Patent ID: 8070397

Claim:
A drill bit comprising: a shank defining an axis of rotation; a screw tip having a periphery arranged along said axis of rotation; a cutting head attached to said shank, said cutting head comprising an annular wall positioned about the axis of rotation and at least one tooth arranged on the distal end of the annular wall and a slot formed in the cutting head for releasably retaining a cutting blade, the slot formed by a front wall and a back wall, the front wall extending from adjacent the screw tip to the annular wall and defining a leading face, the front wall terminating short of the distal end of the annular wall, a first hole being formed in the front wall for receiving a fastener, and the back wall extending from the annular wall to a line extending through the center of the cutting head arranged perpendicular to the cutting blade, the back wall extending to the distal end of the annular wall, the back wall comprising a threaded hole for threadably receiving the fastener, the slot being formed at an acute angle relative to the axis of rotation; and the cutting blade being removably mounted in the slot and comprising a first portion that is closely received in the slot and that comprises a second hole for receiving the fastener and a second portion that comprises a cutting edge, the second portion extending from the slot where the cutting blade includes a recess for receiving the screw tip such that the cutting edge extends beyond the periphery of the screw tip, said second portion comprising a second leading face that is disposed such that the second leading face of the second portion is coplanar with the leading face of the front wall.