Change-wheel.
(Machinery.) Change-wheels, having varying numbers of cogs of the same pitch, are used to connect the main arbor of the lathe with the feed-screw, so as to vary the relative rates of rotation and consequently the pitch of the screw to be cut. The first application of change-wheels to a lathe is supposed to have been in a fusee-cutting lathe, described in a work, 1741. The change-wheels are intermediate, and journaled in a bracket, which permits them to be brought into engagement with the rotative and feed wheels respectively. See screwcutting lathe; engine-lathe.