Patent ID: 8827606

Claim:
A multi-piece spade drill head for a spade drill, the spade drill comprising an elongate body portion and a cutting portion removably secured to an end of the body portion, the multi-piece spade drill head comprising: at least three insert pieces, each piece including a cutting edge, wherein the at least three insert pieces are configured to be removably secured to the body portion adjacent one another with the cutting edges aligned to abut and form substantially straight, continuous cutting edge regions on an end of the spade drill, the at least three insert pieces comprising a center insert piece and two side insert pieces, wherein the two side insert pieces are configured to be removably secured to the body portion mated with opposite sides of the center insert piece; wherein the center insert piece comprises a longer cutting edge portion and a shorter cutting edge portion, and each of the two side insert pieces comprise a longer cutting edge portion and a shorter cutting edge portion; wherein the aligned cutting edges of adjacent insert pieces form a first interface and a second interface; wherein a first distance measured in a direction perpendicular to an axis of rotation of the drill head from the axis of rotation to the first interface differs from a second distance measured in a direction perpendicular to the axis of rotation from the axis of rotation to the second interface; and wherein at least one of the three insert pieces includes two cutting edges and is configured to be individually indexable and secured to the body portion in two cutting orientations, wherein in each cutting orientation a different cutting edge is aligned with cutting edges of the remaining insert pieces to form the cutting edge on the end of the spade drill when the inserts are removably secured to the body portion of the spade drill.