The broaching machine is a machine tool designed and built to be able to machine grooves. To do this, he uses brushes and multi-edged cutting tools.

The principle of operation of a brush is as if it were a progressive burin, where as it advances a new burin comes into operation, there being as many as there are steps in the brush.

The design of this tool allows that, as the tool advances, each tooth of the tool cuts a little material of around 0.05 millimeters. Therefore, the length of the brush is limited by the amount of material it has to cut.

Broaching machines are used to make grooved holes that have many gears that are mounted in gearboxes to allow them to move when changing gears.

These machines are also used to machine the keyway of many pulleys and fixed gears.

The broach is a very expensive and delicate tool and that is why there are keyways with standardized dimensions and splined shafts that are also standardized.