A form of strap not unusually employed for work chucked in this manner is shown in [Fig. 871], its advantage being that it is capable of more adjustment about the chuck plate, because the slots afford a greater range for the bolts to come even with the holes in the chuck plate.
Fig. 872.
Fig. 873.
If the work be light, it may be held to the face plate while the holding or clamping plates are applied as shown in [Fig. 872], in which f is the face plate or chuck plate, w the work, p a plate of iron, d a rod, and c the back lathe centre. The latter is forced out by the hand wheel of the tailstock with sufficient force to hold the work by friction while the bolts and plates are applied. It is obvious, however, that if the work has no hole in its centre, the plate p may be dispensed with, and that if a strap plate, such as shown in [Fig. 871], be employed, it must first be hung on the tail spindle so that it may be passed over the rod d to the work. Strap plates are suitable for work not exceeding about 6 inches in diameter. For larger work, bolts and plates are used, as shown, for example, in [Fig. 873], which represents a piece of work w held to the chuck plate by plates p and bolts b, there being at e e packing pieces or pieces of iron to support those ends of the clamps or clamping plates p. It is necessary that these packing pieces e be of such a height as to cause the plates p to stand parallel to the face of the chuck for the following reasons:—
