1. General principle

Broaching produces the same surfaces as those obtained by mortising, usually in a single straight stroke of either the tool or the workpiece. Unlike mortising, broaching accepts no obstacles in the direction of travel (shoulders, blind holes). The broach (figure 1 ) has, on the same body, a succession of cutting edges spaced apart by a certain value called pitch (P ) and stepped by another value called step (h), which corresponds for each cutting edge to the quantity of material removed from the machined part. The cavity formed between two successive teeth is called the chip chamber: this is where the resulting chip coils and settles before being ejected as soon as the material has been removed. Several active zones follow one another after the first cutting tooth: a first section for roughing, a second...