THROWAWAY DRILL, INSERT FOR THROWAWAY DRILL, AND CUTTING METHOD USING THE THROWAWAY DRILL

摘要

A throwaway drill, an insert provided on the throwaway drill, and a cutting method using the same. The throwaway drill has a throwaway drill holder including an inner edge insert pocket having a seat, formed on a central axis side of a tip end of a drill main body, and an outer edge insert pocket having a seat, formed on the outer peripheral side of the tip end; an inner edge insert fixed to the seat of the inner edge insert pocket; and an outer edge insert fixed to the seat of the outer edge insert pocket. When viewed from the tip end side of the drill main body, the inner cutting edge of the inner edge insert includes: a first inner cutting edge provided on the central axis side of the drill main body, being parallel to at least part of the outer cutting edge of the outer edge insert; and a second inner cutting edge provided on the outer peripheral side of the drill main body, being inclined to the seat of the inner edge insert pocket in a direction toward the outer peripheral side, with respect to the first inner cutting edge.