Patent ID: 6637987
Filing Date: 2003-10-28
Classification: B23B,B23C,Y10T

Abstract:
A drill bit for axial cutting and side cutting, the drill bit comprising:a generally cylindrical elongate body having a bit diameter which includes a frontmost drilling end for axial cutting, a cutting section extending from the drilling end for side cutting, and a shank extending from the cutting section, wherein the cutting section is helically cut at a helix angle of substantially 15Â°Â±2Â° to form one pair of diametrically opposite helical flutes having outermost edges sharpened to form respective cutting edges, around a solid central core having a core diameter substantially directly proportional to the bit diameter, and the length of the cutting edges in the axial direction of the drill bit body is related to other drill dimensions as: Cutting Edge=Bit DiameterÃ—&pgr;Ã—Cc/Tan(Helix Angle), Cc being a constant ranging substantially from 0.85 to 0.90.