Patent ID: 7237986
Filing Date: 2007-07-03
Classification: B23B,Y10T

Abstract:
1. A drill bit comprising: a shank portion; a flute portion, said flute portion defining a helix angle; and a tip, said tip including a primary cutting edge extending to an outer periphery of the drill bit, said primary cutting edge defined by a rake face and a clearance face, said rake face defining a rake angle, said rake angle being different from said helix angle at said tip, an included angle is defined between said clearance face and said rake face, said included angle being between about 25° to about 45°; and an egress surface is between said rake surface and said flute at said tip such that said egress surface projects outward from said rake face so that chips cut from a workpiece contact said egress surface to provide a smooth transition into the flute portion.