Patent ID: 8408850

Claim:
A drill for making a hole within a workpiece, wherein the drill is comprised of: a) a body extending along a longitudinal axis; b) at least one flute extending along the body; and c) a drill point extending from the end of the body, wherein the drill point has a periphery and end segments about the longitudinal axis; wherein each end segment is comprised of: 1) a chisel edge extending outwardly from the longitudinal axis to a chisel edge outer end; 2) a primary cutting edge extending inwardly from the periphery; 3) a secondary cutting edge extending outwardly from the chisel edge outer end, wherein the secondary cutting edge has a positive or neutral axial rake angle; and 4) a tertiary cutting edge connecting the primary cutting edge with the secondary cutting edge, wherein the tertiary cutting edge has a negative axial rake angle, and when viewed from the side, the tertiary cutting edge has an axial arc, wherein the axial rake angle along the axial arc has a variation along the axial arc of approximately 6 to 9 degrees.