What is a broach cutting tool?

A broach cutting tool is a slender cutting tool made from tool steel that produces a pre-determined shape on the inside or outside of a part. The broach tool has cutting teeth along its length that are tapered so the last cutting teeth are larger in diameter or taller in height than the first cutting tooth. During the broaching process the part is fixed in place and the broach tool is pulled past or through the part by a special broaching machine, or a hydraulic press in some simple applications. This progressively removes material from the inside or outside of a part, generating the desire net shape. Internal involute splines, square holes, and external notches are just a few examples of broached shapes.