted, as is shown in Fig. 88. It is a safe curve
LL
L RAD. 18"
А
B
с
D
Fig. 87-Corners on Drawings and Patterns.
pattern to follow at all times. In making some patterns it is easier
to make the corners square and sharp and fill them afterward to
the desired radius. In cases of this kind the corners would be
put together square as at B, Fig. 87, and afterward filled with
leather, beeswax or putty. The methods are preferable in the
order named. A method of filling a corner
with beeswax and a hot iron rod is shown
by Fig. 87, at C. The wax is melted in and
molded and smoothed with the heated rod,
after which the surplus wax is removed.
Putty is used in the same manner and set
with the same tool, except that, with putty,
the tool does not have to be heated for its
application to the pattern. The leather
fillets, C, Fig. 87, may be purchased by the
yard of any desired radius and it is only nec-
essary to wet a piece of leather fillet, apply
a little glue and rub the fillet into the corner
Fig 88—Nature's Design
for Fille ts.
with the same round tool described above.
This tool need not be heated for the leather.
PAINTING PATTERNS.
In making a pattern where core prints are used it is custom-
ary to paint the body of the pattern black, then when there are
core prints paint them red, as a guide to the molder in setting the
cores.
In making up the pulley the several layers of lumber should

THE SCREW-CUTTING LATHE.
143
all be gotten out, fitted and marked, then put in a dry house or
over a steam boiler until thoroughly hot clear through. The hot
glue should be quickly applied and the several layers of wood
nailed together. The wood must be hot enough to keep the glue
melted while the putting together is being done. After the pulley
is finished and has become dry, it should be mounted on a piece
of shaft and turned smooth all over.
The shaft with the pulley upon it should then be placed on
stiff level strips of iron, and the pulley balanced so it will stay in
any position without trying to revolve a heavy side down. If
such a thing happens, and it is the rule rather than the exception,
drive nails into the light side of the pulley until it will lie in any
position without the least tendency to rotate. Sometimes it is
necessary to bore holes and insert pieces of iron or lead to bring
the pulley to a balance.
BORING THE HUB.
One very important operation has been overlooked—that of
boring the hub, but the smith is prepared for that operation once
he finds a way of mounting the hub upon the face-plate of the
lathe. But that operation is really very simple. All that is nec-
essary is three or four small blocks. Place them between the hub
flange and face-plate and bolt the hub in place by means of bolts
through the flange. Place the block C (Fig. 46, page 83) close
to the bolts and tighten up, adjust and pack under one or more of
the blocks until the working face of the flange and the hub both
run as true as possible. Then the hub is ready to be bored out
with an ordinary tool or to have a chucking drill passed through
it—and that finishes the lathe part of the job.
The smith in making the pattern of the hub will give it a
little taper or draft in the direction it is to be pulled out of
the sand. Thus the smith finds it necessary to think out the
manner in which the molder will make up the mold and how the
pattern must be drawn out of the sand. The smith must also
bear in mind that the best side of any casting will be downward
when the iron is poured into the mold, and will govern himself
accordingly in giving draft. In this casting the side of flange ad-
jacent to long portion of hub should be the best side, hence the
pattern is arranged to be molded with that side of the flange
downward when the iron enters the mold.

CHAPTER XVII.
SHAFTS, PULLEYS AND BELTS.
In almost every shop where power has been installed there
is to be found one or more belts which are always giving trouble,
while the rest of the belting does the work easily and satisfac-
torily. There is a reason for the failure of every belt, and a
close study of the conditions under which the belt is required
to give service will surely reveal the cause of the trouble.
Some of the catalogues issued by the builders of power
transmission machinery contain tables showing the power to be
derived from a belt of given width on a pulley of stated diameter.
These tables are usually calculated for a speed of 100 revolu-
tions of the pulley each minute. To find the belt power for any
other speed simply divide the given power by 100 and multiply by
the given speed, or, which is a little easier, multiply the given
power by the speed and cut off the two right-hand figures; the
remaining figures will be the power which should be transmitted
at the given speed.
The tables referred to usually are based upon a belt pull of
88 pounds to the inch of belt width for double belts and 66 pounds
to the inch of width for single belts. It has for some time been
the practice of the writer to discard the published tables alto-
gether and calculate the power required separately for each belt.
The writer has designed several factories in which there was no
such thing as a belt which slipped or failed to do all the work
expected from it. The secret or rather the cause of this invariable
good service from all the belts was due to one thing: instead of
allowing 88 pounds pull to the inch of belt width the writer allows
only 40 pounds and this, too, for double belts. As for single belts,
they are never considered—all the belts used are double.
WIDTH OF BELTS.
Suppose power is being put into the shop and a ten-horse
motor is to be belted. There usually is a wheel on the motor
shaft, but sometimes that must be supplied by the purchaser, in
144

THE SCREW-CUTTING LATHE.
145
which case he is more at sea than ever as to the proper width
of belt to use. Ascertain the speed at which the motor will run
and the rest of the calculations are rather easy.
Ten horse-power means 10 X 33,000 pounds lifted one
foot high in one minute, or 330,000 foot-pounds. If the n'otor
makes 200 revolutions each minute, then there must be supplied
3.30,000 · 200, or 1,650 foot-pounds to each revolution of the
motor shaft. Assume the diameter of the wheel to be placed on
the motor shaft and calculate the width of belt necessary, then
if the width thus found be out of proportion it can be changed
by increasing or diminishing the diameter of the wheel in
question.
First, however, the 1,650 foot-pounds to the revolution may be
diminished by dividing it by 40, which will bring the answer
directly in terms of inches of belt width. Thus, 1,650 - 40 equals
41!4, which is the product of the pulley circumference in feet
into its width in inches. If the given number be divided by 3.141
the resulting quotient of 13.1 will be the product of the pulley
diameter in feet and the belt width in inches. Thus, if a 3-foot
pulley is used the belt width should be 4.37 inches (slide rule
calculations). Or, if an even inch width of belt is desired, the
pulley diameter should be 39.1 inches. About 40 inches diameter
by 4-inch face would be the proper thing.
Should it be found that the speed imparted to the line shaft
would be too great with the 40-inch pulley, it is only neces-
sary to divide 13.1 by the width of the belt, or by the diameter of
pulley wanted, in order to settle the matter satisfactorily. Thus:
13.1 ; 5 equals 2.62 feet, or 311/2 inches. Or, if a 24-inch pulley
is wanted, the necessary belt width to carry 10 horse-power will
be 13.1 ; 2, or 6.55 inches. A 7-inch belt would do the business
on a pulley 227/2 inches in diameter.
COST OF PULLEYS AND BELTS.
It is an easy matter to carry this scheme of calculation
to all the pulleys throughout the shop and thus obtain the best
possible form of transmission. But there are two other things
to be taken into account when calculating the pulleys for a shop,
and those things are: the cost of the pulleys and belts. Large
pulleys cost more than small ones, and wide belts are much more
costly than narrow ones, and these points must be carefully cal-

146
THE SCREW-CUTTING LATHE.
culated and compared with each other in order to select the
pulleys and belts which will carry the required power with the
least outlay for pulleys and belts.
A 40-inch pulley with a 4-inch face may cost $14.10, while
at the same rate of cost a 225/2-inch pulley with a 7-inch face
should cost $7.85. It is the cost of belt which makes the small
wide pulley transmission a costly thing. Estimating the aver-
age length of a belt to be 25 feet, and the cost of a 4-inch belt to
be 80 cents a foot, the cost of a 7-inch belt will be about $1.30
a foot, or $20, and $32.50 for the two belts of 25 feet each in
length. This shows that the saving of $6.24 in buying the smaller
pulley was offset by an additional expenditure of $12.50 in the
cost of the belt, thus saving exactly half, or $6.25, by purchasing
the larger diameter pulley with the narrower face and the lesser
belt. But there is another factor which has not been taken into
account. The belt must run over two pulleys and we have calcii-
lated the cost of only one. Should the belt run on a pulley of the
same diameter on the driven shaft, then the loss in buying a large
diameter pulley would exactly equal the saving in procuring the
narrow belt, and it is evident in this case at least that it would
make no difference which form of transmission was used.
Thus the length of belt enters twice more into the calcula-
tions, for with the large wide pulleys there will be a little more
belt length than with the small wide face pulleys, and if the dis-
tance between shaft centers be greater or lesser than the equal
cost figure, then the saving by using either large pulleys or wide
belts would have to be calculated for each shaft distance and
pulley diameter.
SLIPPING BELTS.
All other things being equal, the pulley of large diameter
should be used for the reason that a belt is much more apt to
slip on a small than on a large pulley. The surface in contact
between belt and pulley is much greater on pulleys of large diam-
eter than on small ones, hence the slip comes on the smaller pulley
every time. There should be a limit to the size of pulleys used
in transmitting power, especially a limit as to the smallest diameter
which should be used. The writer, in a somewhat extensive
practice, has for several years followed strictly the rule never to
put a pulley less than sixteen inches in diameter on any shaft

THE SCREW-CUTTING LATHE.
147
which is to drive another or a machine. Of course this does
not apply to pulleys on machines, for these are at "owner's risk,”
and the maker of the machine is responsible for their behavior.
It is a mighty good and safe rule to follow that a pulley should
never be used with less diameter than twice the belt width, and bet-
ter three times. Use this rule and give only forty pounds load to
each inch of belt width and you will never have a belt fail to do
all that is asked from it.
Small pulleys must be used on some machines, and when
such is the case increased adhesion can frequently be obtained
when the belt must run at exceedingly high speed by turning
shallow grooves or channels in the face of the pulley, the channels
being made abou 18-inch wide and 1/2 inch apart. Holes are
drilled about two inches from each other along the groove, around
the entire circumference of the pulley in each groove. The object
of the grooves and holes is to let the air escape which would other-
wise be caught between the fast running belt and pulley surface.
The arrangement above described has been made the subject
of one or more patents and is known as the “pneumatic pulley."
Just how much stock to take in this device each user must decide
for himself.
There is quite a paradox in the action of pulleys and belts,
one man claiming that the more surface contact between pulley
and belt the more the belt will pull. Therefore the man who
increased the contact to the very limit by carefully polishing the
face of the pulley so that the belt might come surely in contact
with as much of the iron as possible totally failed in his calcula-
tions, for when the pulley failed to drive the belt load, and slipped
merrily around, turn after turn, a bystander promptly cured the
trouble by taking a bastard file in both hands and ruthlessly
spoiling the beautiful surface on that pulley by draw-filing the
entire face. Then the belt went right to business and never
slipped an inch.
BELT ADHESION.
The “pneumatic” pulley is another contradiction of the theory
that the greater the contact between pulley and belt the greater
will be the power transmitted. The theory fails here by the fact
that cutting away one-fourth the pulley face surface by grooves
and holes increases the adhesion of the belt. In view of these

148
THE SCREW-CUTTING LATHE,
facts it is well to cut out the statement that the power of a belt
increases according to the increase of contact between pulleys and
belt. Instead just write: “The power of a belt increases with
the arc of contact, not with the increase of surface.” With this
supposition the paradox disappears and nothing but a statement
of fact remains. By "arc of contact” is meant the distance the
belt laps around the pulley. It seems to make no difference what
kind of a surface there is, unless it is so polished that the belt
cannot get hold of the pulley surface. This is proven by running
a belt on a spur gear used as a pulley. It is found that the gear
imparts fully as much power to a belt as if a pulley were used.
BELT SPLICING.
The proper method of joining together the ends of a belt is
another
very
much discussed subject and one which will be in dis-
pute as long as belts are used. The writer is, once for all, and all
the time, in favor of a cement splice, thus making the belt an
endless one. But where this is done there must be some way
of
tightening the belt, for it is too much work to take up a belt with
a splice in it. Either a “binder” or tightener” must be used or
the driven machine must be so that it can be moved forward or
back to accommodate the belt. Electric generators and motors
are all built thus. When the belt needs tightening it is only
necessary to tighten up a screw and the machine slides right back
until the belt is sufficiently tight.
Next to the "endless” belt comes the belt with the ends joined
by means of “Bristol” belt hooks. This fastening is a thin piece
of steel with the edges cut into teeth and turned square with the
body of the strip, which is made in lengths of one-fourth to three
inches, varying by quarters of an inch, so that pieces enough may
be placed end to end to reach across the width of any belt. To
apply these fastenings the ends of the belt are cut square, then
placed smoothly together on the end of a block of soft wood. It
is better to hold the belt ends firmly upon the block by means of
a nail or two in each belt end. Select such sizes of fastenings as
will reach across the belt to within one-fourth inch of each edge.
Put the pulley side of the belt next to the block, then with a small
hammer carefully drive the fastenings into the belt, keeping the
rows of teeth equidistant from the splice. Drive the fastenings
clear down to the belt, then remove from the block, turn the belt

THE SCREW-CUTTING LATHE.
149
over and place it on a piece of iron, then clinch the small steel
teeth, keeping them all pointed toward the joint or splice and not
letting any of them bend down in other directions. After the
teeth have been all bent down take a heavier hammer and drive
the teeth below the surface of the belt, so they will not touch the
pulley. Upon the driving down of the points depends the smooth
running of the belt.
These fastenings are made in several sizes and weights. The
Nos. 10, II and 12 used on four-ply, five-ply and six-ply rub.
ber belts respectively, No. II being an all-around fastening if no
other size is to be provided. These fastenings take up but about
one inch of the length of the belt, hence when they are cut out-
they never can be used but once—they destroy only one inch of
the belt length.
BELT LACINGS.
The next choice to the Bristol belt hook is the time-honored
lacing of sheepskin or horsehide, and the Blake belt stud, a small
affair made of brass with a T-head on either end of it. Both
these studs and the Bristol fastening do not remove any of the
belt, hence the joint or splice made with them is the strongest pos-
sible. When a belt is punched for lacing some of the material is
removed by the punch, therefore the belt is weakened the exact
amount of material thus removed, hence small holes should always
be made when a belt is to be laced and the necessary strength of
lacing provided by punching two rows of holes, one behind the
other, thus doubling the amount of very narrow lacing which
may be used, without increasing the amount of belt cut away by
punching
And now just a few words in regard to the kind of belt the
smith should purchase for use in the shop. There are three kinds
of belting, leather, rubber and "impregnated stitched cotton.”
The latter is known locally as “Gandy,” “Rub-oil,” “Mount
Vernon," and by a dozen other names. This belt was patented by
Mr. Gandy and took his name. Since the patents expired numer-
ous manufacturers have given their attention to this kind of belt,
with disastrous effects upon the quality of the belts turned out.
QUALITY OF BELTS.
These belts are strong, stand the weather well and can be
run in wet places the same as rubber, but the great fault with

150
THE SCREW-CUTTING LATHE.
them is their tendency to stretch. If used on shafts with a good
distance between centers, with a load of only 40 pounds pull to
the inch of width, then Gandy belts will run well and give little
trouble by stretching. But overload them or use them on pulleys
close together and they give a great deal of trouble, need to be
continually taken up, and slip upon the least provocation. The
writer has equipped many factories with them and will do so
whenever it is possible to use the belts at a maximum of 40
pounds pull to the inch. Under other circumstances let these
belts severely alone.
Leather belts are the most costly of all if they are properly
cut out of the back of the hide or skin. The best belts are known
as “short lap” and no piece of leather in one of these belts is
more than four and one-half feet long. In belts other than short
lap the pieces run up to seven and even eight feet in length.
These should be avoided.
Rubber belts are made of cotton duck similar to the "Gandy"
but coated with rubber instead of being filled with oil. The great
defect of the “rubber" belt is the lack of rubber in its construction.
The increased scarcity of rubber leads to substitution of other
things, to the great detriment of the belt.

CHAPTER XVIII.
THREADING PIPES IN THE LATHE.
One thing which the smith with a screw-cutting lathe will
surely be sooner or later called upon to do is to thread sundry
pieces of steam pipe. Indeed, it may have to be done in the course
of the regular shop work and it is well to be prepared in advance
for anything of this kind.
But before telling how to thread pipes in the lathe it will be
well to tell how pipes are dimensioned. When we say "a half-inch
pipe” little idea of the actual dimensions of that size of pipe is con-
veyed to the person unaccustomed to handling or working pipes,
for the reason that“half-inch pipe” is not one-half inch in diameter,
either inside or outside. The nominal diameter of pipe is given in
the dimension "half-inch pipe," not the actual diameter, is always
larger than the nominal diameter, especially in the smaller sizes.
Pipe commonly known as "one-half” is actually 0.623 inch
in diameter inside and 0.840 inch diameter outside, hence the
term “half-inch pipe” is apt to be misleading unless the user hap-
pens to be posted in regard to pipe sizes. The following table con-
tains so much valuable information concerning steam, gas and
water pipes that it is given in its entirety, instead of being
abridged, as was the first thought of the writer :
DIMENSIONS OF STEAM, WATER AND GAS PIPES.
....
2.5
Length of Pipe
Per Square Length
Threads
Foot of Contain-
Diameter Actual Το
Circumference Transverse Area
Surface ing One Weight
Nomi- Ex- In- Thick- the
Ex- In-
Ex-
In-
Ex-
In-
Cubic Per
nal ternal ternal ness Inch Pitch ternal ternal ternal ternal Metal ternal ternal Foot Foot
.125 .4 .27 .07 27. .037 1.27 .85 .13 .06 .07 9.44 14.15
.24
.25 .54 .36 .09 18. .056 1.7 1.14 .23 .1 .12 7.07 10.49
.42
.375 .67 .49.09 18. .056 2.12 1.55 .36 .19 .17 5.66 7.73 751.2 .56
.5 .84 .62.11 14. .071 2.64 1.96 .55 .3 .25 4.55 6.13 472.4 .84
.75 1.05 .82 .11 14..071 3.3
2.59 .87 .53 .33 3.64 4.63 270. 1.11
1. 1.31 1.05 .13 11.5 .087 4.13 3.29 1.36 .86 .49 2.9 3.64 166.9 1.67
1.25
1.66 1.38 .14 11.5 .087 5.21 4.33 2.76 1.5 .67 2.3 2.77 96.2 2.24
1.5 1.9 1.61 .14 11.5 .087 5.97 5.06 2.83 2.04 .8 2.01 2.37 71.7 2.68
2. 2.37 2.07 .15 11.5 .087 7.46 6.49 4.43 3.36 1.07 1.61 1.85 42.9 3.61
2.87 2.47 .20 8. .125 9.03 7.75 6.49 4.78 1.71 1.33 1.55 30.1 5.74
3
3.5 3.07 .22 8. .125 11. 9.64 9.62 7.39 2.24 1.09 1.24 19.5 7.54
3.5 4. 3.55 .23 8. .125 12.57 11.15 12.57 9.89 2.68 .95 1.08 14.6 9.
4. 4.5 4.03 .24 8. .125 14.14 12.65 15.9 12.73 3.17 .85 .95 11.3 10.66
5. 4.51 .25 8. .125 15.71 14.16 19.63 15.96 3.67 .76 .85 9. 12.34
5.
Frraiciosos como
4.5
5.56 5.04 .26 8. .125 17.48 15.85 24.31 19.99 4.32 .69 .76 7.2 14.5
6. 6.62 6.06.28 8. .125 20.81 19.05 34.47 28.89 5.58 .58 .63 5. 18.76
7. 7.62 7.02 .30 8. .125 33.95 22.06 45.66 38.74 6.93 .5 .54 3.7 23.27
8. 8.62 7.98.32 8. .125 27.1
27.1 25.08 58.43 50.04 8.35 .44 .48
2.9 28.18
3. 9.62 8.94 .34 8. .125 30.24 28.08 72.76 62.73 10.03 .4 .43 2.3 33.7
10.75 10.02 .37 8. .125 33.77 31.48 90.76 78.84 11.92 .35 .38 1.8. 40.06
11. 11.75 11. .37 8. .125 36.91 34.56 108.43 95.03 13.4 .32 .35 1.5 45.02
12.75 12. .37 8. .125 40.05 37.7 127.68 113.1 14.58 .3 .32 1.3 48.98
13. 14. 13.25.37 8. .125 43.98 41.63 153.94 137.89 16.05 .27 .29
1. 53.92
14. 15.
14.25 .37 8. .125 47.12 44.77 176.71 159.48 17.23 .25
.27 .957.89
15.
16. 15.43.28 8.
50.26 48.48 201.06 187.04 14.02 .24 .25 .8 47.11
16. 17. 16.4 .3 8. .125 53.4 51.52 226.98 211.24 15.74 .22 .23 .7 52.89
17. 18. 17.32.34 8. .125 56.54 54.41 254.46 235.60 18.86 .21 .22 .6 63.32
10.
12.
ooo oo os
151

152
THE SCREW-CUTTING LATHE.
It will be noted that pipes are invariably larger than their
nominai diameters, especially in the smaller sizes. This is very
confusing at first to the man who has to do with pipes, but it is
something which he soon becomes accustomed to. From the table
it will be seen that there is a break in the gradual increase of
thickness in pipe, occurring at the 15-inch size; the thickness of
the 15-inch, 16-inch and 17-inch being the same as the 6-inch,
7-inch and 8-inch, nearly. However, as the smith will probably
have a very limited acquaintance with these sizes of pipes, the
discrepancy will not worry him in the least.
SIZE OF PIPES.
The columns in the table which give the length of pipe neces-
sary to contain one square foot of surface are very valuable when
calculating pipes for heating purposes. So, too, are the columns
giving the length of pipe containing one cubic foot and the column
of weights.
It will be noted that pipes are threaded in a peculiar manner
and that only five pitches are used. This makes the matter of pipe
threading in the lathe a very simple matter, for of the pipes
likely to be threaded in the lathe only the sizes taking 11, 5 and 8
threads to the inch are likely to be called for. The smaller pipes
are usually threaded with a die, as are some of the larger pipes,
but the lathe is very often used for threading pipes of 2 inch and
upward in diameter.
Obviously, the first thing to do when a pipe has to be threaded
in the lathe is to get the pipe into the lathe in such a manner
that it can be cut off, if necessary, and threaded when of the
right length. If only a short piece of pipe is to be handled then
may be placed between centers, the tailstock set over for the
required taper and the threading proceeded with in the usual
But it is ten chances to one that the piece of pipe is
longer than can be put between centers, even if it is not fully as
long as the lathe bed itself.
it
manner.
SPECIAL PIPE TAIL-CENTERS.
A piece of pipe may best be held to the lathe spindle by
catching one end of the pipe in a chuck, the other end being
supported by the tail-center or by a steady rest. If a tail-center is
to be used on large pipe a special form should be used, something
a

THE SCREW-CUTTING LATHE.
153
as shown by Figs. 89 and 90. In Fig. 89, a tail-center is shown
which is made in two pieces.
The main portion, D, is fitted to the tail spindle in the usual
manner, but instead of being pointed at A the protecting part is
с
D
Fig. 89-Shell Pipe Center.
made parallel in the form of a bearing, upon which revolves the
center portion of the tool, B. A shoulder, C, takes the thrust of
the work and prevents the center, B, from slipping down the
shank D), which is, as stated, fitted into the tail spindle. That por-
tion of the center between A and B is lubricated, so that the pipe,
instead of turning upon the shell, B, carries that appliance with
it and revolves on the lubricated portion instead of in the contact
between pipe and shell B. This insures very smooth and steady
running, making it unnecessary, as often is the case when a solid
center is used, of reaming out the inside corner of the pipe so that
it could run true on the center.
When very large pipes are to be threaded another shell center
Fig. 90-Extra Shell for Very Large Pipes.
may be provided, as shown by Fig. 90. This fits the same shank
as is shown by Fig. 89 and interchanges simply by removing one
and slipping the other in place. Both these shells may be made
of cast iron or of any material which comes to hand. An old
water wheel step furnished material for a shell to accommodate
pipes between two and six inches in diameter when the writer
happened to be looking for stock for a pipe center. A hole should

154
THE SCREW-CUTTING LATHE.
be drilled in the dead center, D, Fig. 89, for oil. This hole can
be drilled through A, and another hole to meet it drilled through
C, the hole in A being plugged at its outer end and one or two
other holes drilled to the circumference of A, crosswise through
the longitudinal hole, so that oil can find ready access to all parts
of the bearing between A and B.
CUTTING OFF AND CHUCKING.
For cutting off steam pipe use an ordinary cutting-off tool,
from 14 to 14 inch wide, according to the thickness of pipe to be
cut. When the tool is nearly through the wall of the pipe great
care should be taken to prevent the tool from catching in the cut
portion of the pipe. If the tool be allowed to catch there is great
danger that the pipe will be torn out of the lathe, to the probable
damage of the lathe tools and perhaps the lathe itself. When the
tool begins to break through the pipe run the belt almost off the
pulley, using the belt shipper for that purpose, driving the lathe
very lightly, so lightly, in fact, that if the tool breaks through
it will slip the belt and stop the lathe, thus preventing the possible
breakage of tool or lathe.
Having cut off the pipe to the required length, the next step
is to mount the piece to be cut in the lathe in such a manner that
the slide-rest can be brought to the portion which is to be threaded.
If the pipe is less in length than the bed of the lathe this can easily
be done, although with a very long pipe it will be necessary to
remove the tail-stock entirely and move the slide-rest down to its
place. But when a piece of pipe must be threaded which is longer
than the entire lathe, then special rigging must be used, which
will be described in a later paragraph.
The face-plate chuck and the steady-rest form about the
best mount for a bit of pipe in the lathe, and it will be considered
that this form of drive has been applied to the pipe in question
and that the steady-rest has been set within two inches of the
thread to be cut, say three inches from the end of the pipe. The
next step is to taper the pipe as required for the thread. The
standard taper of all water, steam and gas pipes is 34 inch to the
foot.
When the tail-center is used the tail-stock may be set for-
ward to give the desired taper, but this is not possible with the
steady-rest, or with a pipe gripped in a face-plate chuck. It is

THE SCREW-CUTTING LATHE.
155
necessary to turn the taper by the eye, which can be very closely
done after a little practice. But the first few times it will be
.
well to use a pair of callipers to get the proper taper. Three-
fourths of an inch to the foot means about .0781 inch to a thread
11/4 inches long, or about 5-64 inch taper. As this amount is what
the pipe thread should taper in 1/4 inches, it is only necessary to
set the callipers to the outside diameter of the pipe, as taken from
the table, then screw up the instrument 5-64 inch and turn the
end of the pipe to that diameter as given by the callipers. Then
it will only be necessary to start a cut 174 inches, or less, accord-
ing to the diameter of the pipe, back from the end, and turn
as good a taper as the eye will permit, right down to the diameter
already cut on the extreme end of the pipe.
When the end of the pipe is thus prepared it is very easy
to cut the thread, as it will only be necessary to turn away at the
thread until it becomes full at the very end of the pipe. Then, if
the taper has been well made, the thread will have the same incli-
nation, which will be the taper desired to allow the pipe threads
to enter each other easily.
CUTTING A TAPER THREAD.
To make the tool cut an even thread along the entire length
of the tapered portion of the pipe is the next problem for the
smith to solve. Like many other problems, it is a very easy one to
solve when the right method is used. Assume that the pitch of
the cross-feed screw is eight threads to the inch. Then it is evi-
dent that one turn of the screw will advance the tool 1/8 inch.
The taper of the pipe thread is about 5-64 inch, or 27/2 sixty-
fourths on each side of the pipe. This is the amount the thread
tool must be advanced in order to cut the taper required. One-
eighth inch equals 8-64 inch, the advance of the tool to each turn
of the cross-feed screw, hence to advance the tool the required
amount the cross-feed screw must be turned 27/2 eighths of a turn,
or a little less than 5-16 of a revolution.
When the thread to be cut on the pipe is No. 8, as it is
on large sizes of pipes, the work must make about 10 revolutions
while the tool is traveling from one end of the thread to the
other. To cut a taper pipe thread with great exactness divide
the circumference of the cross-feed hand wheel into 32 equal
spaces. If there is no wheel, only a lever with crank and balance
a

156
THE SCREW-CUTTING LATHE.
ball, get out a disc of brass, tin or some other sheet metal and
make it to slip over the nut which holds the handle on the cross-
feed screw. Divide the circumference of the disc into 32 equal
spaces, then when cutting the thread it is necessary to advance the
cross-feed screw one of the spaces at each revolution of the pipe
which is being cut with No. 8 thread. If other threads are to
be cut a differently divided circle must be used on the cross-
feed screw.
For instance, should it be necessary to cut a No. 111/2 thread,
the cross-feed disc must be divided into that number of spaces
which will permit the disc to be turned the same fraction of
a revolution—2/2 inches-while the pipe is being revolved about
14 4-10 times—it requires that number of threads of 11/2 pitch to
make 1/4 inches of thread. Therefore the disc should be divided
into 56 (and a fraction) equal spaces and one of these spaces
turned ahead on the cross-feed screw at each turn of the pipe.
But as it is not always convenient to make two discs the 32 spaced
one may be used, one-half a space being advanced at each revo-
lution of the pipe. The difference is so slight that the error will
never be noticed in the completed thread.
TAPER-THREAD DIAL.
After the workman has cut pipe threads for some time he
will be able to do without the graduated disc and run the cross-
feed screw in by guess, and he can come very near to making a
perfect thread, too. Still, the graduated disc on the cross-feed
screw should be used by beginners, and by skilled mechanics
when very accurate threads are required. The same method
may be employed when it is necessary to cut bolt threads on a
taper cylinder, or to turn tapers, as well.
The manner in which the dial is made and operated may be
perhaps better understood by reference to Fig. 91. The cross-
feed handle, A A, has fitted to its nut the brass plate B, and this
plate in turn carries the dovetail circular clip C, which holds the
pointer D. The circular edge of plate B is graduated, being
divided into 32 equal portions as shown. By means of the pointer
D any desired graduation may be indicated, as in the illustration;
the pointer is shown at space 1.
It is very easy when the tool is cutting to turn the cross-feed
handle one division on the brass plate at each revolution of the

THE SCREW-CUTTING LATHE.
157
pipe, and this will give the exact taper necessary to a per-
fect thread. While the tool is chasing along the length of the
thread, being advanced one space each revolution, the lathe man
has time to get ready for the next succeeding cut. It is always
A
B
Fig. 91-Taper Thread Dial.
necessary to draw back the thread tool while running back the
lathe carriage for another cut. The tool must be thus run back
to prevent the lost motion in the lathe connections from letting
the tool lag behind just enough to tear the thread during the re-
turn of the cutting tool by a reverse movement of the lathe.
During the progress of the cut the lathe man should move
the index D enough to bring it to the left just the depth of the
cut taken each time. Thus, if it be found that the depth of cut
taken each time the tool travels along the pipe is equal to four
spaces movement of the dial and hand wheel then during the
progress of the cut, in addition to revolving the cross-feed screw
one space each revolution, the pointer must be moved to the left
four spaces and at the beginning of the next cut it must be
brought uppermost when the screw is advanced again after the
slide-rest has been run to the beginning of the thread.
That is, the lathe man runs the tool toward the work at the
starting end of the thread and stops at the beginning of each

158
THE SCREW-CUTTING LATHE.
cut with the pointer uppermost. Then he sets the pointer four or
more spaces to the left, for the register of the next cut, and starts
the lathe, advancing the cross-feed screw one space at each revo-
lution of the pipe until the end of the screw is reached, when he
reverses the lathe, gives the cross-feed screw two quick revolutions
backward to bring the tool clear of the thread, then reverses the
motion of the cross-feed screw again when the lathe carriage
reaches the commencement of the thread and has been put back to
the forward or cutting motion again. The expert workman soon
gets so that he can make the several movements without stopping
the lathe, except for the two reverse motions necessary, and at
the beginning of each cut the dial on the cross-feed screw is
brought to a vertical position at the instant the tool reaches the
beginning of the cut. A very fine and accurate job of taper turn-
ing can be done in exactly the same manner, but by using a suit-
able tool instead of the thread tool above mentioned.
THREADING PIPES LONGER THAN THE LATHE.
The arrangement for cutting off and threading a short pipe
which can be held between centers or in chuck and steady-rest
will not answer when a pipe much longer than the lathe must be
cut off and threaded. This is a job to make the machinist smith
open his eyes when it is asked of him, but the problem is not a
hard one. It only requires a little rigging up to be successfully
accomplished.
Say that a length of six-inch pipe was dumped in front
of a ten-foot lathe with the request that twelve feet of that pipe
be cut off the length and threaded. To do this remove the tail-
stock from the lathe and set up the steady-rest about two feet
from the face-plate, but put the slide-rest between the face-plate
and the steady-rest. Put one end of the pipe in the rest, letting
the point to be cut off overhang the rest toward the face-plate
about three or four inches. If only a short piece has to be cut
off it may be well to make two jobs of the work, catching the
pipe in a chuck, cutting off as described in a previous paragraph,
and afterward chucking the pipe as hereinafter described, with
the end to be threaded overhanging the steady-rest three or four
inches on the side next to the face-plate.
Next rig a bearing for the extreme end of the pipe. A scant-
ling set on end between floor and ceiling, with a bit of iron

THE SCREW-CUTTING LATHE.
159
clamped on by means of a handscrew, is all that will be
required. Failing the handscrew, nail a couple of bits of
hardwood to the scantling, oil the place where the pipe revolves
and go ahead with the pipe cutting. Another way to hold a
pipe in this manner is to set up the scantling close beyond the end
of the pipe. Bore a hole in the scantling, press the shank of the
pipe center into the hole, slip the pipe over and against the pipe
center, and the outboard bearing is all rigged, and it only re-
mains to rig up some way to drive the pipe, the other end of
which is a foot or two from the face-plate and fast in the steady-
rest.
INTERNAL PIPE DRIVE.
Fig. 92 gives an idea of one of the many ways in which
internal driving of the pipe may be accomplished. The pipe is
C
0
E
A
H
ED
с
Fig. 92—Threading Long Pipes in a Short Lathe.
shown at A, the scantling with pipe center inserted appears at B,
while the jaws of the steady-rest appear at C C, the body of the
steady-rest and the slide-rest having been omitted from the
drawing for the sake of clearness. Two pieces of flat bar iron,
.
D D, are inserted in the end of the pipe as shown by the engraving
and a block or a bit of iron-a nut, for instance—is slipped
between the bars at E to act as a fulcrum in such a manner that
when the ends of the bars next to the face-plate are pressed to-
gether the ends inside the pipe are pressed outward against the
inside of the pipe, thereby obtaining such a grip against the pipe
when the bars are rotated by the face-plate the pipe is carried
with the bars, thereby effecting the driving of the pipe for pur-
pose of thread cutting.
The next problem is to attach the ends of the lever bars to the
lathe spindle in such a manner that they may revolve the pipe
when the spindle is driven by belt. To this end the round iron
F is bent to pass through the arms of a small face-plate, the rod
being secured to the arms of the face-plate by means of nuts

160
THE SCREW-CUTTING LATHE.
and washers on the inside and outside of both the arms through
which the rods pass. To secure a properly rigid connection
between the iron bars and the round iron F a bolt is placed
through both bars as shown at H, inside the round U-bolt F,
thereby clamping the bars rigidly to the face-plate, also to the
pipe A, which must therefore always revolve in unison with the
face-plate. The pipe is also held rigidly endwise by the same
force which holds the pipe firmly to the face-plate, hence there is
no danger that the pipe can slip sidewise, as when on centers
and held by a dog, neither can it slide endwise, no matter how
flimsy may be the support of the tail-center B.
In order to make as rigid a connection as possible with the
face-plate the bars D D should be as short and as stout as possible.
There is no reason why the steady-rest should not be placed as
close to the face-plate as possible and leave room for the slide-
rest to traverse the distance required for the length of thread
on the pipe. It is evident that when the bars D D are quite long
there will be more or less spring to them, thereby allowing the
pipe to rotate considerably under the pressure of the thread tool,
but if the bars be made very short and as wide and thick as can be
gotten into the end of the pipe, then there is little danger that
the bars will spring enough to cause any trouble in the thread
cutting.
When actually cutting the thread on a piece of pipe do not
try to cut with a pointed tool. Cut the thread to nearly the
finished size with at least 1-32 inch ground off the point of the tool.
A thread tool thus squared off on the end will stand sharp much
longer than if the attempt be made to cut the thread with a
fine sharp point on the tool. After the thread is cut down almost
to size then grind the tool to the correct shape for a finishing cut
and run it lightly over the thread two or three times to clean out
the bottom of the thread and a very nice cut will be the result.
a
THE END.

INDEX.
А
Allowance for shrink....
134
Auger, pod..
102
Absorbed in water cut, heat..
50
Auger shank in spindle chuck. .102
Accident to lathe gears..
31 Automobile crank shafts..
..111
Accurate and straight boring, tools for 77 Avoid fractional dimensions.
139
Accuracy, to obtain extreme.
56 Avoid square corners in castings....141
Accurate centering of chucking. 72 Awl-hole, end lacing with..
18
Accurate holes, drilling of.... .116
Accurate drilling or counter-sinking. .117
B
Accurate taper turning.
.158
Acquire the sketch habit.
.110 Backing pulley
14
Action of adjusting wedge.
36 Bad and good calipering.
94
Action, wedge, of lathe tool..
49
Back gear and its use, the.
34
Actual and nominal diameter of pipes. 151 Back gear, and lathe step cones. 45
Added with profit, lathe tools which Backing carriage by hand or by belt. 15
may be..
..107 Back rest, construction of a.
33
Adhesion, belt
146-147 Bad (and good) crank forgings. .111
Adjusting lathe attachments.. ..108 Bad centering work
28
Adjusting screws and bolts on face Bad chick practice
71
plates
85 Bad, if cheap, engineering.
.111
Adjusting screws, holding power of.. 85 Badly turned or conical pulleys. 21
Adjusting spindle bearings..
22 Bar, boring improved steel collar for. 89
Adjusting stud and gears for screw Bar, boring, collar for.
88
cutting
61 Bar, boring, its use.
75
Adjusting lathe centers.
22 Bar, boring, tool adjustment for.. 88
Adjusting wedge, action of.
36 Bar, boring, in cylinder, method of
Adjustments, cylinder turning, making
centering
93
rough and fine..
93 Bearings, adjusting spindle.
22
Adjustment marks of tail center.. 24 Bearing, artificial, for steady rest. 33
Adjustment of a tool, method of. 35 Bearings, method of taking wear in.. 22
Adjustment of boring bar tool. 88 Bearings or centers, grinding on. 56
Adjustment of carriage clips...
26
Bearings, worn spindle..
9
Adjustment of chuck by check-nuts.. 85 Bed, heavy lathe
11
Adjustment of lathe spindle..
21 Bed, leveling lathe
13
Adjustment of spindle check-nut. 22 Bed of lathe, worn.
9
Adjustment of tail center...
24 Bed, setting the lathe.
13
Adjustment of tail spindle..
9 Bed, tests for wear in the.
9
Adjustment of tool by means of collar Beeswax, putty and leather fillets for
and wedge..
36
pattern corners
Aligning shafting
18 Beginning and ending belt lacing. 18
Alignment of lathe centers, testing. 23
Best belts are endless.
148
Allowance for wear in grinding a tool 35 Best side of a casting.
.143
Allowance, making, to the foot of belt. 15 Best size of lathe to purchase. 7
Ancient index plate
124 Binder or tightener for belts.
148
Angle of centers.
24 Belt adhesion
.147
Annealing lathe centers.
25 Belt, allowance to the foot of.
15
Anvil and chalk straightening.
31 Belt and pulley paradox..
147
Anvil, the....
36 Belt and pulley surface contact. .147
Applying leather fillets.
142 Belt and pulley widths.
21
Approximating speed of circular saw.136 Belt, arc of contact of
148
Apron and slide rest.
58 Belt, backing of lathe carriage.
15
Apron, wear in...
10
Belt binder or tightener.
.148
Apparatus necessary for milling. .120 Belt box..
15
Are of contact of belts...
.148 Belt, crooked places in.
21
Arkansas slips for wood turning tools. 101 Belt, defect of the rubber.
150
Around cylinder, pouring plaster.... 96 Belts, determining the proper length of. 15
Arrangement of compound change Belts, endless, the best.
148
gears
62 Belt fastenings, sizes of.
.149
Arrangement of modern box gear.. 63 Belts, fitting and cutting.
15
Artificial bearing for steady rest. 33 Belt guides, board..
21
Attachments, and jigs, labor saving..106 Belt hooks, Bristol.
148
Attachments for a lathe, a crank on..119 Belt, knack of shifting.
22
Attachments for milling in the lathe. 123 Belt lacings....
.149
Attachments for planing in the lathe. . 107 Belt lacing, beginning and ending. 18
Attachments, lathe, adjusting of... .108 Belt lacing, strands, crossing.
18
Attachments, lathe, doubtful value of. 108 Belts, good method of lacing.
16
Attachment, taper, for the lathe. ....106 Belts, leather and rubber..
.150
.142
(i)

ii
INDEX.
...146
..148
.140
.150
16
15
Belts, length of....
Belt, power of a..
Belt power tables and calculations...144
Belt running on edge of pulley.. 21
Belt speed for twenty feet, per minute 54
Belt splicing and lacing.
.148
Belt, squaring ends of..
.148
Belt splice, calculating strength of.. 17
Belts, pulleys and shafts..
144
Belts, punching holes and lacing. 15
Belts, quality of..
.149
Belts, stretch of.
Belt studs, Blake.
.148
Belts required for lathe.
15
Belts, slip of.....
.146
Belts, types of cotton.
.149
Belts, tracking of.
21
Belt tools, box for..
Belt, what to buy.
Belts which give trouble.
с
Calcined plaster, chucking obstinate
pieces with...
86
Calculating change gears.
59
Calculating dimensions of pulley
flanges
Calculating length of pulley hubs. ...140
Calculating pulley diameters...
14
Calculating strength of belt splice.. 17
Calculations for set-screws..
.137
Calculations of horse power.
.145
Caliper at angle to which cylinder is
bolted
93
Calipering, directions for.
94
Calipering, good and bad..
94
Calipering vertically and horizontally. 93
Caliper readings, incorrect..
94
Caliper vertical and horizontal.. 93
Cam and split nut...
11
Capacity, earning, of a lathe, enlarg-
ing the
119
Card clothing..
52
Carriage clips, adjustment of.... 26
Carriage for lathe, thread clamp for.. 66
Carriage, lathe, backing by hand or
belts
Carriage, lathe, clamping of..
30
Carriage running back by reversing the
lathe
15
Carriage, special milling, for the lathe. 122
Casting, designing a.
..130
Casting, the best side of a.
..143
Castings, avoid square corners in....141
Castings broken by poor designing...135
Castings, cooling, strains caused by..135
Castings, weak...
.133
Cast iron and brass turning, tools for 39
Cast iron cones, plain...
12
Cast iron, cutting speed for.
45
Cast iron cutting tools...
37
Cast iron, roughing...
48
Cast iron, twenty ft., per minute. 45
Cast iron wall bracket.
131
Catching threads....
67
Catching threads, method of.
68
Caution in clamping with lead screw. 30
Centering a cylinder.
92
Centering boring bar in cylinder,
method of....
92
Centering, chalk method..
28
Centering cylinder by counter bore. 90
Centering, incorrect and correct... 29
Centering indicator..
72
Centering small work, with wax. 87
Centering work, bad..
28
Centering work in the screw cutting
28
Center, adjustment of tail...
24
Center, cup, for wood...
104
Center drill, proper size of.
29
Center driving rod.
81
Center gage...
25
Center grinding, gage for.
24
Center lines, making.
.113
Center, adjustment marks of
24
Center, removing before using face
plate
80
Centers, angle of.
24
Centers, chipping
29
Centers, crank, drilling and counter-
sinking in jigs.
116
Centers, crank, drilling of.
Centers, distance between.
8
Centers, drilling of.
Centers, hardening.
25
Centers, hardening, grinding and tru-
.149
.144
Bent and straight thread tools.
39
Blake belt studs....
148
Blacksmithing, expansive.
.130
Blacksmithing, machine.
.127
Blocking up head and tail stocks.. 8
Blocks, parallel, graduated length. 83
Board belt guides
21
Bore, counter countering cylinder by. 90
Boiling point of soda water...
50
Bolt, eye, design for an..
.128
Bolting cylinder flanges, improper. 91
Bolting small work on face plate. 79
Bolts and adjusting screws for face
plate
85
Bolts and straps for pulley chucking. 83
Bolts, holding, tapped into slide rest
or lathe carriage...
92
Bolts, reversing chuck.
86
Bolts, strength of in single shear. 140
Books, reference.
132
Boring
81
Boring, accurate and straight, tools
for
77
Boring a pulley hub.
143
Boring bar collar..
88
Boring bar collar, improved steel. 89
Boring bar, chucking drill...
76
Boring bar in cylinder, method of
centering
93
Boring bar tool adjustment.
88
Boring in the lathe..
88
Boring out valve cylinders.
88
Boring pump logs.
.102
Boring, setting steady rest for.
74
Boring small cylinders..
89
Boring taper holes....
.106-107
Boring tool, clearance necessaary for. 69
Boring tools, proper setting of..... 77
Boring tools, wood, method of using..102
Bottom, grind tool from.
44
Bex, belt.
15
"Box" change gears.
62
Box. core.
141
Box for belt tools...
15, 16
Box, gear, modern arrangement.
63
Bracket, wall, cast iron.
.131
Bracket, wall making a.
.131
Brass and cast iron turning, tools for. 39
Brass, cutting speed for...
45
Brass cutting tools..
37
Bright work, marking on.
113
Bristol belt hooks.
148
Broken castings by poor designing...135
Built-up pulley, a.
.139
Buffing and polishing.
57
Buffing wheels.
57
Bushed with steel, holes in jigs. 98
Buy a power hack saw
.108
Buy a showel or clean the lathe. 59
ing
Center, hollow, in tool post of lathe. .102
lathe
116
29
24

INDEX.
iii
Centers, putting in line.
22
Centers, lathe test for truth of. 25
Centers, lathe, testing alignment of... 23
Centers of lathe, grinding.
25
Centers of lathe, springing of, when
hardened
.. 25
Centers, or in bearings, grinding on. 56
Centers, reaming.
29
Center, shell for pipe.
153
Centers, swing between
8
Center, tail, moving the
24
Center, tail, removing a
26
Center test necessary frequently. 24
Centers, truing.
29
Centers, tail, special for pipe... .152
Center, turning.
25
Chalk and anvil, method of straight-
ening
31
Chalk and clay, polishing with.
51
Chalking files...
52
Chalk, method of centering.
28
Chalking rough surfaces.
..114
Change gears..
59
Change gears, arrangement of com-
pound
62
Change gears, “Box'
62
Change gears, calculating.
59
Change gears, compound and simple.. 60
Change gears for cutting left hand
threads
61
Change gears for cutting right hand
thread
60
Changing speed of shafting.
.137
Cheap but bad engineering.
..111
Check-nut, adjustment of spindle.. 22
Check-nuts, fine adjustment of chuck
by
85
Chipping centers
29
Chipping wrought iron, use of oil
when
49
Chips, cutting continuous.
44
Chips, rough and lumpy..
48
Chuck and lathe, geometrical.
58
Chuck and steady rest, use of the. 70
Chuck, bad practise.
71
Chuck bolts reversing.
86
Chuck drill cutters..
77
Chuck drill rigging.
76
Chuck, fine adjustment of, by check-
nuts
85
Chuck, face plate, using a.
Chucking
81
Chucking and cutting off pipe in the
lathe ..
.154
Chucking a heavy pulley
84
Chucking a pulley.
82
Chucking irregular work.
86
Chucking obstinate pieces with calcined
plaster
86
Chucking odd shaped pieces of metal 86
Chucking, pulley, straps and bolts for 83
Chucking tool....
76
Chucking very small pieces with wax. 66
Chucking with wooden shapes....
Chucking work in the lathe.
81
Chucking work with plaster.
95
Chuck, large independent.
.85
Chuck, making a handy
84
Chucks, drill....
97
Chucks for large and small drills. 97
Chuck, screw, for lathe..
.104
Chucks, lathe and drill, interchange-
able
97
Chuck spindle, auger shank in. .102
Chuck, substitute for a large.
84
Chucks vs. face-plates...
84
Chuck, truing up work with an inde-
pendent ..
73
Circles, lathe speed.
Circular saw, approximating speed of. 136
Circular saw, hammering a.
.136
Circular saw, speeding a..
.136
Circular saws, wandering" of. .137
Clamping tail spindle....
27
Clamping the lathe carriage.
30
Clamping with the lead screw
30
Clamp, thread, for lathe carriage. 66
Clay and chalk, polishing with. 51
Clean the lathe or buy a shovel. 59
Clearance and rake of lathe tools. 37
Clearance and rake varied by tilting
tool
39
Clearance increased by grinding front
of tool ..
.. 39
Clearance necessary for a boring tool 69
Clearance of lathe tool, side.
37
Clearance, or bottom rake..
37
Clips, carriage, adjustment of.
26
Clogging of the reamer..
78
Closer forging than lathe working. .111
Cloth, emery, and its uses..
53
Clothing, card..
..52
Clutch, friction.
11
Collar and wedge for tool adjustment 36
Cotton belts, types of....
..149
Collar for boring bar..
88
Collar, making a pattern for. ..105
Collar pattern, turning a.
..105
Collar, tool-post....
36
Collar and wedge, adjustment of tool
by means of..
36
Collar, improved steel boring bar..
89
Common forms of lathe tools...
38
Compound and simple change gears.. 60
Compound change gears, arrangement
of
62
Compound gearing for screw cutting.. 62
Condition of spindle....
9
Condition of tool post set screw. 35
Cone friction..
12
Cone pulley and its use.
..34
Cone, headstock....
11
Cones and back gear.
45
Ccnes, cast iron, plain.
12
Cones of head spindle
9
Cenical pulleys, badly turned
21
Constructing a surface gage.
115
Construction of headstock and slide
rest
21
Construction of polishing wheels. 57
Construction of steady rest.
32
Contact, arc of, of belt...
..148
Contact, surface, of belt and pulley..147
Counter-bore, centering cylinder by... 90
Countersinking crank centers in jigs. 116
Countershaft, overhead.
11
Countershaft, Speed of.
14
Countershaft, the lathe.
14
Countersinking, accurate method of.. 118
Core box..
141
Cored holes.
141
Core prints...
.141
Corners of patterns, fillets for.. .142
Corners on drawings and patterns.. 142
Corners on patterns..
..141
Correct and incorrect centering.
29
Corners, pattern, method of filling. 142
Corrections for screw, table of.. 58
Cooling a lathe tool...
50
Cooling castings, strains caused by...135
Copper hammer, soft....
25
Copper sulphate solution for marking
on bright work...
..113
Crank centers, drilling.
.116
Crank centers, countersinking of, in
jigs
..116
Crank forgings, good and bad. ..111
Crank shaft, jig for turning a. ..112
85
86
47

iv
INDEX.
..113
.
26
50
46
Crank-shaft jig, laying out a...
Crank shaft, laying out a... ..114
Crank shaft, quarter turn, making a. 110
Crank-shafts for automobiles.
.111
Crank-shaft jigs...
..112
Crank-shaft wrist-pin, turning a.....118
Crank steady pieces..
.118
Cranky on the subject of lathe attach-
ments
.119
Cross-feed jibs, setting of.
Cross-feed screw, lost motion in.. 10
Crossing of belt lacing strands.. 18
Crooked places in belt..
21
Cost of diamond tool..
56
Cost of pulleys and belts
.145
Cost of special machines and tools...120
Continuous clips, cutting.
44
Cotton waste, plugging spindle with.. 81
“Cut and try” work...
.110
Cut, water, finishing, theory of. 49
Cut, water, heat absorbed in.
50
Cup center for wood.
104
Cupola, small, for melting iron. 135
Cuts, finishing and roughing.
48
Cut, pulling and pushing.
40
Cuts, scraping, more.
105
Cuts second and finishing.
49
Cuts, setting tool for finishing. 49
Cuts, soda water for finishing:
Cuts, pipe thread, roughing and finish-
ing
Cylinder, pouring plaster around.... 96
Cylinders, boring small
89
Cylinders, boring out valve.
89
Cylinder turning adjustments, making
rough and fine
93
Cylinder with Plaster of Paris, mount-
ing a...
92
Cylindrical form lost by filing. 51
D
Damage to rod and screw feeds... 31
Danger of lathe grinding.
57
Deep drilled center holes.
29
Defect of the rubber belt.
150
Depth of cut...
44
Designing a casting
.130
Designing an eye bolt..
.128
Designing, poor castings broken by..135
Design for fillets, nature's... .142
Department store, mechanical. .127
Destroys the lathe, tool-post grinding. 57
Determining the proper length of belts. 15
Dial, taper thread..
.156
Diamond tool, cost of.
56
Diamond-tool for dressing emery
wheel
56
Diamond tool, selecting a.
56
Diameter and surface, emery grind-
ing, for
56
Diameter, nominal and actual, of pipes.151
Diameter, velocity ..
47
Diameters, calculations of pulley. 14
Diameters, formula for pulley.. 14
Diameters of work giving twenty feet
per minute
Dimensions, avoid fractional
.139
Dimensions of pulley flanges, calculat-
ing the
140
Dimensions of steam, water and gas
pipes
Directions for calipering
94
Dirty file, good work is impossible
with a
52
Distance between centers.
8
Distress of lathe tool....
48
Dividing head ..
125
Dividing head, a modern.
125
Dividing head, rudimentary
121
Dividing head for milling machine.... .121
Dog, lathe, for wood turning.
Dog, lathe making a star dog.. .103
Dog, tieing up the.
66
Dog, wing, lathe
103
Do not mix your machines.
.119
Double-line cuts..
43
Doubtful value of lathe attachments..108
Dressing emery wheel, diamond tool
for
56
Dressing emery wheels frequently.
Draw filing a pulley
.151
.102
56
.100
Cuts, taking thick
44
Cuts, taking roughing and finishing for
thread.
66
Cuts, water.
49
Cut, taking a roughing.
49
Cutting a taper pipe thread.
155
Cutting and fitting belts.
15
Cutters, chuck drill..
77
Cutting a screw, compound gearing for. 62
Cutting continuous chips..
44
Cutting edge of tool, position of.. 35
Cutting gears and polishing in the lathe.107
Cutting internal threads.
77
Cutting left hand threads, change
gears for
61
Cutting off and chucking pipe in the
lathe
. 154
Cutting off tool.
39
Cut, tool setting for roughing.. 48
Cutting right hand threads, change
gears for..
60
Cutting speed for brass.
45
Cutting screws
58
Cutting speed for brass
45
Cutting speed for cast iron.
45
Cutting speed for steel
45
Cutting speeds, graphic, representation
of
46
Cutting speed for wrought iron. 45
Cutting tools, shape of thread.
63
Cutting tools, brass
37
Cutting tools, cast iron.
37
Cutting tool for wood, grinding a....101
Cutting tool, proper condition of.... 35
Cutting up iron in the lath..
108
Cutting wood, slide rest tool for.....100
Cutting wood when turning. ..100
Cylinder, mounting by the flanges. ... 91
Cylinder, caliper at angle to which it
is bolted.
93
Cylinder, centering a.....
92
Cylinder, centering, by counter bore.. 90
Cylinder flanges, improper bolting of. 91
Cylinder in the lathe, mounting a... 89
Cylinder, method of centering boring
bar in
93
Cylinder mounted on slide rest.
91
Cylinder on face plate, mounting a.. 90
.147
Draft in patterns
.133
Draft, or taper of patterns
.147
Drawings and patterns, corners on. . 142
Drawings, making
Drawings, pattern, of pulley hub....137
Drawn by fast grinding, temper. ... 48
Drill and lathe chucks, interchangeable 97
Drill cutters, chuck...
77
Drilled center holes, deep.
29
Drill for center, proper size of.
29
Drilling ..
81
Drilling accurate holes
..116
Drilling and countersinking crank cen-
ters in jigs.
.116
Drilling centers
29
Drill chucks
97
Drilling crank centers...
.110
Drilling in a lathe is poor practise. . . 96
....127

INDEX.
V
46
Drilling or countersinking, accurate
method of
..117
Drilling or turning glass
50
Drill or lathe, reaming spindle of. 97
Drill press jigs
98
Drill, power .
96
Drill rigging, chuck
76
Drills, chucks for large and small. 97
Drill, tapping
88
Driving face plate.
79
Driving rod, center
81
Drive, internal pipe.
.159
Drive pulley, special, for wood turning. 99
Drum overhead, for grinding
54
Dull lathe tools, never work with... 44
51
E
Earning capacity of a lathe, enlarging
the
.119
Easy adjustment of tool post
35
Economy, special tools for.
96
Edge of pulley, running of belt on 21
Edge of tool, cutting position of. 35
Emery cloth and its use..
53
Emery grinding for diameter and sur-
face
56
Emery wheel dressing necessary fre-
quently
... 56
Emery wheel, diamond tool for dress-
ing
56
Emery wheels, grinding with
54
Emery wheels, keeping in order.
55
Emery wheel, metal wasted on. 48
Emery wheel, spoiling tools on.
48
Emery wheel traversing past the work. 55
Emery set with tallow..
57
Emery wheel, selecting an
55
Ending belt lacing
18
Endless belts the best..
148
Engineering, cheap but bad.
.111
End lacing with awl-hole
18
Error in a good screw..
58
Error, limit of in turning.
32
Ends of belt, squaring
148
Excellent wire lacing
18
Extension of lathe-bed..
8
Expensive use of thread tool.
43
Extreme accuracy, to obtain
56
Expansive blacksmithing
130
Extra shell for very large pipe.. .153
Eye-bolt, designing an ...
..128
Feed screw, cross, lost motion in 10
Feed, reversing when wood turning...101
Feeds, rod and screw, damage to 31
Feed, screw and rod in gear at same
time
30
Feet a minute, diameter of work giv-
ing twenty
Feet per minute for cast iron, twenty. 45
Figuring belt speed for twenty feet a
minute.
46
File, good work impossible with a dirty. 52
File handles
52
File, how to hold a
52
File, picking a
53
File, proper movement of
52
Files, chalking
52
File scratches on the work.
52
Files, removing grease from
52
File, selection and use of
51
File teeth, particles of metal in.
52
Files, treatment of new
52
Filing, cylindrical form lost by
51
Filing, draw, a pulley
.147
Filing flat places
Filing, speed of work for
51
Filing to remove tool marks
51
Filing work in the lathe
50
Filing work to be polished
51
Fillets, method of applying
.142
Fillets, nature's design for
.142
Filling pattern corners, method of. 142
Fine adjustment of chuck by check-
nuts
85
Fine finish, obtaining
49
Finishing and roughing cuts
48
Finishing and roughing-out jigs. .117
Finishing and roughing pipe thread
cuts
.160
Finishing and roughing thread cuts,
taking
66
Finishing and second cuts
49
Finishing cuts, setting tool for
49
Finishing cuts, soda water for
50
Finish, obtaining fine
49
Finishing or polishing irregular sur-
faces
57
Finished surface, turning to obtain. 44
Finishing tool, water
39
Finish, water cut, theory of
49
First piece of work, the
12
Fitting belts
15
Flanged pulley hubs
.137
Flanges, improper bolting of cylinder. 91
Flanges, pulley, calculating dimensions
...140
Flanges, mounting cylinder by the.. 91
Flange, thickness of, for a pulley .140
Flat places, filing
51
Forge or foundry, remove metal at. 44
Forging closer than lathe work..
Forging for quarter-turn crank ..111
Forgings for a quarter-turn crank... 111
Fcrgings, good and bad for a crank. .111
Form, cylindrical, lost by filing.. 51
Formula for pulley diameters.
14
Forms of lathe tools, common.
38
Form of simple lathe tools..
38
Foundry or forge, remove metal at.. 44
Fractional dimensions, , avoid if pos-
sible
.139
Frequent emery wheel dressing neces-
sary
56
Frequent tests of centers necessary. 24
Friction clutch.
11
Friction, cone.
12
Front bearing cones, straight or taper. 22
Front cutting tools..
37
Front grinding of tool increases clear-
ance
39
F.
of
0 0
...111
Face plate and work, removing wax
from
87
Face plate, bolting small work on... 70
Face plate bolts and adjusting screws. 85
Face plate chuck, using a
85
Faced with leather, wheels
57
Face plate, large
80
Face plate, mounting a cylinder on a. 90
Face plate of lathe, supporting an ugly
job on
96
Face plate pattern work
104
Face plate, removing center before us-
ing
80
Face plate, screwing, on spindle too
tight
80
Face plate, solid
79
Face plate, small slotted
Face plate, the
79
Factor of safety
129
Fancy lathe
8
Fastenings, for belts, sizes of. 149
Fast grinding, temper drawn by. 48
Face plates vs. chucks
84
79

vi
INDEX.
25
G
Gage, center..
25
Gage for lathe center grinding.
24
Gages, surface, two necessary.
114
Gage, surface..
115
Gage, surface, constructing a.
115
Gear, back, and lathe step cones. 45
Gear, box, modern arrangement. 63
Gearing, compound, for screw cutting. 62
Gear cutting and polishing in the
lathe
.107
Gears, arrangement of compound
change gears..
62
Gears, change, “Box”
62
Gears of lathes, accidents to.
31
Gear, use of the back..
34
Generalizing vs. specializing.
127
Geometrical lathe and chuck.
58
Gandy, rub-oil, Mount Vernon, types
of cotton belts.....
.147
Gear and stud..
60
Gears, calculating change.
59
Gears, change..
59
Gears, change, for cutting left hand
threads
61
Gears, change, for cutting right hand
threads
... 60
Gears, change, compound and simple. 60
Gas pipes, water and steam, dimen-
sions of...
....151
Getting or putting work in the lathe. 82
Glass, turning or drilling.
50
Glue, method of using.
143
Gluing up a pattern..
143
Go-ahead, pulley...
14
Good and bad calipering
94
Good and bad crank forgings.
111
Good method of lacing belts.
16
Good tool post, importance of a. 35
Good work impossible with a dirty
file
52
Graduated length, parallel blocks. . 83
Graphic representation of cutting
speeds
46
Grease, removing, from files.
52
Grinding back advance corner of tool. 42
Grinding, danger to lathe.
57
Grinding front of tool increases clear-
ance
39
Grinding hand tools..
..106
Grinding hardened rolls...
56
Grinding, hardening and truing cen-
ters
24
Grinding lathe centers.
25
Grinding lathe centers, gage for. 24
Grinding lathe tools, models for.. 38
Grinding on centers or in bearings. . 56
Grinding, overhead, drum for....
54
Grinding rig, tool-post.
54
Grinding rig, overhead, tool-post for.. 55
Grinding, steel wasted by poor.
48
Grinding surfaces with emery.
51
Grinding, temper drawn by fast. 48
Grinding tool, allowance for wear in. 35
Grinding, tool-post, destroys the lathe. 57
Grinding tool temporarily..
44
Grinding, with emery, for diameter
and surface..
56
Grinding with emery wheels.
54
Grinding wood cutting tool.
101
Grind tool from bottom..
44
Ground, when tools should be.
48
Guides for belt, made of a board..
21
Half-diamond and round-nose tools. . 39
Hammering circular saws.
.136
Hammering wire belt lacing.
18
Hammer of soft copper...
25
Hand backing of lathe carriage.
15
Handles of files...
52
Hand tools, grinding,
.106
Hand tools, two handy.
.105
Handy chuck, making a.
84
Hardened lathe centers, springing of. 25
Hardened rolls, grinding..
56
Hardening and grinding centers. 24
Hardening tail-centers.
25
Hard usage
8
Head and tail spindles, testing.
9
Head, dividing
125
Head center, soft.
Head, dividing, a modern.
.125
Head, dividing, a rudimentary .121
Head, dividing, for milling machine. . 121
Head spindle cones.
9
Headstock and slide rest, construc-
tion of...
21
Headstock, blocking up
Headstock, lathe, reverse in.
62
Headstock step cone....
11
Heat absorbed in water cut.
50
Heat between tool and work.
48
Heavy lathe bed..
11
Heavy pulley, chucking a
84
High polish on lathe work.
54
High speed lathe practise.
47
High speed work, tools for..
47
High surface velocity for wood turn-
ing
99
Hold a file, how to.
52
Holding bolts, tapped into slide rest
or lathe carriage..
..92
Holding power of adjusting screws.. 85
Holes, accurate, drilling of.
.116
Holes, boring on a taper..
Holes, cored
. 141
Holes in house-moving rolls, making
of
...101
Holes in jigs, steel bushed.
..98
Holes, properly and improperly
punched
17
Holes, punching and lacing belts.
15
Hollow lathe center in tool-post. 102
Hooks, Bristol belt....
148
Horizontal milling.
.123
Horizontal and vertical calipering. 93
Horse power calculations. .
145
House-moving rolls, making holes in. 101
How to hold a file..
52
How to use the lathe.
12
Hub of a pulley, boring a.
.143
Hub, pulley, pattern drawings of.
.137
Hubs, for flanged pulleys..
.137
Hubs, pulley, length of
82
Hubs, pulley, calculating the length
of
888HASH旺旺​红​的​8
..107
. 140
I
Impossibility of perfect turning..
32
Impossible with a dirty file, good
work is...
52
Improper and proper punch holes... 17
Improper bolting of cylinder flanges.. 91
Improperly set in tool-post, tool. 39
Importance of a good tool-post... 35
Improved steel boring bar collar. 89
Incorrect and correct centering.
29
Incorrect caliper readings....
Increases clearance, grinding front of
tool
39
Independent chuck, large.
84
94
H
Habit, sketch, acquire the.
Hack saw, power, buy a.
110
108

INDEX
vii
72
72
Independent chuck, truing up work
with an
73
Index plate
.125
Index plate, ancient..
..124
Index, using the thread.
.157
Indicator, centering...
Internal treads, centering.
Internal threads, cutting
77
Inside and outside turning tools for
slide rest wood working.......101
Inside thread tools...
39
Interchangeable lathe and drill chuck. 97
Internal pipe drive..
..159
Internal turning or boring.
69
Iron, cast, and brass turning, tools
for
39
Iron (cast) cones, plain..
12
Iron, cast, cutting speed for.
45
Iron, cast, cutting tools
37
Iron, cast, roughing...
.48
Iron, cast, wall bracket..
.131
Iron, cutting up in the lathe.
. 108
Iren, melting, small cupola for. .135
Iron, tensile strength of..
.128
Iron, twenty feet per minutes for cast. 45
Iron, use of oil
when chipping
wrought
49
Iron working lathe, turning wood in
the
99
Irregular surfaces, finishing or polish-
ing
57
Irregular work, chucking.
86
J
Jigs and attachments, labor saving..106
Jigs and tools..
96
Jigs, drilling and countersinking cen-
ters in....
Jigs for a crank shaft.
.112
Jigs for drill press..
98
Jigs for lathe work..
98
Jigs for milling in the lathe.
107
Jig for turning crank shaft..
112
Jigs, roughing out and finishing. 1.117
Jig, laying out one for a crank shaft. 113
Jigs, steel bushed holes in.
98
Job, ugly, supporting on the lathe
face plate
96
.116
K
Keeping emery wheels in order...... 55
Key note of success in machine work.119
Knack of shifting lathe belt .... 22
L
of a
| Lathe and chuck, geometrical..... 58
Lathe and drill chucks, interchange-
able
97
Lathe attachments, adjusting ..108
Lathe attachments for planing. ..107
Lathe attachments, doubtful value of. 108
Lathe-bed extension
8
Lathe-bed, heavy..
11
Lathe, how to use the.
12
Lathe, bed, setting the
13
Lathe belt, knack of shifting.
22
Lathe bed, levelling.
13
Lathe-bed, worn
9
Lathe, belts required for.
15
Lathe, best size of to purchase.
7
Lathe, boring in the...
88
Lathe carriage, clamping of..
30
Lathe carriage, thread clamp for. 66
Lathe carriage holding bolts tapped
into slide rest...
92
Lathe centers, grinding.
25
Lathe center, hollow, in tool post.. 102
Lathe centers, annealing: ..
25
Lathe centers, testing alignment of.. 23
Lathe, chucking work in the... 81
Lathe, clean the, or buy a shovel. 59
Lathe countershaft, the....
14
Lathe center,
center, springing of, when
hardened
25
Lathe dog for wood turning
.102
Lathe, cutting up iron in the .....108
Lathe, drilling in, is poor practice... 96
Lathe, enlarging the earning capacity
.119
Lathe, fancy
8
Lathe, filing work in the
50
Iathe for true centers, test of.
25
Lathe, gage for center grinding.
24
Lathe, gear cutting in the
.107
Lathe grinding, danger of
57
Lathe headstock, reverse in.
62
Lathe, iron working, turning wood in
the ....
9
Lathe, jigs for milling in the. .107
Lathe, levelling and shimming
13
Lathe, milling attachments for. .123
Lathe, milling in the
.119
Lathe, mounting a cylinder in the. .89
Lathe, mounting pipe in the.. .154
Lathe, necessary apparatus for milling
in the
Lathe or drill, reaming spindle of. 97
Lathe, polishing in the
.107
Lathe, proper speed of
44
Lathe, reaming in the..
78
Lathe, putting and getting work in
the
82
Lathe, putting work into
28
Lathe reversing, running carriage back. 67
Lathe scraping wood in the.
99
Lathe, selection of a
7
Lathe, selecting a second-hand.
8
Lathe, screw chuck
104
Lathe, screw cutting, centering work
in the
28
Lathe screw, stud and spindle. 58
Lathe, special milling carriage for. . 122
Lathe speed circles
47
Lathe, speed of work in the.
34
Lathe spindle taper, reamer for. 97
Lathe spindle, adjustment of
26
Lathe, support of
14
Lathe step cones and back gear. 45
Lathe, supporting thin metal plates in
the
86
Lathe, swing of
8
Lathe, taper attachment for..
106
Lathe, threading pipes longer than
the
.158
....120
0000
16
Lathe, cutting off and chucking pipe
in the
.154
Labor saving jigs and attachments...106
Lacing and splicing, of belts.
.149
Lacing of belt, beginning and ending. 18
Lacing belts and punching holes... 15
Lacing belts, good method of.....
Lacing, end with awl-hole..
18
Lacing, strands of belts crossing. 18
Lacing excellent wire..
18-19
Lacing with rawhide.
17
Lacings of belts..
.149
Large and small drills, chucks for. 97
Large chuck, substitute for.... 84
Large face plate...
80
Large independent chuck..
85
Lathe, accident to gears.
31

viii
INDEX.
Lathe, threading long pipes in a short. 159
Lathe, threading pipes in the..
.151
Lathe tool, cooling a.
50
Lathe tool, distress of
48
Lathe, tool-post grinding destroys the. 57
Lathe tool, side clearance
37
Lathe tools, clearance and rake of. 37
Lathe tools, common forms of
38
Lathe tools, models for grinding.
38
Lathe tools, never work with dull. 44
Lathe tools, proper setting of
39
Lathe tools, simple, form of
38
Lathe tools to be added with profit. 107
Lathe tools, use of turpentine on. 50
Lathe tools, wedge action of..
49
Lathe, turning tapers in.
24
Lathe v's, vertical wear in.
10
Lathe, what kind of?.
11
Lathe, wing, dog...
103
Lathe work, forging closer than. 111
Lathe work, high polish on... ...
54
Lathe work' jigs .
98
Lathe work, soap suds or oil for. 50
Lathe work, straightening
31
Laying out a crank shaft..
144
Laying out a crank shaft jig.
113
Lead or babbitt metal hammers.
25
Lead-screw clamping, caution in. 30
Lead screw, clamping with the... 30
Lead screw, split nut on.
59
Lead screw, tests of..
10
Leather and rubber belts.
150
Leather faced wheels
57
Leather fillets for pattern corners. .142
Leather fillets, method of applying ... 142
Left hand threads, change gears for
cutting
Length of belts
.146
Length of belts, determining the proper 15
Length of pulley hubs
82
Length of pulley hubs, calculating the.140
Levelling and shimming lathe bed... 13
Level surface for polishing, obtaining a 54
Lever and peening straightening of
shafting
31
Lines, center, making of
113
Lining up steady rests..
33
Line, putting centers in
22
Limit of error in turning
32
Limit to size of pulleys
146
Logs, boring for pump
102
Long shafting, straightening
31
Long shafts. turning
32
Lost by filing, cylindrical form 51
Lost motion in cross feed screw. 10
Lowering and raising point of tool... 36
Lumpy and rough chips
48
Making rough and fine cylinder turn-
ing adjustments
93
Making vs. manufacturing.
98
Marking bright work
.113
Marking on bright work with sulphate
of copper solution
....114
Marking rough surfaces, chalk freely. 114
Marks for adjustments of tail center. 24
Marks of tools removed by filing 51
Material for patterns..
.140
Means of collar and wedge adjustment
of tool
36
Mechanical, department store
.127
Melting iron, small cupola for.....135
Metal, chucking of odd shaped pieces
of
86
Metal particles in file teeth.
52
Metal plates, thin in the lathe, sup-
porting
86
Metal, turning to remove
44
Metal wasted on emery wheel
48
Method of centering with chalk..... 28
Method, proper, of specifying pulleys. 82
Method of catching threads
68
Method of filling corners
..142
Method, good, of lacing belts.
16
Methods of using wood boring tools. . 102
Method of mixing plaster
95
Method of taking up wear of bearings. 22
Method of centering boring bar in
cylinder
93
Methods of tool adjustment
35
Method of using glue.
.143
Miling carriages special, for the lathe. 122
Milling, horizontal
.123
Milling attachments for the lathe. 123
Milling in the lathe
.119
Milling in the lathe, jigs for. . 107
Milling in the lathe, necessary appara-
tus for
120
Milling machine, dividing head for...121
Milling requirements
.120
Milling slide rest
.122
Minute, diameter of work giving
twenty ft. to the..
46
Minute, twenty ft. per., figuring belt
speed for
45
Mixing plaster, method of
95
Mixing slow setting plaster...
96
Mix your machines, do not do it. 119
Models for grinding lathe tools.
38
Modern box gear arrangement.
63
Modern dividing head
Molding and pattern work.
132
More scraping cuts
Motion, lost, in cross-feed screw
10
Mounted on slide rest, cylinder
91
Mounting a cylinder on a face plate. . 90
Mounting a cylinder with Plaster of
Paris
92
Mounting cylinder by the flanges
91
Mounting pipe in the lathe
154
Mount Vernon cotton belts
149
Movement of file, proper
52
Moving the tail center
24
61
.125
105
84
M
Making a handy chuck...
Making a quarter-turn crank shaft. .110
Making a star lathe dog.
.103
Making a wall bracket
..130
Machine blacksmithing
..127
Machine, milling, dividing head for..121
Machine work, the keynote of success
in
.119
Machines and tools, cost of special..120
Machines, profitable special
..108
Machines, rig up many special 119
Making center lines
113
Making drawings
127
Making holes in house moving rolls. . 101
Making lathe ready for use.
21
Making wooden rolls.
101
Making a pulley
..137
Making a pattern for a collar .104
120
N
Nature's design for fillets..
142
Necessary apparatus for milling in the
lathe
Necessary clearance for a boring tool. 69
Necessary, frequent tests of centers.. 24
Necessary straightening
31
Necessary, two surface gages.
114
Necessity of frequently dressing emery
wheels
56
New files, treatment of
52

INDEX.
ix
Nominal and actual diameter of pipes. 151
Note, key, of success in machine work.119
Not profitable to mix your machines. 119
Nut, split, and cam
11
Nut, split, on lead screw
59
Nut, wear in
10
.152
0
55
Odd shaped pieces of metal, chucking. 86
Oil, taper
. 107
Oil, use of, when chipping wrought
iron
49
Order, keeping emery wheel in
Obstinate pieces, chucking, with cal-
cined plaster
86
Obtaining a level surface for polishing. 54
Obtaining extreme accuracy
56
Obtaining fine finish
49
Outside and inside turning tools for
slide rest wood turning.
101
Overhead countershaft
Overhead drum for grinding
95
11
85
54
Overhang of tool, supporting
36
Overhead grinding rig, tool-post, for. 55
.133
.137
. 104
P
Packing steady pieces with paper. 118
Painting patterns
.142
Paper and straight-edge test..
9
Paper packing for steady-pieces. 118
Paradox, belt and pulley
147
Parallel blocks, graduated length 83
Particles of metal in file teeth.
52
Fattern corners, fillets for
142
Patterns, corners on
141
Patterns, drafting
Pattern drawings of pulley hub.
Pattern for a collar, making a
Patterns, gluing up
.143
Patterns, material for
.140
Pattern, rapping a
.134
Patterns, painting
.142
Pattern shape and proportion .132
Patterns, shrink in
.134
Patterns, split
.141
Pattern, taper or draft of
.143
Pattern, turning, for a collar .105
Patterns, turning up
..102
Pattern work and molding
.132
Pattern work, face plate
.104
Peening and lever straightening of
shafts
31
Peening, straightening by
31
Perfect screw has never been made, a. 58
Perfect turning impossible
32
Piece of work, the first
12
Pieces of metal, chucking odd shaped. 86
Pieces, chucking obstinate, with cal-
cined plaster
86
Pieces, steady, for a crank
.118
Pieces, steady, packed with paper....118
Pieces, very small, chucking with wax. 87
Picking a file
53
Pin, wrist, turning one for a crank-
shaft
118
Pipe, cutting a taper thread
.155
Pipe drive, internal..
.159
Pipe, extra shell for very large .153
Pipe, in the lathe, cutting off and
chucking
.154
Pipe, mounting, in the lathe
.154
Pipes in short lathe, threading. .159
Pipes in the lathe, threading.
151
Pipes, nominal and actual diameter of.151
Pipe, shell, center
.153
Pipes, sizes of
....152
Pipes, steam, water and gas, dimen-
sions of
....151
Pipes, threading longer than the lathe.158
Pipe tail centers, special
Pipe thread cuts, roughing and finish-
ing ...
160
Pipe threads, pitch of
.152
Pipe threads, standard taper of. 154
Pitch of pipe threads
..152
Plugging spindle with cotton waste. 81
Plumb bobs, aligning shafting with.. 20
Places, filing flat
51
Places in belt, crooked
21
Plain cast iron cones
12
Planing attachment
107
Plaster, chucking obstinate pieces with
calcined
86
Plaster, chucking work with.
95
Plaster, method of mixing
Plaster Paris, mounting a cylinder
with
92
Plaster, pouring around cylinder.... 96
Plaster, slow setting, mixing of... 96
Plate, face, bolting small work on... 79
Plate, face
79
Plate, face and work, removing wax
from
87
Plate, face, bolts and adjusting screws. 85
Plate, face, chuck, using a.
Plate, face, for patternwork
.104
Plate, face, removing center before
using
80
Plate, face, screwing on spindle too
tight
80
Plate, index
.125
Plate, index, an ancient
.124
Plate, face, large
80
Plate, face, solid.
79
Plate, lathe face, supporting an ugly
job on the
96
Plate, face, mounting a cylinder on.. 90
Plate, small slotted face
79
Plate, surface, use a
113
Plate, the index
.121
Pneumatic pulleys
.146
Pod auger
..102
Point, boiling of soda water
50
Point of tool, lowering and raising of. 36
Point of tool, projecting
48
Point of tool, sharpening
44
Point of tool worn off ..
47
Polish on lathe work, high
54
Polished, filing work to be
51
Polishing and buffing
57
Polishing in the lathe
.107
Polishing, obtaining a level surface,
for
54
Polishing or finishing irregular sur-
faces
57
Polishing wheels, construction of. 57
Polishing with chalk or clay
51
Poor grinding, steel wasted by 48
Poor practise, drilling in the lathe. 96
Position of cutting edge of tool
Post, tool, adjustment of a
35
Post, tool, importance of a good. 35
Post, tool, of lathe, hollow center in.102
Post, tool, use of the
35
Pouring plaster around cylinder 96
Power, calculations
.145
Power drill
96
Power of a belt
.148
Power, holding, of adjusting screws. 85
Power hack saw, buy a
...108
Practise, bad chuck
... 71
Practise, poor, drilling in the lathe. . 96
Press, drill, jigs for
98
Press, screw, straightening.
31
35
. . .
o.

X
INDEX.
35
Principle of water finishing cuts.... 42
Prints, core
...141
Profitable special machines.. ..108
Profit from the addition of certain
lathe tools
.107
Projection of tail spindle
27
Proper and improper punch holes.. 17
Proper length of belts, determining
the
15
Proper method of specifying pulleys.. 82
Proper movement of file
52
Proper position of cutting tool..
Proportions and pattern shapes. 132
Proper setting of boring tools.
77
Proper setting of lathe tools
39
Proper size of center drill...
29
Proper speed of lathe
44
Protecting point of tool
48
Pry-test of spindle
9
Pulleys and belts, cost of
145
Pulley and belt paradox
.147
Pulley and belt surface contact. .147
Pulley, backing or reverse
14
Pulley, balancing a
.143
Pulley, belt running on edge of. 21
Pulley, built-up
.139
Pulley, chucking a
82
Pulley, chucking a heavy
84
Pulley, chucking, straps and bolts for. 83
Pulleys, conical, badly turned
21
Pulley, use of cone or step...
34
Pulley diameters, calculating
14
Pulley diameters, formula for.
14
Fulley, draw filing a ...
147
Pulley, flanges, calculating the dimen-
sions of
.140
Pulley, go-ahead
14
Pulley hub, boring a
.143
Pulley hubs, calculating the length of.140
Pulley hubs, flanged
.137
Pulley hubs, length of
82
Pulley hub, pattern drawings of....137
Pulley, making a
. 137
Pulleys, limit to size of.
.146
Pulleys, proper method of specifying. 82
Pulleys set square and level
21
Pulleys, shafts and belts
.144
Pulley, special drive, for wood turning. 99
Pulley, thickness of flange for.. .140
Pulleys, wrought steel, split.. ..137
Pulling and pushing cuts
40
Pump logs, boring
.102
Punching holes and lacing belts.. 15
Punch holes, proper and improper... 17
Pushing and pulling cuts...
40
Putting and getting work in the lathe. 82
Putting the centers in line..
.22
Putting work into the lathe
28
Putty fillets for patterns
142
Rawhide, lacing with
17
Readings, incorrect caliper
94
Reamer, clogging of
78
Reamer for lathe spindle taper
97
Reaming
81
Reaming centers
29
Reaming in the lathe
78
Reaming spindle of lathe or drill. 97
Reference books
.132
Removing grease from files.
5
Representation of cutting speeds,
graphic
46
Remove metal at forge or foundry... 44
Remove tail center, to
26
Remove tool marks by filing..
51
Removing center before using face
plate ...
80
Removing metal, turning for.
44
Removing skids
13
Removing wax from work and face
plate
87
Requirements of milling
.120
Rest, adjusting, of, slide
26
Rest, construction of back.
38
Rest, construction of steady.
32
Rest, cylinder mounted on slide
91
Rest, slide, outside and inside, tools
for turning wood
...101
Rest, slide, wood cutting tool for...100
Rest, steady and chuck, use of the.. 70
Rest, steady, artificial bearing for.
33
Rest, steady, and its use
32
Rest, steady, setting for boring.. 74
Rests, two, steady, setting up. 32
Reversing chuck bolts
86
Reversing feed when wood turning..101
Reverse in lathe headstock....
62
Reverse pulley
14
Reversing the lathe, running carriage
back
67
Rig, overhead grinding, tool post for. 55
Rig up special machines
119
Right hand threads, change gears for
cutting
60
Rigging, chuck drill
76
Rod and screw feeds, damage to
31
Rod, center driving
81
Rod-feed and screw-feed in gear at
same time
30
Rolls, grinding hardened
56
Rolls, house moving, making holes in.101
Rolls, wooden, making of
...101
Rough and fine cylinder turning ad-
justments, making
93
Roughing and finishing cuts
48
Roughing and finishing pipe thread
cuts
....160
Roughing and finishing thread cuts,
taking
66
Roughing and finishing thread tools. 43
Rough and lumpy chips
48
Roughing cast iron
48
Roughing cut, tool setting for. 48
Roughing cut, taking a ..
49
Roughing out and finishing jigs .117
Roughing out wood for turning.
.100
Round and straight turning
32
Round-nose tools
39
Rough surfaces, chalking before mark.
ing on
Rolls, turning
.101
Rubber and leather belts
.150
Rubber belt, defect of the
.150
Rub-oil cotton belts...
.149
Rudimentary dividing head.
.121
Running back carriage by reversing the
lathe
67
Running of belt on edge of pulley.
21
Run-off, for threads
66
Q
Quality of belts
149
Quarter-turn, crank forgings ...111
Quarter-turn crank shaft, making a..110
.114
R
Radius, specify, for corners.
141
Rag wheels
57
Raising and lowering point of tool. 36
Rake and clearance of lathe tools. 37
Rake and clearance varied by tilting
tool
39
Rake of top of lathe tool
37
Rapping a pattern
134
Rats and belt lacing
16
Rawhide hammer
25

INDEX.
xi
tight
S
Safety, factor of
...129
Saving labor with jigs and attach-
ments...
.106
Saw, circular approximating speed of.136
Saw, circular, "wandering” of
137
Saw, power hack, buy a
.108
Saws, hammering circular
..136
Saw, speeding a circular
.136
Scraping cuts, more
.105
Scraping wood in the lathe
99
Scratches of file on lathe work.. 52
Screw-feed and rod-feed in gear at
same time
30
Screw, clamping of lead
30
Screw, cross-feed, lost motion in 10
Screw, chuck, for lathe
.104
Screw cutting
58
Screw cutting, compound gearing for. 62
Screw-cutting lathe, centering work in
the
.. 28
Screwing face plate on spindle too
80
Screw, lead, split nut on.
59
Screw lathe chuck
..104
Screw lathe, stud and spindle.
58
Screw lead, caution in clamping. 30
Screw, lead, tests for..
10
Screw of tool-post, test for.
36
Screw, perfect
58
Screw press, straightening with. 31
Screw, a perfect, has never been made 58
Screw, table of corrections for a. 58
Screw threads, standard..
65
Screws, adjusting, and face plate bolts. 85
Screws, holding power of adjusting.
Screws, set, calculations for... .137
Screws, set, size of
139
Second and finishing cuts..
Second hand lathe, selecting a
8
Secret of wood turning.
100
Selection and use of the file.
51
Selecting a diamond tool...
56
Selecting an emery wheel.
55
Selecting a file
52
Selection of a lathe.
7
Selecting a second-hand lathe.
8
Set, improperly in tool-post, tool.
39
Set, pulleys, square and level.
21
Set screw calculations....
137
Set-screws, size of..
..139
Set-screw, tool-post, condition of. 35
Set with tallow, emery.
57
Setting cross-feed jibs.
26
Setting cylinder with plaster
95
Setting diamond point tools.
41
Setting of boring and inside thread
tools
Setting of boring tools, proper
77
Setting of lathe tools properly
39
Setting roughing and round-nose tools. 40
Setting a boring tool.
40
Setting an internal thread tool.
40
Setting the lathe bed
13
Setting the steady rest for boring. 74
Setting the water-finish tool... 40
Setting tool for finishing cuts.
49
Setting tools in tool-post..
40
Setting tool for roughing cut.
48
Setting up the headstock..
21
Setting up two steady rests.
32
Shaft, crank, jig for turning a 112
Shafts, pulleys and belts.
144
Shafting, square
81
Shafting, standard sizes of.
81
Shafts, turning long.
32
Shape of thread-cutting tools.
64
Shapes, chucking with wooden
86
49
Shapes of metal, chucking odd.. 86
Shapes, pattern, and proportions. .132
Shafting, changing the speed of.. .137
Shafting long, straightening.
31
Shafting, straightening, by peening and
lever
31
Shafts, crank, for automobiles. .111
Shaft, crank, jigs for....
.112
Shaft, crank, laying out a.
.114
Shaft, crank, laying out a jig for a..113
Shaft, crank, turning a wrist-pin for a.118
Shaft, quarter turn, making a. ..110
Sharpening point of tool..
44
Shear, single, strength of bolts in. . 140
Shellac varnish
142
Shell, extra, for very large pipe....153
Shell pipe center.
.153
Shifting lathe belt, knack of.
22
Shimming and levelling lathe
13
Shovel, buy a, or clean the lathe. 59
Shrink, allowance for...
134
Shrink in pattern...
.134
Side clearance of lathe tool.
37
Side of a casting which is the best. 143
Side tools
39
Side tools, uses of.
40
Single shear, strength of bolts in. . 140
Signs of wear.
8
Simple and compound change gears. . 60
Simple lathe tools, form of...
38
Sizes of belt fastenings...
.149
Size of lathe, best to purchase
7
Size of pipes
.152
Size, proper, of center drill.
29
Size of pulleys, limit of..
146
Size of set screws
.139
Sizes of shafting, standard.
81
Sketches, value of
.110
Sketch habit, acquire the
.110
Skids, removing
13
Sleeve bearing
33
Slide rest, adjusting of
26
Slide rest and apron.
59
Slide-res and headstock, construction
of
21
Slide rest wood turning, outside and
ins e tools for....
Slide rest, cylinder mounteed on. 91
Slide rest for milling.
..122
Slide rest for lathe, holding bolts tap-
ped into carriage
.. 92
Slide rest wood cutting tool.
.100
Slips, Arkansas, for wood turning
tools
..101
Slip of belts
146
Slotted face plate, small.
79
Slow setting plaster, mixing.
96
Small and large drills, chucks for. 97
Small cupola for melting iron. .135
Small cylinders, boring..
89
Small pieces, chucking, with wax. 86
Small slotted face plate..
79
Small work, bolting, on face plate. 79
Small work, centering, with wax. 87
Soap suds or oil for lathe work. 50
Soda water, boiling point of.
50
Soda water for finishing cuts.
50
Soft copper hammer
25
Soft head-center
25
Solid face plate
79
Solution of sulphate of copper for
marking on bright work
114
Special machines and tools, cost of...120
Special machines, rig up many. ..119
Sepecial machines, profitable
.108
Special milling carriage for the lathe. 122
Special pipe tail centers...
..152
Special drive pulley for wood turning. 99
Specializing vs. generalizing... ..127
...101
41

xii
INDEX.
45
14
.140
• • •
Steel wasted by poor grinding. 48
Steel, wrought, split pulleys
.137
Stiff tools, using
44
Straight and accurate boring, tools for. 77
Straight and bent thread tools
39
Straight and round turning
32
Straight edge and paper test
9
Straightening and squaring-up work.. 30
Straightening by peening
31
Straightening lathe work
31
Straightening shafting by peening and
with lever
31
Straightening with chalk and anyil.. 31
Straightening with the screw press... 31
Straight or taper front bearing cones. 22
Strains caused by cooling castings...135
Straps and bolts for pulley chucking. 83
Strands, lacing, of belt, crossing.... 18
Store, mechanical department. .127
Stretch of belts ...
.150
Strength of belt splice..
17
Strength of belt splice, calculating. 17
Strength of bolts in single shear...
Strength of iron, tensile..
.128
Stud and gear
60
Studs, Blake belt
.148
Stud, spindle and lathe screw
58
Supporting an ugly job on the face
plate
96
Support of lathe
14
Supporting thin metal plates in the
lathe
86
Supporting tool overhang.
36
Surface and diameter, emery grinding,
for
56
Surface contact, pulley and belt. ..147
Surface for polishing, obtaining
level
54
115
Surface gage, constructing a.
Surface gages, two necessary.
114
Surface plate, use a
.113
Surfaces, finishing or polishing irreg-
ular
57
Surfaces, rough, chalking before mark-
ing on
114
Suds, soap, or oil for lathe work. 50
Substitute for a large chuck..
84
Surface, turning to obtain, finished. . 44
Surface speed of work in lathe.. 34
Success in machine work, the key note
of
.119
Sulphate of copper solution for mark-
ing
114
Swing between centers.
8
Swing of a lathe
8
INOO
001
a
Special tools for economy.
96
Specifying pulleys, proper method of. 82
Specify radius of corners.
141
Speed circles, lathe
47
Speeding a circular saw.
136
Speed for cast iron, cutting.
Speed for cutting brass.
45
Speed of belt for twenty ft. per min-
ute
45
Speed of circular saw, approximating.136
Speed of countershaft
Speed of lathe proper.
44
Speed of shafting, changing the.. .137
Speed of work for filing..
51
Speed of work, tools for high.
47
Speeds, graphic representation of cut-
ing
46
Speed, surface, of work in the lathe. 34
Spindle, adjustment of
9
Spindle, adjustment of lathe.
26
Spindle bearings, adjusting
22
Spindle, bearings, worn..
9
Spindle check-nut, adjustment of 22
Spindle chuck, auger shank in. 102
Spindle, clamping of
27
Spindle, condition of
9
Spindle, cones of head.
9
Spindle of lathe or drill, reaming of. 97
Spindle of lathe, taper reamer for.. 97
Spindle, projection of
27
Spindle, pry-test of
9
Spindle, screwing face plate on too
tight
80
Spindle, springing of
27
Spindle, stud and lead screw.
58
Spindle, plugging, with cotton waste. 81
Spindles, testing head and tail.
9
Splice, belt, calculating strength of.. 17
Splicing and lacing of belts.
149
Splice of belt, strength of
17
Split nut and cam
11
Split nut on lead screw.
59
Split patterns
141
Split pulleys, steel wrought
137
Spoiling tools on emery wheel.
48
Springing of lathe centers when har-
dened
25
Springing of tail spindle
27
Square and level set, pulleys..
21
Square corners, avoid in castings. 141
Squaring ends of belt
148
Square shafting
81
Square threads, the
65
Squaring-up work
30
Standard screw threads
65
Standard sizes of shafting
81
Standard taper of pipe threads. . 154
Standard thread, U. S...
64
Standard V threads
64
Star lathe dog, making a.
.103
Starting a thread..
66
Starting a thread, three ways of 66
Steady pieces for a crank.
.118
Steady rest
32
Steady-pieces packed with paper. .118
Steady rest and its uses, the
32
Steady rest and chuck, use of the. 70
Steady rest, artificial bearing for. 33
Steady rest, construction of
32
Steady rest, setting, for boring. 74
Steady rests, two, setting up
32
Steady rest without tail stock.
Steam, water and gas pipes, dimen-
sions of
151
Step cone, headstock
11
Step cones and lathe back gear.
45
Step or cone pulley and its use.
34
Steel. boring bar collar, improved. 89
Steel bushed holes in jigs
98
Surface gage
.115
T
Table of corrections for screw.
58
Tail and head spindles, testing.
9
Tail center adjustment marks.
24
Tail centers for pipe, special..
152
Tail center, hardening
25
Tail center, removing
26
Tail spindle adjustment.
9
Tail spindle, clamping of
27
Tail spindle, projection of
27
Tail spindle, springing of
27
Tail stock, blocking up.
8
Taking a roughing cut
49
Taking roughing and finishing thread
cuts
66
Taking thick cuts
44
Taking up wear of bearing, method of. 22
Tallow, emery set with
57
Taper attachment for the lathe.
.106
Taper of lathe spindle, reamer for... 97
Taper holes, boring
106-107
33

INDEX.
xiii
"Taper oil"
...107
Taper or draft of patterns.
.143
Taper or straight, front bearing cones. 22
Taper pipe thread, cutting a
.155
Tapers in the lathe, turning.
24
Tapped into slide rest or lathe car-
riage, holding bolts
92
Tapping drills
88
Taper, standard, of pipe threads. .154
Taper thread dial...
..156
Taper turning, accurate
.158
Taper work, turning
.106
Teeth, particles of metal in file, 52
Temper drawn by fast grinding.
48
Temporarily grinding a tool
44
Tensile strength of iron...
128
Test for tool-post screw
36
Testing alignment of lathe centers. 23
Testing head and tail spindles..
9
Tests for wear in the lathe bed.
9
Test lathe for truth of centers.
25
Test of centers necessary frequently.. 24
Test of spindle by prying
9
Test, straight-edge and paper
9
Tests of the lead screw.
10
The index plate
121
The lathe attachment “crank’ .119
Theory of water cut finish.
49
The Powell thread
66
Thick cuts, taking.
44
Thickness of flange.
140
Thin metal plates in the lathe, sup-
porting
86
Thread clamp for lathe carriage.
66
Thread pipe, cutting a taper.. .155
Thread cutting tools, shape of.. 63
Thread, pipe, roughing and finishing.160
Thread cuts, taking roughing and fin-
ishing
66
Thread index, using the
.157
Threads, catching
67
Threads, cutting internal
77
Threads, left hand, change gears for
cutting
61
Threads, pipe, standard taper of. 154
Threads, pipe, pitch of.
152
Threads, right hand, change gears for
cutting
60
Threads, run-off for
66
Thread, standard screw.
65
Thread, standard U. S.
64
Thread, starting
66
Thread, the square.
65
Thread tools, straight and bent. 39
Threads, V, standard
64
Thread, taper, dial
156
Thread, the Powell
66
Thread, three ways of starting
66
Thread tools
39
Thread tools, inside
39
Thread, Whitworth
65
Threading long pipes in a short lathe. 150
Threading pipes longer than the lathe. 158
Threading pipes in the lathe....151-152
Tieing up the dog
66
Tightener or binder for belts.. 148
Tight, screwing face plate on spindle
tool
80
Tilting tool, rake and clearance varied
39
Tool adjustment, collar and wedge for. 36
Tool, adjustment of, by collar and
wedge
36
Tool adjustment, method of
35
Tool adjustment for boring bar. 88
Tcol, allowance for wear in grinding. 35
Tools and jigs
96
Tools and special machines, cost of..120
Tcol and work, heat
48
Tools, belt, box for
16
Tool, chucking
76
Tool, boring, clearance necessary for a. 69
Tool-post collar
36
Tool, cooling
50
Tool, cost of diamond
56
Tool, cuttingoff
39
Tcol, cutting, proper position of 35
Tools, dull, never work with
44
Tools for cutting, cast iron...
37
Tools for high speed work..
47
Tools for straight and accurate boring. 77
Tools for turning cast iron and brass. 39
Tools, lathe, form of simple.... 38
Tools, front cutting
37
Tool, grinding front, increases clear-
ance
39
Tool-post grinding destroys the lathe. 57
Tool, grind, from bottom
44
Tool-post grinding rig
54
Tools, hand, grinding of
.106
Tools, inside and outside turning, for
slide rest wood turning
101
Tool improperly set in tool-post....39-40
Tool, lathe, distress of
48
Tools, lathe, proper setting of
39
Tools, lathe, to be added with profit. 107
Tools, lathe, use of turpentine on... 50
Tool marks removed by filing.
51
Tools, lathe, clearance and rake of. 37
Tool, lathe, top take of
37
Tool, lathe, side clearance of.
37
Tool overhang, supporting
36
Tools for cutting brass
37
Tools, lathe, common forms of.
38
Tools, lathe, models for grinding.. 38
Tool point, lowering and raising of. 36
Tool point, sharpening of
44
Tool, point of, worn off.
47
Tool post and its use
35
Tool post, adjustment of a
35
Tool post, importance of a good. 35
Tool post of lathe, hollow center in..102
Tool-post overhead grinding rig.
55
Tool, position of its cutting edge. 35
Tool, projecting point of
48
Tools, proper setting of boring 77
Tool-post screw
36
Tool-post set-screw, condition of 35
Tcol set square with work.
42
Tcol, setting for roughing cut
48
Tool, selecting a diamond
56
Tool, setting of, for finishing cuts..
49
Tools, shape of thread cutting.
63
Tools, side
39
Tool, slide rest, for wood cutting. .100
Tools, special, for economy
96
Tools, spoiling, on emery wheel.
48
Tool, temporary grinding of
44
Tools, thread
39
Tcols, inside thread.
39
Tools, thread, straight and bent 39
Tool, tilting, rake and clearance varied
by
39
Tools, two handy hand
105
Tools, using stiff
44
Tool, water finishing.
39
Tool, wedge action of lathe
49
Tools, when should be ground.
48
Tool, wood cutting, grinding a. .101
Tools, wood turning, Arkansas slips
for
...101
Tool, wood boring, method of using. 102
Top rake of lathe tool....
37
Tracking of belts
21
Traversing emery wheel past the work. 55
Treatment of new files
52
Trouble given by some belts, cause of .144
Truing centers
29
. .
by
....

xiv
INDEX.
V
Velocity diameter
.. 47
Value, doubtful, of lathe attachments.108
Value of sketches
.110
Valve cylinders, boring out..
89
Varied, rake and clearance, by tilting
tool
39
Varnish, shellac
142
Vertical and horizontal calipering. 93
V's, lathe, vertical wear in.
10
V's worn
9
V threads, standard
64
W
.....
Wall bracket, cast iron
.131
Wall bracket, making a
...130
Wax, centering small work with..... 87
Wax, chucking very small pieces with. 86
Wax, removing, from work and face
plate
87
“Wandering” of circular saw. .137
Waste, plugging spindle with cotton. . 81
Wasted by poor grinding, steel.
48
Wasted on emery wheel, metal
48
Water cuts
49
Water cut finish, theory of
49
Water cut, heat absorbed in
50
Water finishing tool
39
Water, soda, boiling point of
50
Water, soda, for finishing cuts.
50
Water, steam and gas pipes, dimen-
sions of
151
Wax, bees, fillets for patterns .142
Ways of starting a thread, three.
66
Wear in nut
10
Wear in grinding tool, allowance for. 35
Wear of bearings, method of taking
up
22
Wear of bed, tests for
9
Wear, signs of
8
Wear, vertical, in lathe V's.
10
Wedge action of lathe tool
49
Wedge adjusting, action of
36
Wedge and collar for tool adjustment. 36
Wedge and collar, adjustment of tool,
by means of
36
Weak castings
.133
Wear in apron
10
Wheel, emery, dressing necessary fre-
quently
56
Worn spindle bearings.
9
Worn V's
9
Wrist-pin, turning one for a crank-
shaft
.118
Wrought iron, use of oil when chip-
ping
49
Wrought steel split pulleys
.137
What belt to buy
.149
What kind of lathe?
11
Wheels, buffing
57
Wheel dressing, emery, frequent 56
Wheel, emery, diamond tool for dress-
ing
56
Wheel, emery, grinding with
54
Wheel, emery, spoiling tools on. 48
Wheel, emery, traversing past the
work
55
Wheels faced with leather
57
Wheel, metal wasted on emery.
48
Wheels, construction of polishing.
57
Wheels, rag
57
When straightening is necessary
31
When tools should be ground.
48
Wheel, selecting an emery
55
Width of belts
144
Width of cutting-off tools
42
Width of water finish cuts
42
.158
Truing, hardening and grinding cen-
ters
24
True lathe centers, test for.
25
Truing up work with an independent
chuck
73
Turning a crank shaft, jig for. 112
Turning adjustments, cylinder, making
rough and fine
93
Turning a center
25
Turned, badly, or conical pulleys. 21
Turning a crank wrist pin.... 118
Turning cast iron and brass, tools for. 39
Turning collar patterns
105
Turning, limit of error in.
32
Turning long shafts
32
Turning, perfect, impossible
32
Turning or drilling glass
.50
Turning rolls
101
Turning, straight and round.
32
Turning accurate tapers.
Turning tapers in the lathe.
24
Turning taper work.
106
Turning to obtain a finished surface. . 44
Turning tools, inside and outside, for
slide rest wood turning
..101
Turning tools, wood, Arkansas slips
for ..
.101
Turning to remove metal
44
Turning up patterns
.102
Turning wood, cutting instead of
scraping
.100
Turning wood in the iron working
lathe
99
Turning, wood, lathe dog
.102
Turning, wood, reversing feed when. . 101
Turning wood, roughing out for. ....100
Turning wood, the secret of... ..100
Turpentine on lathe tools, use of.. 50
Turning, wood, outside and inside,
slide rest tools for.
. 101
Turning wood, special drive pulley
for
99
Turning wood with ordinary lathe
tools.
99
Twenty feet a minute for cast iron .45, 46
Twenty feet per minute, belt speed
for
45
Twenty feet a minute, diameter of
work giving
46
Two handy hand tools..
.105
Two steady rests, setting up.
32
Two surface gages necessary
114.
Types of cotton belts
.149
U
Ugly job, supporting on the lathe face
plate
96
Usage, hard
8
United States standard threads.
64
Use and selection of file.
51
Use a surface plate
113
Use of boring bar
75
Use of the back gear.
34
Use of the chuck and the steady rest. 70
Use of the cone or step pulley. 34
Use of round-nose, cutting-off and
thread tools
39
Use of steady rest
32
Use of side tools.
40
Use of turpentine on lathe tools.. 50
Using a face plate chuck
85
Using face plate, removing center be-
fore
81
Using glue, method of
.143
Using steady-rest without tail-stock. 33
Using stiff tools
44
Using the thread index
.157
Using wood boring tools, method of.102
or CO OT OTA OTOT

INDEX.
XV
...100
...101
Wing lathe dog ..
...103
Wire belt lacing, hammering.
18
Wire lacing, excellent
18-19
Whitworth threads
65
Wood cutting lathe tool, grinding...101
Wcod cutting, slide rest tool for....100
Wood, cutting when turning...
Wood, cup center for..
..104
Wood boring tools, method of using..102
Wooden rolls, making of
Wooden shapes, chucking with
86
Wood roughing out for turning.....100
Wood, scraping
99
Wood, turning in the iron working
lathe
99
Wood turning lathe dog
.102
Wood turning, outside and inside, tools
for slide rest
Wood turning, reversing feed when..101
Wood turning, secret of
..100
Wood turning, special drive pulley for. 99
Wood turning tools, Arkansas slips
for
Work
81
Work and face plate, removing wax
from
87
Work and tool, heat between.
48
Work, bad centering of..
26
Work, chucking in the lathe
81
Work, chucking irregular
86
Work, chucking with plaster
95
Work, cut and try
110
Work, centering in the screw cutting
lathe.
28
Work, diameter of, giving twenty feet
a minute
46
...101
Work, filing, to be polished..
51
Work, file scratches in the
52
Work, filing in the lathe
50
Work, good, is impossible with a dirty
file
52
Work into lathe, putting
28
Work, lathe, high polish on
54
Work, lathe, jigs for....
98
Work, lathe, not as close as forging. .111
Work, lathe, soap suds or oil for 50
Work, machine, the key-note of suc-
cess in
..119
Work, marking on bright
..113
Work, bolting small, on face plate. . 79
Work, pattern and molding.
.132
Work, pattern, face plate
.104
Work, putting and "getting,” in the
lathe
82
Work, speed of, for filing
51
Work, speed of in the lathe.
34
Work, straightening and squaring-up. 30
Work, straightening, in the lathe.... 31
Work, traversing past the
emery
wheel
55
Work, the first piece of
12
Work, tools for high speed.
47
Work, traversing emery wheel, past
the
55
Work, turning taper
.106
Work with an independent chuck, tru-
ing up
73
Work, with wax, centering small.
Work, wood turning, outside and in-
side, slide rest tools for.. ..101
Worn lathe bed ..
9
Worn off, point of tool
47
....101
nar
87
UNIV. OF MICH.
NOV 13 1908
UNIVERSITY OF MICHIGAN
3 9015 07507 9643
62