[Illustration: Fig. 33. Rear View of Machine showing the Cross-slide Mechanism, Driving Gearing, etc.]
The cams which operate the cross-slide are mounted on the right-hand end of drum _E_ and actuate the yoke _A_ (see Fig. 33) which extends diagonally upward. The rear end of this yoke has rack teeth meshing with the teeth of a segmental pinion, which is fastened to rock-shaft _B_. At the headstock end, this rock-shaft carries another segmental pinion meshing with rack teeth formed on the cross-slide. The movement imparted to the yoke by the cams is thus transmitted through the pinions and rock-shaft to the cross-slide.
[Illustration: Fig. 34. The Automatic Controlling Mechanism for Feeds and Speeds]
The cam drum _E_ is driven by a pinion meshing with a gear attached to its front side. This pinion is driven through a train of gearing from pulley _L_ (see Fig. 34) which is belted to the spindle. The feeds are thus always dependent on the spindle speed. By means of epicyclic gearing and suitable clutches, the motion thus derived from the spindle may be made rapid for returning the turret to be indexed and then advancing it to the cutting position again, or very slow for the forward feed when the tools are at work. These changes from slow to fast or _vice versa_ are controlled by disk _D_. This disk carries pins which strike a star wheel located back of the disk at the top, and as this star wheel is turned, the speeds are changed by operation of the gearing and clutches referred to. The first pin _M_ that strikes the star wheel advances it one-sixth of a rotation, changing the feed from fast to slow; the next pin that strikes it advances it another sixth of a rotation, changing the feed from slow to fast and so on. By adjusting the pins for each piece of work, the feed changes are made to take place at the proper time. Handwheel _E_ is geared with the cam-shaft on which the star wheel is mounted, so that the feeds may be changed by hand if desired.
In addition to these feed-changing pins, disk _D_ has a dog which operates a lever by which the feed movement is stopped when the work has been completed. Four rates of feed are provided by quick change gearing of the sliding gear type, operated by handle _K_. With this handle set in the central position, the feed is disengaged. On the periphery of disk _D_ are also clamped dogs or cams _N_, which operate a horizontal swinging lever _P_ connected by a link with vertical lever _J_, which controls the two spindle speeds with which the machine is provided. Either one of these speeds can be automatically engaged at any time, by adjusting the cams _N_ on disk _D_.