Adjustable Chuck
The Hopkins patent adjustable chuck, shown in Fig. 66 is designed to grip and hold firmly and accurately any size of work from the smallest staff to the largest pinion, watch wheels of all sizes, mainspring barrels and other large work, and can be adjusted to any make of lathe by simply placing it friction tight, on a plug chuck fitted properly to the lathe. In using this chuck for staffs, pinions, wire, etc., fasten a V piece 7, of proper size, in the hole in attachment 6, taking care that both the V and the seat in which it rests are free from chips, dirt, etc. Then lay your work in the V and fasten it there by means of the sliding jaw above it. This done, place the attachment on the face of the chuck body, with the disc slipped under the heads of the two spring bolts, and then spin the work to center, same as when using wax. After centering thus, fasten the disc to place by tightening the nuts on the back ends of the spring bolts.