Cement Chuck
The Spickerman patent cement chuck, shown in Fig. 69, is a very handy device, as it holds and centers accurately any wheel in a watch while drilling, polishing or fitting new staffs or pinions, and all danger of injuring wheels is obviated. It fits all kinds of American or Swiss lathes. The holder shown in Fig. 70 at a, is turned down to nearly the size of the screw for the lathe and the screw cut so the holder will set as close as possible to the lathe. The face of the holder is the turned perfectly true. Put wheel to be centered in cap c, as near to center as convenient and screw on b. Then place cement face of chuck b against face of holder a on the lathe and with a lamp, warm the cement between the surfaces, holding the chuck with a stick against the pivot of wheel in the cap, and it will move to an exact center as soon as warmed sufficiently. New cement should be added occasionally between the surfaces, as it hardens and burns away and does not center as well as when new. Fig. 69 shows chuck with wheel inside ready for drilling. See also Cement Brasses.