Nikola Tesla Books
QUENCHED GAP APPARATUS 105 the chuck with the turned portion projecting. Bringing up the -18 die with the tailstock face plate against it, the die may be started with accuracy and the thread taken on the spindle. In order to cut the thread quite up to the shoulder of the unturned portion of the spindle, it will be necessary to reverse the die taking the final cut or two with the die on backwards. This completes the work on the spindle for the present. Before removing the spindle from the chuck, the No. 1 copper casting may be screwed on. The spindle is then removed from the chuck and replaced between centers with the dog as before. The surface of the copper casting may now be faced off with the assurance that it will be truly at right angles with the spindle. The edge of the casting may also be turned. The depression in the center of the casting is cut in. deep and 14 in. in diameter. This casting finished, it may be removed from the spindle and the No. 2 casting put on. The facing cut is again taken, the depression made, and the edge turned. The entire spindle with the casting is now to be reversed in the lathe, the casting first being pinned to the spindle on which it is, of course, to remain. The drive this time is by means of a stud projecting from the faceplate and engaging a screw in the periphery of the casting; the hole in which the screw is placed is subsequently used for the binding post, to which the flexible cable is attached. The spindle may now be turned to its finished diameter of ½ in. for a space of 1¾ in., and from this point to the end it is finished off to 1 in. ready for threading. The latter operation is accomplished as before by starting the die with the faceplate in the tailstock. The spindle for the lower portion of the gap casting is, of course, threaded -18 throughout its length. This operation is most easily done by gripping a piece of in. rod
