Machine tool , usually hydraulically operated, for finishing surfaces by drawing or pushing a cutter called a broach entirely over and past the surface.
A broach has a series of cutting teeth arranged in a row or rows, graduated in height from the teeth that cut first to those that cut last. Each tooth removes only a few thousandths of an inch, and the total depth of cut is distributed over all the teeth. Broaching is particularly suitable for internal surfaces such as holes and internal gears , but it can also shape external gears and flat surfaces.