Work is held in a vise or other attachment which is bolted to the slots of the table (Fig. 196). Wheel-shaped cutters placed on the arbor are made to revolve by means of the main spindle which is hollow, and on which is keyed the driving cone. The outer end of the arbor is supported by the adjustable over-arm. The cones are driven by a belt from similar cones overhead.
After work is secured on the machine and cutters are placed on the arbor, the table is adjusted by hand mechanism to bring the work in range of the cutters. The table may be raised or lowered by the elevating screw which controls the vertical-sliding knee, and it may be adjusted horizontally toward or from the body of the machine by moving the saddle which, in the plain machine, slides back and forth in but one horizontal direction on the knee. The table, the saddle and the knee are adjusted by means of the four cranks shown.
When the machine is in operation, with the work adjusted for cutting, the table is fed horizontally along the saddle in either direction perpendicular to the axis of the arbor, by means of the feed shaft and its mechanism. The reverse lever determines the direction of travel of the table, and the trip dogs are adjusted to stop the table within certain limits of travel as they come into contact with the trip plunger. The feed-trip lever is used to stop the feed instantly by hand. The whole feed mechanism is driven by a belt on the feed cones.
Some forms of cutters, which reach into grooves or slots in a piece of work, have their own shanks which fit into a socket or collet similar to a drill shank. This collet fits into the end of the spindle. When these cutters are used, neither the arbor nor the over-arm are used.