two sets of pinions and wheels enables two differing ratios to be had, as desired, according to the size of the work tooled. In conjunction with the countershaft, twelve speeds in all can be got to the spindle.

The principles of spindle gripping and feeding mechanisms are practically the same in all

P

Fig. 168.-Rear-end Elevation of Wolseley Head.

machines. The sectional drawing, Fig. 167, of the spindle of a machine by the Wolseley Tool & Motor Car Co., Ltd., represents the typical pattern, which differs only in proportions and details in other types. Here it will be seen that three pulleys, A, B, and C, are mounted, not directly upon the spindle, but upon a bush or

sleeve D, held in the headstock holes. This relieves the spindle E of all side strain due to the pull of the belts, and prevents uneven wear. The pulleys a and c run loose upon the sleeve D, at different rates, fast and slow, and either can be thrown on separately to the wide middle driving pulley B, attached to a ring keyed on the spindle. A ball thrust is fitted next this collar, to relieve the end pressure. Fitting within the spindle bore is a long tube F, having at its end a split chuck G, tapered to jam into a plug screwed in the spindle end. Within F is another tube H with a spring split end screwed to it. Compare with the end view, Fig. 168.

It will be evident that the act of pushing F outwards would grip the chuck end around a bar fitting snugly within it, and this function is performed by the two levers J, J, the hooked ends of which press against the face of a collar, touching the end of F. These levers are actuated by the sliding ring L, the body of which coerces the roller ends of J, J, causing them to open out. L is moved along by a slide м, which is driven by a cam strip attached to the cam drum N, set to just close the chuck sufficiently tight. The tube H is also slid endwise, by a slide o, also actuated by a roller pushed by a cam strip on N. These pins have been referred to previously in a similar class of fitting, mentioned in connection with Figs. 163 and 164.

The sequence of operations is as follows:When a bar is to be loosened, the slide м goes to the right (in the position seen in the figure), thus allowing the spring chuck to release itself from the bar. The slide o then travels to the right, pushing the tube H, on the end of which is the split portion. The latter is made to just grip the bar, so that it is carried along with the tube. This constitutes the feed of the bar. When the length of travel desired is reached, м moves to the left, pressing levers J, J, on the end of F, and tightening the chuck around the bar. Slide o then moves to the left again, drawing back the tube H, with its feeding finger, ready for another pushing of the bar when desired, after the tooling operations are finished. For working the chuck by hand, when making adjustments in setting, the hand lever P is provided, actuating the slide M.