Drill bit

Abstract

A drill bit tip construction wherein the cutting edge at the tip of the drill bit is arranged to cause fragmentation of the chips being removed from the work metal during the drilling operation. The cutting edge of the drill bit at the drilling tip is made to be wavy and, in the illustrated embodiment, is defined by a plurality of segmentally cylindrical grooves extending parallel to the longitudinal extent of the flutes at the tip. In the illustrated embodiment, the grooves have a radius of approximately 0.05" and a length substantially greater than the radius to permit repeated resharpening of the drill bit with resultant reforming of the desired wavy cutting edge in the resharpened tip. In the illustrated embodiment, the cutting edge is formed in an insert secured as by brazing in a diametric slot at the tip. The insert may be formed of a carbide material having optimum cutting characteristics. The grooves are provided in the insert by use of an electric discharge wire cutting machine.

Dependencies are inferred from the claim text.