Fig. 754.
Fig. 755.
Sometimes, as in cutting screws, the work requires to be revolved backwards, without having any lost motion between the arm and carrier, or in other words, the carrier must revolve backwards as soon as the face plate does. To accomplish this, a common plan is to tie the driver or carrier to the driving-pin, but a better plan is to employ a bent tailed dog and secure its end in the face-plate slot. A convenient form of face plate for this purpose is shown in [Fig. 754], a, b, c, and d, being slots, and e a set-screw for binding the dog as shown in [Fig. 755].
Fig. 756.
For special lathes in which the work is of uniform diameter, the driving pins p, [Fig. 753], may be replaced by solid jaws, thus in [Fig. 756] is a Clement driver, such as is used on axle lathes, c c being driving lugs in place of the pins p in figure.