The cam-cutting attachment, [Fig. 1899], consists of a base bolted to the machine table and adjustable to any required position thereon. This base has a slide way in which a gibbed slide carrying a head is free to travel longitudinally. The pattern or former cam and the work are carried on the live spindle of the head, and the former cam is supported by circumferential contact with a roll carried on the vertical bracket shown on the right of the engraving. As shown, the device is arranged for cutting face cams, the cam-holding spindle being placed in line with the machine spindle. All that is necessary for cutting cylinder cams is to set the device with its spindle at a right angle to the machine spindle and move the supporting bracket so that its roller will meet the perimeter of the former cam. In either case the slide carrying the head is pulled forward by weights suspended over the wheel shown on the end of the base, and the feed is put on by revolving the spindle by means of the worm and worm-wheel shown in the engraving, the ordinary crank handle of the machine fitting the worm shaft.

A hand feed for cam cutters is preferable to the automatic feed, because in turning corners or curves the rate of the feed requires to be reduced in order to obtain smooth work.

[Fig. 1900] represents a universal milling machine. The live spindle head is fitted to a horizontal slide on the top of the main frame, and may therefore be moved on that slideway to adjust the cutters to the work, the motion being effected by a pinion operating a rack on the underside of the head, as shown in [Fig. 1901], which is a sectional view of the machine.

At the handle end of the pinion shaft there is provided a dial (which is seen in the [general view] of the machine) having an outer circle graduated to sixty-fourths of an inch, and an inner one graduated to fortieths of an inch. The driving shaft is at a right angle to the live spindle, and drives it by means of a hardened steel worm operating a bronze worm-wheel fast on the live spindle, and which runs in a trough of oil to provide ample lubrication.

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Fig. 1901.

The spindle is hollow and has tapered journals. The arm for supporting the outer end of the cutter arbor is cylindrical, and fits to a bore provided in the top of the frame of the head, which is split and has two binding screws. When these screws are loosened the arm may be readily adjusted for position, while when they are screwed up they lock the arm in its adjusted position. By this means the arm only projects out as far as the particular work in hand requires.

The knee for carrying the work table and chucking devices terminates at its top in a circular box cast open on top. This box is covered with a circular cap, in the upper face of which are the slideways or guides for the work table. The cap is recessed into the box so as to be kept central, and is fastened therein by an expanding ring operated by a single stud which projects through the walls of the box. This ring has a V-shaped groove on its periphery, which in expanding closes over corresponding bevelled ledges on the inside of both the cap and the box. The edge of the cap is graduated for cutting spirals.