Two-stage progressive drawing machine for processing cylindrical holes

Abstract

This utility model relates to metal-cutting tools for broaching cylindrical holes. The technical result consists of increased machining productivity, reduced broaching force, vibration, and specific pressure on the teeth, increased tool life and hole machining quality, and expanded broach manufacturing capabilities. The two-stage progressive broach has a front shank, a neck, a transition cone, a front guide, a two-stage cutting section, a calibrating section, a rear guide, and a rear shank. The first-stage cutting teeth have splined straight-sided cutting lugs and chip-separating grooves on each cutting lug; the second-stage teeth have staggered chip-separating grooves on each tooth. In the calibrating section, two pre-calibrating teeth are made in front of the round calibrating teeth, and the transition section between the steps is made enlarged.