Patent ID: 8714890

Claim:
A drill bit comprising: a drill bit body having a central axis; a first cutting flute having a first cutting edge disposed on the drill bit body at a first radial distance from the central axis as measured within a first plane normal to the central axis; a second cutting flute having a second cutting edge disposed on the drill bit body at a second radial distance from the central axis as measured from within a second plane normal to the central axis, the first radial distance being less than the second radial distance; the first and second cutting edges each having a length extending along a combined direction of substantially perpendicular to the central axis and helically along the drill bit body; the length of the first cutting edge being longer than the length of the second cutting edge such that during orbital drilling, the first cutting edge removes a majority of material being machined; and the first cutting edge is made of polycrystalline diamond, and the second cutting edge is made of cubic boron nitride.