The cutting blades are here separate from the body of the
reamer and inserted in the latter in dovetailed slots. The
blades and the slots are inclined to the center line on their inner
surfaces in order to provide the expansion feature. When the
170 METHODS OF MACHINE SHOP WORK
reamer becomes dull, the blades are driven up the slots a slight
distance and the reamer is then placed in a grinding machine,
reground to its original size, and backed off to provide suitable
Another tool which is used in connection with reaming opera-
tions, called the four-lip drill or four-lip reamer, is shown in
Fig. 150. Twist drills or, for that matter, all drills having
two cutting edges, have no tendency to straighten holes which
are once wrongly started and, if used to enlarge a cored hole, they
will follow the eccentricity of the hole. The four-lip drill
largely corrects this tendency, the action of the two additional
cutting edges being to oppose a resistance to the tendency due
to an untrue hole to deflect the drill sidewise. When using
such a tool, if the hole is deep and the drill correspondingly
long and flexible, it is necessary, when starting to enlarge a
cored hole, to precede the four-lip drill with a short stiff tool
in order that the eccentricity of the cored hole may be corrected
by starting the hole correctly. With the hole begun in this
manner, the four-lip drill may be brought into action and,
unlike the two-lipped drill, it will follow the true start regard-
less of the deflecting action of the untrue cored hole. The hole
being made straight in this manner, the four-lip drill is followed
by the rose and fluted reamers in turn. The four-lip drill is
used for enlarging holes only. It will not drill from the solid.
FLOATING REAMER HOLDERS AND HAND REAMING
When good results are required, the final reamer must be
provided with a flexible support whereby it is free, within narrow
limits, to adjust itself in line with the hole as prepared for it.
Even though the alignment of the lathe may be of the highest
degree of accuracy, there will be enough untruth of alignment
of the lathe or of the hole to affect the finished hole if the reamer
is clamped rigidly in the turret after the manner of the other
tools, holes reamed in this manner being commonly somewhat
larger than intended and, more likely than not, larger at one
end than at the other.
Holders arranged to permit this minute adjustment of itself
TURNING AND BORING
by the reamer are called floating reamer holders. They are made
in a great variety of forms, one of which is shown in Fig. 151,
The holder is inserted in the hole of the turret, the reamer
being driven by the movable or floating feature a.
With the best of these devices there is always some resistance
to the sidewise adjustment of the reamer due to the friction
caused by the force required to hold the reamer from turning.
For this reason the best results are obtained by doing the ream-
ing operation by hand. With the reamer put through its hole
by a hand-driven wrench, it is obviously perfectly free to adjust
itself to the existing alignment of the hole and thus produce a
hole of its own size. For this reason one often sees the speci-
fication, "hand reaming only," which is intended to and does
lead to superior work.
FIG. 151. Floating reamer holder.
The author is aware of but one equipment by which reaming
may be done by power and with the same accuracy as by hand.
This equipment is shown in Fig. 152, from the Detroit works
of the Chicago Pneumatic Tool Company. The equipment
consists, first, of a cast-iron bench which is used for no other
purpose than reaming and which is fitted with oil supply and
drain pipes connected with the oil circulating system of the
factory. The reamer is driven by a compressed air motor
suspended from the ceiling by a cord, pulley and balance weight.
172 METHODS OF MACHINE SHOP WORK
The reaction due to the driving effort of the motor is resisted
by the two hands of the operator applied to the horizontal
handles. Both driving effort and resistance are true moments
without side pressure, by reason of which, and perhaps even
more than with hand reaming, the reamer is at perfect liberty
to follow the hole.
FIG. 152. Compressed air reaming bench.
THE AUTOMATIC TURRET LATHE
The most interesting of all machine tools in the almost
human intelligence which it shows is the automatic turret
lathe 1 which was developed to a state of practical usefulness
chiefly by Christopher M. Spencer, who made his first machine
1 Frequently called automatic screw machine.
TURNING AND BORING
about 1875. A prior patent by Francis Curtis issued in 1871
and another by L. W. Langdon issued in 1864 anticipate some
features of Mr. Spencer's work. For several years the machine
was not offered for sale but was used exclusively in the works
of the Hartford Machine Screw Company.
An automatic turret lathe by the Pratt and Whitney Com-
pany is shown in Fig. 153, for which, like the hand-operated
FIG. 153. Automatic turret lathe.
machine, a simple example has been chosen in order to more
clearly illustrate the principle. So far as the mounting and
action of the cutting tools are concerned, this machine is sub-
stantially identical with the hand-operated machine, but the
reciprocation and revolution of the turret, the feeding inward
and gripping of the bar of stock, and the action of the cutting-
off tool are automatically performed by means of the cams
METHODS OF MACHINE SHOP WORK
attached to the drums which are mounted on a shaft extending
through the base of the machine. In addition to this, the rate
of feed of the various tools is changed from tool to tool in order
adapt the speed to the individual cutting operation and the
direction of revolution is reversed, in order to withdraw a
threaded portion from the die which cuts the threads. The
FIG. 154. Magazine feed automatic turret lathe.
speed of the machine, as a whole, is changed by cone pulleys on
the main and countershafts.
The work spindle and the drum shaft are independently
driven in order that their speeds may be independently adjusted.
The speed of the drum shaft has no fixed relation to the speed
of the spindle, but is so adjusted that the drum shaft makes
one complete turn while one piece is being made, regardless
of the length of time required for its making. Starting at the
left, the first drum carries a series of cams by the action of which
TURNING AND BORING 175
the collet chuck is loosened and tightened and the bar of stock
is pushed forward after the cutting off of each piece. The next
cam manipulates the belt shipper which controls two belts.
The middle pulley upon the work spindle is the driving pulley,
the two outer ones being loose. One of the two belts is com-
monly crossed and serves to withdraw a threaded piece from its
die. The cam in the middle of the machine operates the cross
slide which carries a cutting-off tool and also, in a second tool
post if need be, a necking or rounding tool. The next cam drum
at the right actuates the turret slide. The return of the turret
is much quicker than the cutting movement which latter has, if
need be, a quick preliminary movement up to the point where the
cutting action begins. At the extreme right is a cam drum by
which the speed of rotation of the cam shaft is varied, for the
slow feeding and quick return movements of the turret. The
camming of these machines for various kinds of work is very
much of an art. 1
THE MAGAZINE FEED AUTOMATIC TURRET LATHE
A more recent development of the automatic turret lathe,
first made by the Pratt and Whitney Company, lies in its adap-
tation to the machining of separate pieces by taking them one
by one from a magazine, inserting them in a chuck, machining
and finally rejecting them and supplying the chuck with an-
other. So far as automatic pushing inward a bar of stock is
concerned, the work does not differ except as regards the size
of the bar. Individual castings and forgings are, however, of
such a wide diversity of form that various kinds of magazines
and as many methods of handling the pieces are required, the
provision of which often requires the exercise of much ingenuity.
Fig. 154 shows the machine as arranged for the first piece
of work to which it was adapted, the machining of the small belt
pulleys of sewing machines. A magazine, filled with blank
pulleys, is shown above the work spindle, the work of the operator
being to see to it that this magazine does not get empty. By
1 Full particulars of the methods of laying out these cams may be found in
Automatic Screw Machines and their Tools by C.L. Goodrich and F. A, Stanley.
METHODS OF MACHINE SHOP WORK
TURNING AND BORING 177
reason of the inclination of the magazine, the wheel blanks roll
to the outlet at the bottom, from which point a transfer carrier,
operated by a special cam upon the cam shaft, takes them, one
by one, and transfers them to a point in front of the spindle
chuck, into which they are pushed by the first movement of
the turret and then gripped by an additional cam action.
When the piece is finished it is automatically released from the
chuck and drops out on the floor, as shown, when its place is
taken by another through the action of the transfer carrier.
It is impossible to include any considerable number of the
numerous forms of magazine and of transfer mechanism which
have been devised to handle pieces of various forms. One
additional construction which has been designed to handle
pieces of a wide diversity of forms is shown in Figs. 155 and 156.
Comparison with Fig. 154 will serve to indicate the variety of
constructions that have been employed to meet the numerous
conditions that present themselves.
This construction is supplied with the automatic turret lathes
of the Cleveland Automatic Machine Company. Unlike all
others, the turrets of these machines turn upon a horizontal
center line. Structurally the turret is a long drum supported
by a barrel casing within which it turns and slides. The end
of the turret appears at a in both views, projecting from its
barrel support and carrying the cutting tools and the transfer
The magazine consists of a frame c mounted on a shaft d
on which it is automatically oscillated between the positions
shown in the two illustrations by a suitable cam. Surround-
ing the frame is an endless link belt, each link of which is formed
into a hub. Each hub has a hole through it endwise in which is
inserted a bush suitable for the pieces of work to be handled, the
pieces in this instance being studs, shown projecting from the
hubs. The studs are to have turning and threading operations
performed on their projecting ends. With the magazine tilted
to the position of Fig. 155, the turret advances, when the trans-
fer carrier withdraws the opposing piece of work from the maga-
zine and at the next movement of the turret transfers it to and
inserts it in the chuck. Meanwhile the magazine returns to
178 METHODS OF MACHINE SHOP WORK
the position of Fig. 156 in order to get out of the way of the
cutting tools, and remains there while the piece is being machined
and until the time arrives for the next piece to be transferred to
the chuck, when the magazine tilts to its downward position
again. During this downward movement the long pawl e
engages one of the pins in the sprocket wheel / by which the
link belt is driven and thus advances the belt and its load of
studs one link and presents a fresh stud to the transfer carrier.
In Fig. 156 one stud is seen in the transfer carrier and another in
the chuck, the latter having had the turning and threading
operations upon it performed. The die with which the thread
was cut occupies a hole in the turret in line with the second stud.
THE MULTIPLE-SPINDLE AUTOMATIC TURRET LATHE
Another comparatively recent development of the automatic
turret lathe is found in the multiple-spindle automatic turret
lathe which, although now made by several parties, was invented
by E. C. Henn of the National Acme Manufacturing Company.
In the automatic machine as so far shown, the various opera-
tions on a piece are successive, the time required to make a
piece being the sum of the times required for the individual
operations. In the multiple-spindle machine four pieces are
acted upon at once and the time required to complete the
piece becomes that of the longest single operation. 1
Referring to Fig. 157 which shows the machine of the National
Acme Manufacturing Company, we see at the extreme left four
bars of hexigon stock which pass through the same number of
hollow work spindles. The spindles are mounted and turn
within a drum which is mounted within the cylindrical head
stock and which, at the completion of each operation, makes a
quarter turn and thus shifts the bars of stock to the successive
operating positions. At the right and in line with the work
spindles are four tool supports which, while stationary in posi-
tion, revolve about their individual centers if need be. A more
1 In some cases even this is reduced by dividing the longest single operation
into two, thereby making the time required that of one -half the longest or the
entire time of the next to the longest single operation, in case that exceeds one-
half the time required for the longest.
TURNING AND BORING
FIG. 157. Multiple spindle automatic turret lathe.
FIG. 158. Arrangement of tools in multiple spindle automatic turret lathe.
180 METHODS OF MACHINE SHOP WORK
complete view of the tool supports with various tools mounted
therein is given in Fig. 158, in which are also shown surrounding
tool slides carrying cutting-off, necking and forming tools
which act simultaneously with the revolving tools, two opera-
tions at each station being frequently in progress.
The term turret lathe as applied to this machine is, in a sense,
a misnomer. The essential feature of the turrent lathe the
mounting of the tools in a revolving turret and turning them out
of and into the cutting position as required is not found in this
machine, in which the positions of the tools are fixed. On the
other hand, the position of the work is changed by presenting it
in succession to the various tools in their fixed positions. It
would more properly be called a station machine to indicate
that the work is shifted from station to station at each of which
an operation is performed. Looked at in this way, this machine
was the forerunner of a system of machines which, made at
home for special purposes, have appeared from time to time,
and which, as the multaumatic vertical lathe of the Bullard
Machine Tool Company, has now made its appearance as a gen-
eral purpose machine. The author anticipates and predicts
that machines of this type will form the next large development
in machine-shop productive equipment.
The Bullard Multaumatic machine is shown in Fig. 159. The
work-holding chucks, of which there are six, are mounted in a
revolving ring, the spindles being driven from below. Five
tools are mounted on the upright column, the sixth station being
the loading station. A piece of work being fixed in the chuck
at this point, the first step movement of the ring brings the work
below the first tool and while this tool is operating a second
piece is inserted in the second chuck and so on until all the
chucks are full. Thereafter, as each chuck arrives at the load-
ing station with the work on its piece completed, it is removed
and another substituted in its place, the operation thereafter
being continuous with five cuts in progress at all times.
AUTOMATIC LATHES FOR WORK DONE BETWEEN CENTERS
It will be observed that all of the applications of the turret
lathe shown are for work made from the bar or for pieces of a
TURNING AND BORING
nature which can be held in a chuck. The application of the
turret principle, the preservation of the adjustment of the
cutting tools, to work which must be held between centers is
a much more difficult problem, the solution of which came
much later. The customary form of turret is entirely inappli-
cable because the tools, which project radially from the turret,
FIG. 159. Station machine for lathe work.
interfere with the head and tail stocks. Two very successful
machines for this purpose are the Fay and the Lo-swing auto-
The Fay lathe, Figs. 160 and 161, is intended more espe-
cially for turning pieces which are carried on mandrels while the
Lo-swing lathe, Fig. 163, is for turning pieces of considerable
182 METHODS OF MACHINE SHOP WORK
FIGS. 1 60 and 161. Fay lathe.
TURNING AND BORING
length but of comparatively small diameter, the two machines
thus mutually supplementing each other.
As in other automatic lathes the operations of the cutting
FIG. 162. Examples of work for which the Fay lathe is adapted.
tools of the Fay lathe are controlled by cams, a cam drum,
carrying cams upon both its interior and exterior surfaces,
being located at the head-stock end of the machine. The turn-
FIG. 163. Lo-swing lathe.
ing-tool carriage is mounted upon a sliding bar which is drawn
endwise for the feed by a cam on the interior of the drum.
METHODS OF MACHINE SHOP WORK
The rear of the tool carriage rests upon a support which may
be inclined to the horizontal or be curved if desired and thus
produce both tapered and curved outlines. In the rear is a
second tool support mounted, as shown in Fig. 161, on an
arm also carried on a sliding and turning bar. This tool
support is most used for facing cuts for which it is actuated by
a heart-shaped cam within the bed. It may also be used for
turning if desired. Each tool support may carry several tools if
the work calls for them. The character of the work to which
Motor. Shaft 28s"iong 45% Carbon
Turning Time, Ready for Grinding
FIG. 164. Examples of work to which the Lo-swing lathe is adapted.
the lathe is adapted and the method of holding the cutting tools
are indicated in Fig. 162. 1
The Lo-swing lathe, Fig. 163, is a single purpose machine
intended for doing work on bar stock of the class that must be
done between centers and nothing else. The swing is reduced
to that necessary for work of three and one-half inches diameter.
It has no part corresponding to a turret but the essential feature
of the turret, the use of several tools, and the preservation of
the adjustment of the tools is retained. Two tool carriages,
1 Reproduced from Machinery.
TURNING AND BORING
each capable of holding several tools, are provided, so arranged
as to pass by the tail stock for starting the cuts and for short
work. The general character of the work for which the lathe
is adapted, together with the manner in which the successive
tools act, is shown in Fig. 164. This illustration does not,
however, show the operations of thread cutting nor taper
turning for both of which the machine is equipped.
THE BORING BAR
For a great variety of purposes holes must be bored in pieces
of a size and character such that no modification of the lathe
FIG. 165. Large boring bar at work.
can accommodate them. Such holes are bored by means of
boring bars 1 which are of three kinds: (a) those which are fed
1 The boring bar was invented in 1774 by John Wilkinson for use in the boring
of steam-engine cylinders for James Watt which, at the beginning, was the most
troublesome and difficult construction problem with which Watt had to deal.
The boring bar was of the traveling-head variety and it was the first machine
tool to approximate modern standards.
METHODS OF MACHINE SHOP WORK
through bearings with the cut, the tool being fixed in the bar;
(b) those which are stationary as regards endwise motion and
have tools fixed to them, the work traveling lengthwise of the
bar; (c) those in which both work and bar are fixed as regards
endwise motion, the tool being mounted in a traveling head
which is fed lengthwise of the bar by means of a screw.
An application of a bar of the traveling-head variety is shown
in Fig. 165 from the Westinghouse Machine Company, the work
in progress being the boring of the seats for the bearing shells
of a large upright vertical engine. The bar is supported in
FIG. 1 66. Boring bar for taper holes.
bearings, one of which is bolted to one end of the casting and
the others to cross beams as clearly shown, the drive being
through a worm gear and an electric motor belted to the worm
shaft. Such bars and their attachments naturally take a great
variety of forms in accordance with the necessities of individual
A boring bar for taper holes, from the works of the Niles-
Bement-Pond Company, is shown in Fig. 166. The bar is
swiveled to its supports and one end may be offset to any
BORING AND TURNING SPHERICAL SEAT
The growing use of the self-aligning ball-and-socket con-
struction for large bearings necessitates the provision of suitable
means for machining the spherical seats external in the case of
TURNING AND BORING
FIG. 167. Turning spherical seats for bearings.
FIG. 1 68. Boring spherical seats for bearings.
188 METHODS OF MACHINE SHOP WORK
FIGS. 169 and 170. Boring bar for spherical seats.
TURNING AND BORING 189
the bearing shells and internal in the case of their supports.
Fig. 167 from the works of the Westinghouse Machine Company
shows such a provision for the turning of the spherical seat on
a large bearing shell. The provision required is that the cut-
ting tool, instead of traveling in a straight line as in the ordinary
lathe, shall swing on the arc of a circle, the center of which is
vertically below the center line of the lathe. The means by
which this is obtained are sufficiently obvious from the
Figs. 168-170, from the same source as the last, show a
superior equipment for boring large spherical seats. Fig. 168
shows the equipment in position boring the seat of the main
bearing of a large horizontal engine. The boring bar and its
driving mechanism are suspended from a frame which is bolted
to the top of the bearing jaws. Figs 169 and 170 show the
outfit turned up on its side and from opposite ends, the frame
casting being in the background. The bar carries three tool
heads of which the outer ones, which travel on the bar for the
feed, bore the cylindrical ends of the engine casting. The inner
head swivels on the bar and is shown connected by links to
one of the traveling heads. The boring of the cylindrical ends
having been accomplished with the links removed, the cutting
tools are removed from the end heads and inserted in the swivel
head. The links being then placed in position the result of
feeding the end head along the bar is to traverse the cutting tool
on the swivel head in the arc of a circle and bore the spherical
seat. The feed screw by which the traverse is accomplished
is shown above the bar in both Figs. 169 and 170.
CYLINDER BORING MACHINES
When boring cylinders for vertical steam engines of large
size, the best practice requires that they be bored in a vertical
position in order to avoid the distortion due to their own weight
and Fig. 171 shows a machine for boring such cylinders at the
Brooklyn Navy Yard. The boring bars, of which three appear
at the left of the machine, are of the traveling-head variety and,
when at work, are supported above and below by the bearings
METHODS OF MACHINE SHOP WORK
plainly shown. The driving of the bar is from above by means of
gearing. In the foreground is a facing head for facing the
flanges of the cylinders. When mounted upon the bar its arm
FIG. 171. Large vertical cylinder boring machine and boring bars.
projects radially and the tool slide with which it is fitted
travels radially and performs the required operation.
The floor-plate system of machine tools Such tools have no defined
limit of capacity Uses of the various tools The floor-plate boring
CHARACTERISTICS OF FLOOR-PLATE TOOLS
All of the machine tools elsewhere shown have in common the
feature that the size of the work which they can normally take
in is limited by the dimensions of the machine. Numerous
ingenious expedients enable work to be done of dimensions
which exceed those for which the machines were designed, but
they are but makeshifts at best, and the growing frequency