The piston A shown in Fig. 7 is held by the inside on a special expanding pin chuck B. The arrangement of tools is that recommended by the Pratt & Whitney Co., for turning automobile pistons on their horizontal turret lathe. The turning tool-holder C is of cast iron and is double ended, reaching entirely across the turret, and the two ends are exactly the same. The body or arm is of U-section and it is cored out at the center so that the turret binder-lever can pass through it, as shown at G. A careful fit is made on the dovetail at D, and two special bolts F pass down through the body of the tool and pull up the gib E against the lower dovetail, thus clamping the tool securely. The tool J is backed up by the collar-head screw H and is secured by means of two screws. The steel pilot K fits the bushing L in the spindle cap bracket M, as in a previous instance. It will be noted that an air hole 0 is provided where the shank P enters the end of the tool body. In connection with the turning tools a special block on the cut-off slide is used to cut the ring groove in the piston. This block and tools are shown at R and Q in the upper view. This style of equipment is very well known and has given universal satisfaction.

Fig. 7. Double-end Piloted Turning Tool for Pistons.

Fig. 8. Piston Turning: Tool having Adjustable Tool-block.

Piston Turning- Tool having Adjustable Tool-block A development of the preceding tool is shown in Fig. 8. It will be noted that although the general construction is about the same, in this instance the tool-block is made separate so that other blocks may be substituted having more than one tool. Considerable adjustment is also permissible by means of slots shown at D. It is obvious that this method of construction requires the tool-block B to be of steel and somewhat heavy, so that it will properly resist the thrust of the cut. The screws which hold the block in position must also be of ample size. As this particular tool was designed for use in turning and boring ring pots, in addition to piston work, the boss E was supplied and bored at F to receive a boring-bar.

Special Multiple Turning Tool with Roller Back-rest In a great many instances the design of an automobile piston is such that it is permissible to center the solid end, and this gives a chance to support the end by a conical rest. While the ring grooves are being cut some support is essential, and in the case of the piston shown in Fig. 9 the use of roller supports in place of a center rest was found necessary for the reason that centering was not permitted. The piston A is held on the special chuck B and the two tools E and F are held in a double-end tool-holder. Adjustment is obtained by means of the collar-head screws H and G. The turning tool body C fits the turret dovetail at D and it is clamped, as previously stated. The end of the pilot K is cut away on its under side in order to clear the gear guard L. The steel supports 0 are backed up by the screws Q, which are also used for adjusting purposes. The hardened and ground steel rollers P are hung on the pins 8. (See detail view.) A special tool-block M contains the grooving tools N. This equipment also was very successful.

Adjustable Piloted Turning Tool for Large Diameters A somewhat different type of tool is shown in Fig. 10, this being adjustable for various diameters from the 12-inch casting A down to a diameter of 6 inches or a trifle under that size if necessary. This tool was rather heavy and cumbersome and not entirely successful on heavy cuts. On the lighter variety of work, however, it proved satisfactory and adaptable. Two tools were used on opposite sides of the turret; the flat steel tie-bar L helped to prevent sagging.

Fig. 10. Adjustable Piloted Turning Tool for Large Work.

The body of the holder B is of cast iron cored out so that the walls are 1/2 inch section, and it is tongued along its lower face to fit the turret at M. The forward end holds the steel pilot C, which is supported and guided by the bushing D. The bracket E is fastened to the head of the machine by the screws F, thus insuring a rigid support for the end of the pilot. The tool-slide N contains the tool 0 and it is securely gibbed by the two steel straps P. A taper gib (not shown) provides adjustment for wear on the sides. The bracket K is screwed to the top of the tool body and journals the operating screw H. A graduated collar permits accurate settings to be made without trouble. A bronze nut in the body of the slide at J receives the operating screw.