improvements in drill with adjustable elements in predetermined positions reported

摘要

An indexable insert drill employing a plurality of inserts located substantially in a single radial plane characterized by a round innermost insert having its arcuate cutting edge extending across the axial center line of the drill. One or more supplemental inserts, preferably square in configuration and including chip interruption notches positioned for positive axial lead, continue the cutting action radially beyond the arcuate center cut of the round insert with an outermost corner adapted to finish cut the side wall diameter of the hole.