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

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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.