Fig. 292. Form of Monitor Lathe.

An engine lathe equipped as described in class 1 is shown in Fig. 293. In this particular machine, the turret is of hexagona form. In the earlier machines it was usually cylindrical. It is arranged to be revolved by hand, and is released or held in place as desired by a plunger operated by the lever A and engaging in slots in the periphery of a circular plate attached to the base of the turret. The transverse position of the turret is adjusted by the cross-feed screw B; and the lateral movement or cutting feed is by the crank C, or by the power lateral feed of the lathe. The turret is pivoted to the shoe D, which is quite similar to the one shown in Fig. 291, and fits on the dovetail of the lathe carriage after the removal of the regular compound rest or tool-block. In all other respects this machine is a regular engine lathe.

Fig. 293. Engine Lathe with Hand-Revolved Turret on Carriage in Place of Tool-Block.

Fig. 294 shows the machine referred to in class 2. In this case the tailstock of the engine lathe is removed, and replaced by a base A similarly attached, which supports the turret slide B, upon which is pivoted the turret C, The base A is fixed at any desired point on the lathe bed. The turret slide B is operated by the pilot wheel D, and limited in its forward movement by the adjusting screw E. Frequently there are several of these screws in a sliding, swinging, or rotating stop-holder, by which device an adjustable stop may be provided for each tool in the turret. The regular compound rest F is retained in its place, and may be used to carry forming or cutting-off tools. The lathe proper may be any form of an engine lathe. Nearly all manufacturers of engine lathes now furnish turrets to fit either upon the carriage or upon the V's of the bed, for the purpose of doing these classes of work.

Fig. 294. Engine Lathe with Hand-Revolved Turret Mounted on Latterally Moving Slide.

The machine specified in class 3 is shown in Fig. 295. It is designed and built as a turret lathe. The base A, turret slide B, turret C, and pilot wheel D are constructed and operate as in the last example. The turret slide A is provided with an adjustable multiple-stop screw E, by which the length of cut of each individual tool in the turret is limited. A simple form of cross-slide takes the place of the carriage on the engine lathe. It is adjustable to any point on the bed. It carries two tool-blocks which may be adjusted in relation to each other by the hand-wheel G. The entire top slide carrying the two tool-posts H H is operated transversely by means of the lever J. By this device, a cutting-off tool may be carried in one tool-post, and a forming tool in the other. This machine is built in various sizes. It is equipped with chucks for taking round and hexagonal rods of different diameters; and with much larger chucks for holding castings and drop forgings which are to be bored, reamed, turned, faced, or formed. It is also provided with what is called a wire feed, by means of which long bars are automatically passed entirely through the main spindle and chuck. This device will be shown and explained in connection with Screw Machines. Provision is made for lubricating the tools by a stream of oil or other lubricant, contained in the tank K beneath the machine, whence it is drawn by a small rotary pump (not shown in the engraving) and forced up through the piping L, from which it falls upon the cutting tools.

Fig. 295. Turret Lathe, Hand-Revolved and Hand-Fed Courtesy of Pratt and Whitney Company, Hartford, Connecticut.

In Fig. 296 is shown a turret lathe fulfilling the requirements stated in class 4. The turret is mounted in substantially the same manner as in the last example, and is automatically revolved at the at End of Each Stroke

Fig. 296. Semi-Automatic Turret Lathe. Turret is Automatically Revolved.

Courtesy of Bullard Machine Tool Company, Bridgeport, Connecticut end of the return stroke. It is hexagonal in form, and the six faces are not only drilled and reamed for holding tools, but the faces are accurately surfaced, and are drilled and tapped so that large tools and special devices may be bolted to them when necessary or desirable. An elaborate and useful system of adjustable stops controls and limits the travel of individual turret tools. The cross-slide is designed more upon the lines of an engine lathe carriage, and has attached to it an apron which carries the necessary gearing for feeding purposes. The carriage carries tool-posts for one front and two back tools. The movement of the carriage on the cuts is limited by pivoted, adjustable stops for each of the three tools. There is a system of piping for the lubrication of the turret tools, and another for the three carriage tools. The headstock is triple-geared so as to give various gear as well as belt speeds and a powerful drive for heavy work. These changes of the gear speeds are made by levers, without stopping the machine. The main spindle is hollow so as to take bars through it, and the chucks are adapted to take round, hexagonal, or square bars. There is a taper attachment at the back of the carriage, by means of which tapered as well as straight work can be turned by the carriage tools.