Cotter-file. A file thin in proportion to its length, for filing out keyways or slots.

Counterbore. 1. A parallel recess at the mouth of a hole. 2. A tool for producing such a recess.

Countershaft. A shaft with pulleys upon it, employed to permit a machine to be started and stopped without stopping and starting the line shaft, also, to afford means for varying the speed of a machine.

Countersink. A tool for cutting a coned mouth to a hole.

Countersunk. Having a coned mouth.

Coupling. A piece used to connect two pieces together.

Covering-plate. A plate used to cover the seams of a boiler.

Cow-mouth chisel. A machinist’s chisel shaped at the cutting end like a carpenter’s gouge.

Crank. An arm that is fast to a shaft and is used as a lever wherewith to revolve the shaft.

Crank-shaft. A shaft having a crank.