HELICAL TOOTHED BROACH

摘要

A finishing broach for a work piece having helical teeth in which an elongated broach body has a multiplicity of series of helically aligned teeth and in which each tooth has sides conforming to the profile shape of the tooth spaces between adjacent teeth on the work piece, and in which the sides of each tooth are inclined to define obtuse and acute included angles at the leading corners. Each series of broach teeth has a leading and a following section. In the leading section at the acute side the teeth are all laterally stepped and backed off. At the obtuse side the teeth are neither laterally stepped nor backed off. In the following section at the obtuse side the teeth are all laterally stepped and backed off. In the following section at the acute side the first few teeth are backed off but are not laterally stepped. The following tooth is neither laterally stepped nor backed off but its side surface is chamfered from the front surface of the tooth rearwardly. The remaining teeth in the following section at the acute side are neither stepped nor backed off.