Chapter VII: Horizontal Boring Machines

A boring machine of the horizontal type is shown in Fig. 1. The construction and operation of this machine is very different from that of a vertical boring mill and it is also used for an entirely different class of work. The horizontal machine is employed principally for boring, drilling or milling, whereas the vertical design is especially adapted to turning and boring. The horizontal type is also used for turning or facing flanges or similar surfaces when such an operation can be performed to advantage in connection with other machine work on the same part.

The type of machine illustrated in Fig. 1 has a heavy base or bed to which is bolted the column _C_ having vertical ways on which the spindle-head _H_ is mounted. This head contains a sleeve or quill in which the spindle _S_ slides longitudinally. The spindle carries cutters for boring, whereas milling cutters or the auxiliary facing arm are bolted to the end _A_ of the spindle sleeve. The work itself is attached either directly or indirectly to the table or platen _P_. When the machine is in operation, the cutter or tool revolves with the spindle sleeve or spindle and either the cutter or the part being machined is given a feeding movement, depending on the character of the work. The spindle can be moved in or out by hand for adjustment, or by power for feeding the cutter, as when boring or drilling.

The entire spindle-head _H_ can also be moved vertically on the face of the column _C_, by hand, for setting the spindle to the proper height, or by power for feeding a milling cutter in a vertical direction. When the vertical position of the spindle-head is changed, the outboard bearing block _B_ also moves up or down a corresponding amount, the two parts being connected by shafts and gearing. Block _B_ steadies the outer end of the boring-bar and the back-rest in which this block is mounted can be shifted along the bed to suit the length of the work, by turning the squared end of shaft _D_ with a crank. The platen _P_ has a cross-feed, and the saddle _E_ on which it is mounted can be traversed lengthwise on the bed; both of these movements can also be effected by hand or power. There is a series of power feeding movements for the cutters and, in addition, rapid power movements _in a reverse direction from the feed_ for returning a cutter quickly to its starting position, when this is desirable.

This machine is driven by a belt connecting pulley _G_ with an overhead shaft. When the machine is in operation, this pulley is engaged with the main driving shaft by a friction clutch _F_ controlled by lever _L_. This main shaft drives through gearing a vertical shaft _I_, which by means of other gears in the spindle-head imparts a rotary movement to the spindle. As a machine of this type is used for boring holes of various diameters and for a variety of other work, it is necessary to have a number of speed changes for the spindle. Nine speeds are obtained by changing the position of the sliding gears controlled by levers _R_ and this number is doubled by back-gears in the spindle-head and controlled by lever _J_.

The amount of feed for the spindle, spindle-head, platen or saddle is varied by two levers _K_ and _K_{1}_ which control the position of sliding gears through which the feeding movements are transmitted. The direction of the feed can be reversed by shifting lever _O_. With this particular machine, nine feed changes are available for each position of the spindle back-gears, making a total of eighteen changes. The feeding movement is transmitted to the spindle-head, spindle, platen or saddle, as required, by the three distributing levers _T_, _U_ and _V_, which control clutches connecting with the transmission shafts or feed screws. When lever _T_ is turned to the left, the longitudinal power feed for the spindle is engaged, whereas turning it to the right throws in the vertical feed for the spindle-head. Lever _U_ engages the cross-feed for platen _P_ and lever _V_, the longitudinal feed for saddle _E_. These levers have a simple but ingenious interlocking device which makes it impossible to engage more than one feed at a time. For example, if lever _T_ is set for feeding the spindle, levers _U_ and _V_ are locked against movement.

The feeds are started and stopped by lever _M_ which also engages the rapid power traverse when thrown in the opposite direction. This rapid traverse operates for whatever feed is engaged by the distributing levers and, as before stated, in a reverse direction. For example, if the reverse lever _O_ is set for feeding the spindle to the right, the rapid traverse would be to the left, and _vice versa_. The cross-feed for the platen can be automatically tripped at any point by setting an adjustable stop in the proper position and the feed can also be tripped by a hand lever at the side of the platen.

All the different feeding movements can be effected by hand as well as by power. By means of handwheel _N_, the spindle can be moved in or out slowly, for feeding a cutter by hand. When the friction clamp _Q_ is loosened, the turnstile _W_ can be used for traversing the spindle, in case a hand adjustment is desirable. The spindle-head can be adjusted vertically by turning squared shaft _X_ with a crank, and the saddle can be shifted along the bed by turning shaft _Y_. The hand adjustment of the platen is effected by shaft _Z_. The spindle-head, platen and saddle can also be adjusted from the end of the machine, when this is more convenient. Shafts _X_, _Y_ and _Z_ are equipped with micrometer dials which are graduated to show movements of one-thousandth inch. These dials are used for accurately adjusting the spindle or work and for boring holes or milling surfaces that must be an exact distance apart.

=Horizontal Boring Machine with Vertical Table Adjustment.=--Another horizontal boring machine is partly shown in Fig. 2. This machine is of the same type as that illustrated in Fig. 1, but its construction is quite different, as will be seen. The spindle cannot be adjusted vertically as with the first design described, but it is mounted and driven very much like the spindle of a lathe, and adjustment for height is obtained by raising or lowering the work table. The design is just the reverse, in this respect, of the machine shown in Fig. 1, which has a vertical adjustment for the spindle, and a work table that remains in the same horizontal plane. The raising or lowering of the table is effected by shaft _E_, which rotates large nuts engaging the screws _S_. Shaft _E_ is turned either by hand or power.

The main spindle is driven by a cone pulley _P_, either directly, or indirectly through the back-gears shown. This arrangement gives six spindle speeds, and double this number is obtained by using a two-speed countershaft overhead. The motion for feeding the spindle longitudinally is transmitted through a cone of gears, which gives the required changes, to a pinion meshing with a rack which traverses the spindle. The large handwheel _H_ and a corresponding wheel on the opposite side are used for adjusting the spindle rapidly by hand. The yoke or outboard bearing _B_ for the boring-bars can be clamped in any position along the bed for supporting the bar as close to the work as possible.

Horizontal boring machines are built in many other designs, but they all have the same general arrangement as the machines illustrated and operate on the same principle, with the exception of special types intended for handling certain classes of work exclusively. The horizontal boring, drilling and milling machine is very efficient for certain classes of work because it enables all the machining operations on some parts to be completed at one setting. To illustrate, a casting which requires drilling, boring and milling at different places, can often be finished without disturbing its position on the platen after it is clamped in place. Frequently a comparatively small surface needs to be milled after a part has been bored. If this milling operation can be performed while the work is set up for boring, accurate results will be obtained (provided the machine is in good condition) and the time saved that would otherwise be required for re-setting the part on another machine. Some examples of work on which different operations are performed at the same setting will be referred to later. The horizontal boring machine also makes it possible to machine duplicate parts without the use of jigs, which is important, especially on large work, owing to the cost of jigs.

=Drilling and Boring--Cutters Used.=--Holes are drilled in a horizontal machine by simply inserting a drill of required size either directly in the spindle _S_ (see Fig. 1), or in a reducing socket, and then feeding the spindle outward either by hand or power. When a hole is to be bored, a boring-bar _B_{1}_ is inserted in the spindle and the cutter is attached to this bar. The latter is then fed through the hole as the cutter revolves. The distinction made by machinists between drilling and boring is as follows: A hole is said to be drilled when it is formed by sinking a drill into solid metal, whereas boring means the enlargement of a drilled or cored hole either by the use of a single boring tool, a double-ended cutter which operates on both sides of the hole, or a cutter-head having several tools.

There are various methods of attaching cutters to boring-bars and the cutters used vary for different classes of work. A simple style of cutter which is used widely for boring small holes is shown at _A_ in Fig. 3. The cutter _c_ is made from flat stock and the cutting is done by the front edges _e_ and _e_{1}_, which are beveled in opposite directions. The cutter is held in the bar by a taper wedge _w_ and it is centered by shoulders at _s_, so that the diameter of the hole will equal the length across the cutter. The outer corners at the front should be slightly rounded, as a sharp corner would be dulled quickly. These cutters are made in different sizes and also in sets for roughing and finishing. The roughing cutter bores holes to within about 1/32 inch of the finish size and it is then replaced by the finishing cutter. A cutter having rounded ends, as shown by the detail sketch _a_, is sometimes used for light finishing cuts. These rounded ends form the cutting edges and give a smooth finish.

Another method of holding a flat cutter is shown at _B_. The conical end of a screw bears against a conical seat in, the cutter, thus binding the latter in its slot. The conical seat also centers the cutter. A very simple and inexpensive form of cutter is shown at _C_. This is made from a piece of round steel, and it is held in the bar by a taper pin which bears against a circular recess in the side of the cutter. This form has the advantage of only requiring a hole through the boring-bar, whereas it is necessary to cut a rectangular slot for the flat cutter.

Fig. 4 shows how a hole is bored by cutters of the type referred to. The bar rotates as indicated by the arrow _a_ and at the same time feeds longitudinally as shown by arrow _b_. The speed of rotation depends upon the diameter of the hole and the kind of material being bored, and the feed per revolution must also be varied to suit conditions. No definite rule can be given for speed or feed. On some classes of work a long boring-bar is used, which passes through the hole to be bored and is steadied at its outer end by the back-rest _B_, Figs, 1 and 2. On other work, a short bar is inserted in the spindle having a cutter at the outer end. An inexpensive method of holding a cutter at the end of a bar is shown at _D_, Fig. 3. The cutter passes through a slot and is clamped by a bolt as shown. When it is necessary to bore holes that are "blind" or closed at the bottom, a long boring-bar which passes through the work cannot, of course, be used.

Sometimes it is necessary to have a cutter mounted at the extreme end of a bar in order to bore close to a shoulder or the bottom of a hole. One method of holding a cutter so that it projects beyond the end of a bar is indicated at _E_. A screw similar to the one shown at _B_ is used, and the conical end bears in a conical hole in the cutter. This hole should be slightly offset so that the cutter will be forced back against its seat. The tool shown at _F_ has adjustable cutters. The inner end of each cutter is tapering and bears against a conical-headed screw _b_ which gives the required outward adjustment. The cutters are held against the central bolt by fillister-head screws _f_ and they are clamped by the screws _c_. Boring tools are made in many different designs and the number and form of the cutters is varied somewhat for different kinds of work.

=Cutter-heads for Boring Large Holes.=--When large holes are to be bored, the cutters are usually held in a cast-iron head which is mounted on the boring-bar. One type of cutter-head is shown in Fig. 5. This particular head is double-ended and carries two cutters _c_. The cutter-head is bored to fit the bar closely and it is prevented from turning by a key against which a set-screw is tightened. By referring to the end view, it will be seen that each cutter is offset with relation to the center of the bar, in order to locate the front of the tool on a radial line. The number of cutters used in a cutter-head varies. By having several cutters, the work of removing a given amount of metal in boring is distributed, and holes can be bored more quickly with a multiple cutter-head, although more power is required to drive the boring-bar. The boring-bar is also steadied by a multiple cutter-head, because the tendency of any one cutter to deflect the bar is counteracted by the cutters on the opposite side.

A disk-shaped head having four cutters is illustrated in Fig. 6. The cutters are inserted in slots or grooves in the face of the disk and they are held by slotted clamping posts. The shape of these posts is shown by the sectional view. The tool passes through an elongated slot and it is tightly clamped against the disk by tightening nut _n_. This head is also driven by a key which engages a keyway in the boring-bar.

Two other designs of cutter-heads are shown in Fig. 7. The one illustrated at _A_ has three equally spaced cutters which are held in an inclined position. The cutters are clamped by screws _c_ and they can be adjusted within certain limits by screws _s_. The cutters are placed at an angle so that they will extend beyond the front of the head, thus permitting the latter to be moved up close to a shoulder. The cutter-heads shown in Figs. 5 and 6 can also be moved up close to a shoulder if bent cutters are used as shown in the right-hand view, Fig. 5. The idea in bending the cutters is to bring the cutting edges in advance of the clamping posts so that they will reach a shoulder before the binding posts strike it. The arrangement of cutter-head _B_ (Fig. 7) is clearly shown by the illustration.

Cutter-heads are often provided with two sets of cutters, one set being used for roughing and the other for finishing. It is a good plan to make these cutters so that the ends _e_ (Fig. 6) will rest against the bar or bottom of the slot, when the cutting edge is set to the required radius. The cutters can then be easily set for boring duplicate work. One method of making cutters in sets is to clamp the annealed stock in the cutter-head and then turn the ends to the required radius by placing the head in the lathe. After both sets of cutters have been turned in this way, they are ground to shape and then hardened.

Boring cutters intended for roughing and finishing cuts are shown in the detail view Fig. 8 at _A_ and _B_, respectively. The side of the roughing cutter _A_ is ground to a slight angle _c_ to provide clearance for the cutting edge, and the front has a backward slope _s_ to give the tool keenness. This tool is a good form to use for roughing cuts in cast iron. The finishing tool at _B_ has a broad flat edge _e_ and it is intended for coarse feeds and light cuts in cast iron. If a round cutting edge is used for finishing, a comparatively fine feed is required in order to obtain a smooth surface. The corners of tool _B_ are rounded and they should be ground to slope inward as shown in the plan view. The top or ends _d_ of both of these tools are "backed off" slightly to provide clearance. This clearance should be just enough to prevent the surface back of the cutting edge from dragging over the work. Excessive end clearance not only weakens the cutting edge, but tends to cause chattering. As a finishing tool cuts on the upper end instead of on the side, the front should slope backward as shown in the side view, rather than sidewise as with a roughing cutter. The angle of the slope should be somewhat greater for steel than cast iron, unless the steel is quite hard, thus requiring a strong blunt tool.

=Cylinder Boring.=--Fig. 9 illustrates the use of a cutter-head for cylinder boring. After the cylinder casting is set on the platen of the machine, the boring-bar with the cutter-head mounted on it is inserted in the spindle. The bar _B_ has a taper shank and a driving tang similar to a drill shank, which fits a taper hole in the end of the spindle. The cutter-head _C_ is fastened to the bar so that it will be in the position shown when the spindle is shifted to the right, as the feeding movement (with this particular machine) is to be in the opposite direction. The casting _A_ should be set central with the bar by adjusting the work-table vertically and laterally, if necessary, and the outer support _F_ should be moved close to the work, to make the bar as rigid as possible.

The cylinder is now ready to be bored. Ordinarily, one or two roughing cuts and one finishing cut would be sufficient, unless the rough bore were considerably below the finish diameter. As previously explained, the speed and feed must be governed by the kind of material being bored and the diameter of the cut. The power and rigidity of the boring machine and the quality of the steel used for making the cutters also affect the cutting speed and feed. As the finishing cut is very light, a tool having a flat cutting edge set parallel to the bar is ordinarily used when boring cast iron. The coarse feed enables the cut to be taken in a comparatively short time and the broad-nosed tool gives a smooth finish if properly ground.

The coarse finishing feed is not always practicable, especially if the boring machine is in poor condition, owing to the chattering of the tool, which results in a rough surface. The last or finishing cut should invariably be a continuous one, for if the machine is stopped before the cut is completed, there will be a ridge in the bore at the point where the tool temporarily left off cutting. This ridge is caused by the cooling and resulting contraction and shortening of the tool during the time that it is stationary. For this reason independent drives are desirable for boring machines.

Facing arms are attached to the bar on either side of the cylinder for facing the flanges after the boring operation. The turning tool of a facing arm is fastened to a slide which is fed outward a short distance each revolution, by a star-wheel that is caused to turn as it strikes against a stationary pin. By facing the flanges in this way, they are finished square with the bore.

When setting a cylinder which is to be bored it should, when the design will permit, be set true by the outside of the flange, or what is even better, by the outside of the cylinder itself, rather than by the rough bore, in order that the walls of the finished cylinder will have a uniform thickness. The position of very large cylinders, while they are being bored, is an important consideration. Such cylinders should be bored in the position which they will subsequently occupy when assembled. For example, the cylinder for a large horizontal engine should be bored while in a horizontal position, as the bore is liable to spring to a slight oval shape when the cylinder is placed horizontal after being bored while standing in a vertical position. If, however, the cylinder is bored while in the position in which it will be placed in the assembled engine, this trouble is practically eliminated.

There is a difference of opinion among machinists as to the proper shape of the cutting point of a boring tool for finishing cuts, some contending that a wide cutting edge is to be preferred, while others advocate the use of a comparatively narrow edge with a reduced feed. It is claimed, that the narrow tool produces a more perfect bore, as it is not so easily affected by hard spots in the iron, and it is also pointed out that the minute ridges left by the narrow tool are an advantage rather than a disadvantage, as they form pockets for oil and aid in lubricating the cylinder. It is the modern practice, however, to use a broad tool and a coarse feed for the light finishing cut, provided the tool does not chatter.

The type of machine tool used for boring cylinders, and also the method of procedure is determined largely by the size of the work and the quantity which is to be machined. The turret lathe, as well as horizontal and vertical boring mills, is used for this work, and in automobile factories or other shops where a great many cylinders are bored, special machines and fixtures are often employed.

=Boring a Duplex Gasoline Engine Cylinder.=--The method of holding work on a horizontal boring machine depends on its shape. A cylinder or other casting having a flat base can be clamped directly to the platen, but pieces of irregular shape are usually held in special fixtures. Fig. 10 shows how the cylinder casting of a gasoline engine is set up for the boring operation. The casting _W_ is placed in a fixture _F_ which is clamped to the machine table. One end of the casting rests on the adjustable screws _S_ and it is clamped by set-screws located in the top and sides of the fixture. There are two cylinders cast integral and these are bored by a short stiff bar mounted in the end of the spindle and having cutters at the outer end. A long bar of the type which passes through the work and is supported by the outboard bearing _B_, could not be used for this work, because the top of each cylinder is closed.

When one cylinder is finished the other is set in line with the spindle by adjusting the work-table laterally. This adjustment is effected by screw _C_, and the required center-to-center distance between the two cylinders can be gaged by the micrometer dial _M_ on the cross-feed screw, although positive stops are often used in preference. After the first cylinder is bored, the dial is set to the zero position by loosening the small knurled screw shown, and turning the dial around. The feed screw is then rotated until the dial shows that the required lateral adjustment is made, which locates the casting for boring the second cylinder. The end of the casting is also faced true by a milling cutter. Ordinarily, milling cutters are bolted directly to the spindle sleeve _A_ on this particular machine, which gives a rigid support for the cutter and a powerful drive.

The next operation is that of boring and milling the opposite end of the cylinder. This end is turned toward the spindle (as shown in Fig. 11) without unclamping the work or fixture, by simply turning the circular table _T_ half way around. This table is an attachment which is clamped to the main table for holding work that must be turned to different positions for machining the various parts. Its position is easily changed, and as the work remains fixed with relation to the table, the alignment between different holes or surfaces is assured, if the table is turned the right amount. In this case, the casting needs to be rotated one-half a revolution or 180 degrees, and this is done by means of angular graduations on the base of the table. The illustration shows the casting set for boring the inlet and exhaust valve chambers. The different cutters required for boring are mounted on one bar as shown, and the casting is adjusted crosswise to bring each valve chamber in position, by using the micrometer dial. The single-ended cutter _c_ forms a shallow circular recess or seat in the raised pad which surrounds the opening. The cover joint directly back of the cylinders is finished by milling.

=Examples of Boring, Radial Facing and Milling.=--Another example of boring, in which the circular table is used, is shown in Fig. 12. The work _W_ is a casing for the differential gears of an automobile. It is mounted in a fixture _F_ which is bolted to the table. The casting has round ends, which are clamped in V-blocks, thus aligning the work. This fixture has a guide-bushing _G_ which is centered with the bar and cutter in order to properly locate the casting. There is a bearing at each end of the casing, and two larger ones in the center. These are bored by flat cutters similar to the style illustrated at _A_ in Fig. 3. The cutter for the inner bearings is shown at _c_.

After the bearings are bored, the circular table is turned 90 degrees and the work is moved closer to the spindle (as shown in Fig. 13) for facing flange _F_ at right angles to the bearings. Circular flanges of this kind are faced in a horizontal boring machine by a special facing-arm or head _H_. For this particular job this head is clamped directly to the spindle sleeve, but it can also be clamped to the spindle if necessary. The turning tool is held in a slotted toolpost, and it is fed radially for turning the side or face of the flange, by the well-known star feed at _S_. When this feed is in operation the bent finger _E_ is turned downward so that it strikes one of the star wheel arms for each revolution; this turns the wheel slightly, and the movement is transmitted to the tool-block by a feed-screw. The illustration shows the tool set for turning the outside or periphery of the flange. This is done by setting the tool to the proper radius and then feeding the work horizontally by shifting the work-table along the bed. By referring to Fig. 12 it will be seen that the facing head does not need to be removed for boring, as it is attached to the spindle driving quill and does not interfere with the longitudinal adjustment of the spindle. This facing head is also used frequently for truing the flanges of cylinders which are to be bored, and for similar work.

Fig. 14 shows another example of work which requires boring and milling. This casting is mounted on a fixture which is bolted to the main table. In this case the circular table is not necessary, because the work can be finished without swiveling it around. After the boring is completed the edge _E_ is trued by the large-face milling cutter _M_ bolted to the spindle sleeve. The irregular outline of the edge is followed by moving the table crosswise and the spindle vertically, as required.

=Fixture for Cylinder Lining or Bushing.=--A method of holding a cylinder lining or bushing while it is being bored is shown in Fig. 15. The lining _L_ is mounted in two cast-iron ring-shaped fixtures _F_. These fixtures are circular in shape and have flat bases which are bolted to the table of the machine. On the inside of each fixture, there are four equally spaced wedges _W_ which fit into grooves as shown in the end view. These wedges are drawn in against the work by bolts, and they prevent the lining from rotating when a cut is being taken. This form of fixture is especially adapted for holding thin bronze linings, such as are used in pump cylinders, because only a light pressure against the wedges is required, and thin work can be held without distorting it. If a very thin lining is being bored, it is well to loosen the wedges slightly before taking the finishing cut, so that the work can spring back to its normal shape.

=Horizontal Boring Machine of Floor Type.=--The type of horizontal boring, drilling and milling machine, shown in Fig. 16, is intended for boring heavy parts such as the cylinders of large engines or pumps, the bearings of heavy machine beds and similar work. This machine can also be used for drilling and milling, although it is intended primarily for boring, and the other operations are usually secondary. This design is ordinarily referred to as the "floor type," because the work-table is low for accommodating large heavy castings. The spindle _S_ which drives the boring-bar, and the spindle feeding mechanism, are carried by a saddle. This saddle is free to move vertically on the face of column _C_ which is mounted on transverse ways extending across the right-hand end of the main bed. This construction permits the spindle to move vertically or laterally (by traversing the column) either for adjusting it to the required position or for milling operations. The spindle also has a longitudinal movement for boring. There is an outer bearing _B_ for supporting the boring-bar, which also has lateral and vertical adjustments, so that it can be aligned with the bar.

The work done on a machine of this type is either clamped directly to the large bed-plate _A_ (which has a number of T-slots for receiving the heads of the clamping bolts) or, in some cases, a special fixture may be used or an auxiliary table. Boring machines of this same general construction are built in many different sizes. The main spindle of the machine illustrated is driven by a motor located at the rear of the vertical column _C_, the motion being transmitted to the spindle through shafts and gearing. The casting _D_, shown in this particular illustration, is for a steam engine of the horizontal type, and the operation is that of boring the cylindrical guides or bearings for the crosshead. These bearings have a diameter of 15-3/4 inches and are 37-3/4 inches long. In boring them, two roughing cuts and one finishing cut are taken. The end of the casting, which in the assembled engine bears against the cylinder, is then faced by means of a regular facing arm.

After removing the boring-bar the table _E_ of the special fixture on which the casting is mounted is turned one quarter of a revolution. A large milling cutter 24 inches in diameter is next mounted on the spindle of the machine, and one side of the main bearing, as well as the pads for the valve-rod guide-bar brackets, are milled. The table is then revolved and the opposite side of the main bearing is milled in the same way, the table being accurately located in the different positions by an index plunger _F_ which engages holes on the under side. The spindle is now moved upward to allow the table to be turned so as to locate the bearing end of the frame next to the headstock of the machine. The milling cutter is then used to machine the inside and top surfaces of the main bearing. By turning the fixture and not changing the position of the casting after it is bolted into place, the various surfaces are machined in the correct relation to one another without difficulty. This is a good example of the work done on horizontal boring machines of the floor type.

INDEX

PAGE

Acme flat turret lathe, examples of chuck work 219
Acme standard thread and tool for cutting 159
Acme standard thread gage 157
Acme thread tool, measuring width with vernier caliper 157, 158
Accumulation of errors 105, 106
Aligning lathe centers for cylindrical turning 16
Allowances, average, for forced fits 130
for different classes of fits 131
for driving fits 131
for forced fits of given pressure 133
for push fits 131
for running fits 131
for shrinkage fits 133
Aluminum, lubricant for machining 53
shape of tools for turning 53
speed and feed for machining 53
Angle-plate applied to lathe faceplate 48
Angles, gage for accurate measurement of 97
Apron of lathe 4, 5
Arbor or mandrel press 22
Arbors or mandrels for lathe work, types of 19
use of 17
Attachment, application of Hendey relieving 125
convex turning for vertical boring mill 259
for coarse threading in lathe 160
for spherical turning 113
for taper turning in lathe 88
Hendey relieving 123
Automatic chucking and turning machine, Potter & Johnston 223
Potter & Johnston, method of "setting-up" 227
Potter & Johnston, turning flywheel in 236

Back-gears of lathe 3, 4
Bardons & Oliver turret lathe, general description 178
Bored holes, measuring diameter of 41
Boring and reaming tools for vertical mill 251
Boring and turning mill, vertical, general description 242
vertical, holding and setting work 247
vertical, turning in 249
Boring and turning mill, vertical, turning tools for 253
Boring-bar cutters and methods of holding 280
Boring cutters for roughing and finishing cuts 285
Boring cylinders on horizontal machine 286
Boring holes to given center distance in lathe 51
Boring in lathe, example of 39
Boring large castings in lathe 49
Boring large holes, cutter-heads used for 283
Boring machine, horizontal 275
horizontal, examples of work on 289-297
horizontal, floor type 294
vertical, multiple-spindle type 274
Boring tool, lathe 40
Box-tools, different designs and examples of work 193
for general turret lathe work 190
Bradford belt-driven lathe, general description 1
Bradford quick change-gear type of lathe 173
Brass, speed for turning 52
tool for turning in lathe 52
"Bridle" or "hold-back" for lathe 26, 27
Bullard vertical turret lathe 264
examples of work 268
Button method of locating work 101

Caliper tool for taper turning 85
Calipers, methods of setting 10, 11
"Cat-head," application in lathe work 25
Center holes, incorrect and correct forms 32
Center indicator, use of 100
Centered stock, methods of facing ends 34
Centers, lathe, aligning for cylindrical turning 16
lathe, grinder for truing 34
Centering machine 30
Centering parts to be turned 28
Centering, precaution for tool steel 33
Change gears, calculating for thread cutting 167
compound, for thread cutting 170
for cutting fractional threads 171
for cutting metric pitches 171
for thread cutting 135
Chasing dial for "catching threads" when screw cutting 141
Chuck, inaccuracy from pressure of jaws 42
lathe, application of 37
setting work in 42
universal, independent and combination 36
Chucking and turning machine, Potter & Johnston automatic 223
Potter & Johnston automatic, method of "setting-up" 227
Potter & Johnston automatic, turning flywheel in 236
Chucking machine, New Britain, multiple-spindle type 238
Clearance angle for turning tools 66
Clearance of turning tools, meaning of 62, 63
Coarse threading attachment for lathe 160
Collapsing tap, Geometric 202
Combination chuck for lathe 36
Compound rest, applied to screw or thread cutting 143
applied to taper turning 95
Convex turning attachment for vertical boring mills 259
Copper, tool for turning in lathe 52
Crankshaft lathe, description of R. K. LeBlond special 108
operation of R. K. LeBlond 110
Crankshaft turning in engine lathe 107
Cross-slide stop for threading 155
Cuts, average depth for turning 75
roughing and finishing in lathe 12, 75, 76
Cutter-heads, for boring, equipped with adjustable tools 284, 285
for horizontal boring machine 283
Cutters, boring, roughing and finishing types 285
for boring-bars 280
Cutting lubricants for turning tools 77
Cutting speeds, average for turning 72
based on Taylor's experiments 71
effect of lubricant on 76
factors which limit speeds for turning 72
rules for calculating 74
Cylinder boring machine, multiple-spindle type 274
Cylinder boring on horizontal machine 286
Cylinder lining, fixture for holding when boring 293
Cylindrical turning, simple example of 6

Davis turret lathe, turning bevel gear blanks 212
turning worm-gear blanks 211
Depth of cut for turning, average 75
Detrick & Harvey horizontal boring machine, floor type 294
Dial for "catching threads" when screw cutting 141
Dial gage, testing concentricity of button with 103, 104
Die and tap holders, releasing 199
Die-heads, self-opening type 200
Disk gage, for angles and tapers 97
rules for setting 98, 99
Dogs or drivers, lathe, application of 16
Drill, flat, for lathe 44
Drilling and reaming in lathe 43
Drivers or dogs, lathe, application of 16
Driving fits, allowances for 131

Eccentric turning in lathe 106
Engine lathe, general description 1
Errors, accumulation of 105, 106

Faceplate, indexing for multiple-thread cutting 153
lathe, application of angle-plate to 48
lathe, holding work on 45
Facing ends of centered stock, different methods 34
Feed and depth of cut for turning, average 75
Feeds and speeds for turning based on Taylor's experiments 71
Filing and polishing in lathe 13
Finishing and roughing cuts in lathe 75, 76
Fits, allowances for different classes 131
different classes used in machine construction 129
driving, allowances for 131
forced, allowances for given pressure 133
forced, average allowance for 130
forced, pressure for 132
push, allowances for 131
running, allowances for 131
shrinkage, allowances for 133
Fixture for holding thin lining when boring 293
Flat drill and holder for lathe 44
Flat turret lathe, Acme, examples of chuck work 219
Hartness, example of turning 213
Jones & Lamson double-spindle type 221
Floating reamer holders 271
Flywheel, finishing in one setting in turret lathe 186
finishing in two settings in turret lathe 189
machining in turret lathe 184
turning in Potter & Johnston automatic 236
turning in vertical boring mill 255
Follow-rest for lathe 27
Forced fits, allowances for given pressure 133
average allowance for 130
pressure generally used in assembling 132
Fractional threads, change gears for cutting 171

Gage, disk, for angles and tapers 97
disk, rules for setting 98, 99
for testing V-thread tool 138
standard plug, for holes 42
thread, Acme standard 157
Geometric collapsing tap 202
Geometric self-opening die-head 200
Gisholt convex attachment for vertical mill 259
Gisholt vertical boring mill, general description 242
Grinder for truing lathe centers 34
Grinding lathe tools 62

Hartness flat turret lathe, example of turning 213
Hendey relieving attachment 123
application of, for relieving taps, cutters and hobs 125
"Hold-back" or "bridle" for lathe 26, 27
Hollow mills for turret lathe 198
Horizontal boring machine 275
Detrick & Harvey floor type 294
examples of work 289-297

Independent chuck for lathe 36
Index plate, change gear, for lathe 137
Indicator, center, use on lathe 100
for "catching threads" when screw cutting 141
test, truing buttons with 102, 103
thread, for lathe apron, principle of 142
Inserted cutter turning tools for lathe 58
Internal threading 154

Jones & Lamson double-spindle flat turret lathe 221

Knurling in lathe and tool used 122

Lard oil as a cutting lubricant 78
Lathe, boring holes to given center distance in 51
boring large castings in 49
boring small hole with 104, 105
cutting threads in 135
drilling small hole with 104
general description of Bradford 1
LeBlond crankshaft, operation of 110
Lo-swing, general description 115
method of handling when cutting threads 138
quick change-gear type 173
R. K. LeBlond special crankshaft 108
turret type, general description 178
Lathe centers, grinder for truing 34
Lathe chucks, application of 37
universal, independent and combination 36
Lathe faceplate, holding work on 45
Lathe follow-rest 27
Lathe steadyrest 23
application of, when boring 25
Lathe taper attachment 88
practical application of 90
Lathe tool grinding 62
Lathe tools, angle of clearance 66
angle of keenness 67
application of various types 56
slope of cutting edge 66, 67
Lathe turning tools, inserted-cutter type 58
set of tools for general work 54
Lead of thread, definition of 146
LeBlond, R. K., lathe for crankshaft turning 108
Left-hand thread, method of cutting 148
Lining, fixture for holding when boring 293
Lo-swing lathe, general description 115
example of multiple-turning 117
Lubricant, effect on cutting speed 76
for cooling turning tools 77
for machining aluminum 53
lard oil as a cutting 78
Lucas horizontal boring machine 275

Mandrel or arbor press 22
Mandrels or arbors for lathe work, types of 19
for lathe work, use of 17
Metric pitches, change gears for cutting 171
Micrometer for measuring threads 162
Mills, hollow, for turret lathe 198
Multiple-spindle chucking machine, New Britain 238
Multiple-thread cutting, indexing faceplate for 153
Multiple threads 146
method of cutting 150
setting tool when cutting 152
Multiple-turning in Lo-swing lathe 117

New Britain multiple-spindle chucking machine 238
Newall Engineering Co's fit allowances 131

Pistons, gasoline engine, turning in turret lathe 204
Piston rings, attachment for turning in turret lathe 210
turning in turret lathe 206
Piston turning in Pratt & Whitney turret lathe 208
Pitch, metric, change gears for cutting 171
Pitch of thread, definition of 146
Plug gage, standard 42
Polishing and filing in lathe 13
Potter & Johnston automatic chucking and turning machine 223
method of "setting-up" 227
turning flywheel in 236
Pratt & Whitney turret lathe, arranged for piston turning 208
equipped with piston ring turning attachment 210
Press for arbors or mandrels 22
Pressure generally used in assembling forced fits 132
Push fits, allowances for 131

Quick change-gear type of lathe 173

Reamer holders, floating type 271
Reaming and drilling in lathe 43
Releasing die and tap holders 199
Relieving attachment, Hendey 123
Relieving attachment, Hendey, application of 125
Relieving hobs or taps having spiral flutes 128
Rivett-Dock threading tool 164
Roughing and finishing cuts in lathe 75, 76
Running fits, allowances for 131

Screw cutting, calculating change gears for 167
compound gearing for 170
in engine lathe 135
method of handling lathe 138
selecting change gears for 135
with compound rest 143
Screws, cutting to compensate for shrinkage 165
metric, change gears for cutting 171
testing size of 161
Selecting type of turning machine 240
Shrinkage, cutting screws to compensate for 165
Shrinkage fits, allowances for 133
Side-tool, facing with 7
Speeds for turning, average 72
based on Taylor's experiments 71
effect of lubricant 76
factors which limit 72
rules for calculating 74
Spherical turning 111
attachments for 113
"Spider" for supporting bushing while turning 48, 49
Spiral flutes, method of relieving hobs or taps with 128
Square thread and method of cutting 149, 159
Steadyrest, application of when boring 25
for engine lathe 23
Stop for lathe cross-slide when threading 155

Tap and die holders, releasing type 199
Taper attachment for lathe 88
practical application of 90
Taper boring with taper attachment 90
Taper threading, position of tool for 154
Taper turning, adjustment of tailstock center for 82
by offset-center method 80
examples of 83
height of tool for 94
in vertical boring mill 261
in vertical mill with horizontal and vertical feeds 262
setting tailstock center with caliper tool 85
setting tailstock center with square 87
with compound rest 95
with taper attachment 92, 93
Tapers, gage for accurate measurement of 97
Tapers, rules for figuring 97
Test indicator, truing buttons with 102, 103
Test or center indicator for use on lathe 100
Thread cutting, calculating change gears for 167
compound gearing for 170
cross-slide stop used for 155
indexing faceplate for multiple threads 153
in engine lathe 135
internal 154
method of handling lathe 138
selecting change gears for 135
taper, position of tool for 154
with compound rest 143
Thread gage, Acme standard 157
Thread indicator for lathe apron 141, 142
Thread micrometer 162
Thread tool, Acme, measuring width with vernier caliper 157, 158
for cutting V-thread 138
Thread tools for standard threads 159
Threads, Acme standard, and tool for cutting 159
change gears for fractional 171
cutting to compensate for shrinkage 165
different forms of 144
left-hand, method of cutting 148
metric, change gears for cutting 171
multiple 146
multiple, method of cutting 150
multiple, setting tool when cutting 152
sharp V, and tool for cutting 159
square, and method of cutting 149, 159
testing size of 161
three-wire system for measuring 163
U. S. standard, and tool for cutting 146, 159
Whitworth standard, and tool for cutting 158, 159
worm, and tool for cutting 159, 160
Threading attachment, lathe, for coarse threads 160
Threading tool, Rivett-Dock 164
Tool grinding 62
Tools for lathe, set for general turning 54
Tools for turning, angle of clearance 66
angle of keenness 67
inserted-cutter type 58
slope of cutting edge 66, 67
Tools for turret lathe 190
Tools, lathe, application of various types 56
Turning, cylindrical, simple example of 6
eccentric 106
multiple, in Lo-swing lathe 117
with front and rear tools 114
Turning speeds, average for lathe 72
based on Taylor's experiments 71
factors which limit 72
rules for calculating 74
Turning tools, angle of clearance 66
angle of keenness 67
for aluminum 53
for brass 52
for copper 52
for lathe, position of 60
for lathe, set of, for general work 54
inserted-cutter type for lathe 58
slope of cutting edge 66, 67
Turret lathe, Bardons & Oliver, general description 178
examples of chuck work in Acme flat 219
Hartness flat, example of turning 213
Jones & Lamson double-spindle type 221
machining flywheels in 184
Pratt & Whitney arranged for piston turning 208
piston ring turning attachment for 210
tools for general work 190
turning bevel gear blanks in Davis 212
turning gasoline engine pistons in 204
turning piston rings in 206
turning worm-gear blanks in Davis 211
typical example of turret lathe work 181
Turret lathe tools, miscellaneous types 202
Turret lathe type of vertical boring mill 264
Type of turning machine, factors which govern selection 240

U. S. standard thread 159
method of cutting 146
Universal chuck for lathe 36

V-thread and tool for cutting 159
Vertical boring mill, Bullard turret lathe type 264
convex turning attachment 259
general description 242
holding and setting work 247
taper turning in 261
taper turning with horizontal and vertical feeds 262
tools for boring and reaming 251
turning flywheel in 255
turning tools for 253
Vertical turret lathe, Bullard, examples of work 268

Whitworth standard thread and tool for cutting 158, 159
Wire system for measuring threads 163
Worm thread and tool for cutting 159, 160

Transcriber's notes on changes made to text:
Left as in original:
use of degree, deg. and deg.; use of minute, min. and '.

Standardised to the most commonly used in the book:
backgear to back-gear; camshaft to cam-shaft; crankpin to
crank-pin; face-plate to faceplate; out-board to outboard;
over-hang to overhang; setscrew to set-screw; steady-rest
to steadyrest; subdivision(s) to sub-division(s); tail-stock
to tailstock; thumbscrew to thumb-screw; tool-post to toolpost;
tool-slide to toolslide; hand-wheel to handwheel; U.S. to U. S.

Page 64 had a blotched (illegible) word, this has been replaced by
(large and rigid) work.

Table of Contents: largely re-compiled to create one-to-one links
with named paragraphs and sections in text.

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