Patent ID: 7516686

Claim:
A method for making a twist drill comprising: forming a cylindrical blank, having a longitudinal axis and two transverse axes extending perpendicular to one another and to the longitudinal axis; forming at least one flute in the cylindrical blank, the at least one flute including a ridge disposed therein for prompting breakage of chips formed during use of the drill, the at least one flute extending from a point region of the cylindrical blank to a shank region of the cylindrical blank; forming at least one land in the cylindrical blank, the at least one land extending along the blank adjacent to the at least one flute; grinding the point region of the cylindrical blank to a contact angle; grinding a brad and spur configuration onto the point region; forming an axial relief surface on the at least one land, by aligning the blank along a first axis of a three coordinate axis system, inclining the blank a selected angle away from the first axis while maintaining the blank within a plane defined by the first axis and another axis of the three coordinate system, and then inclining the blank a selected angle away from the plane defined by the first axis and another axis of the three coordinate system; and presenting the blank to a planar grinding surface disposed perpendicular to the first axis of the three coordinate system.