Patent ID: 9011050
Filing Date: 2015-04-21
Classification: B23G,Y10T

Abstract:
1. A cutting tap comprising a body having an axial forward end and an axial rearward end, the body having a threaded body portion with spiral flutes adjacent the axial forward end, a cylindrical shank portion adjacent the axial rearward end and a central, longitudinal axis, the threaded body portion including a chamfered fluted section and a constant diameter section, the chamfered fluted section extending from the axial forward end and terminating at the constant diameter section, the constant diameter section including a cutting thread, a cutting edge formed at an intersection between the spiral flute and the cutting thread, and a chamfer surface having a chamfer relief extending radially inward from the cutting edge toward a heel of a land, wherein the chamfer surface has an inwardly-inclining convex profile such that an amount of chamfer relief gradually and continuously increases until a maximum value at a point between the cutting edge and the heel, and wherein the chamfer surface extending between the point of the maximum value of the chamfer relief and the heel is directed radially outward so as to form a clearance at the heel of the land that is smaller than the maximum value of the chamfer relief.