Cat-head. A sleeve fastened by set-screws to slender lathe work and running in a bearing so as to steady the work.

Caulking-tool. A tool used for caulking riveted joints and in making rust-joints.

Centre-bit. A bit having a triangular conical point with its cutting edge on one-half of the end and a spur on the other half.

Centre-punch. A tool having a coned point for marking the centres to work.

Chamfer. A facet that removes the corner of a right angle.

Change-gears or change-wheels. The gear wheels employed to change the revolutions of a lead screw or feed motion.

Chaser. A toothed tool for cutting threads by hand in a lathe.

Check. A crack.

Check nut. A second nut screwed against the first to check it from slackening back.

Chip-break. A piece that rests upon the work of a wood-working machine and prevents the cutter from splitting out the wood as the cut leaves the surface.