Patent ID: 7147414

Claim:
A drill insert comprising: a drill insert body comprising a first end, a second end, a pair of connection surfaces formed generally parallel to each other on opposite sides of the drill insert body, and a pair of margins extending from the first end to the second end; wherein the second end comprises a first cutting portion formed on a first insert diameter and a second cutting portion formed on a second insert diameter generally corresponding to the outside diameter of the drill insert body, wherein the first cutting portion comprises at least two cutting edges forming a primary included angle and wherein the cutting edges of the first cutting portion extend from opposite ends of a chisel point to the first insert diameter, wherein the second cutting portion comprises at least two cutting edges forming a secondary angle, wherein the cutting edges of the second cutting portion are adjacent to and form a continuous cutting edge with the cutting edges of the first cutting portion, and wherein the cutting edges of the second cutting portion extend from the first insert diameter to the second insert diameter; a plurality of grooves formed in the connection surfaces, each groove adjacent each cutting edge, each groove having a groove trough parallel to the corresponding adjacent cutting edge, the grooves of the second cutting portion being formed at a constant depth at least along the length of the cutting edges of the second cutting portion, the grooves of the first cutting portion being formed at a depth increasing from the first insert diameter toward the chisel point.