A cutting plate for a drill bit

摘要

An auxiliary cutting plate (10) for a multi-cutting plate drill bit (2), the auxiliary cutting plate (10) comprising a body (44) for fixing into a slot in the drill bit (2), and a profiled tip (46). The body (44) has a central longitudinal axis and the profiled tip (46) protrudes from one end of the body (44), wherein the profiled tip (46) comprises a cutting edge (62) defined by a transition between a rake face (64) and a relief face (66), wherein the rake face (64) and the relief face (66) each slope axially rearward from opposite sides of the cutting edge (62). The angle of inclination &thetas; of at least a portion of the rake face (64) measured from a plane perpendicular to the longitudinal axis decreases with increasing distance from the cutting edge (62). <IMAGE>