The spiral chuck is mounted on the headstock. The brass gear in the front has 96 teeth and is used for indexing spiral and reciprocator patterns. A pawl above the gear meshes with the gear and is locked in place by a cam-lock effected by the handle with the black knob. A worm gear to the right allows for finer or other divisions than those obtainable with the 96 tooth gear. The Grizzly lathe was used to machine this device.