Patent ID: 8573331

Claim:
A rotary drilling apparatus, comprising; the drill bit comprising a bit body intermediate a shank and a working surface; the working surface comprising outer cutting elements with a carbide substrate bonded to a diamond working end with a pointed geometry, and the diamond working end comprising a 0.075 to 0.110 inch apex radius; the outer cutting elements are pointed in opposing directions relative to another; the outer cutting elements have an axis that forms an angle of 90 to 180 degrees with the axis of the bit body; a central cutting element is positioned intermediate the opposing outer cutting elements and substantially coaxial with the bit body, the central cutting element also comprises the diamond working end comprising a 0.075 to 0.110 inch apex radius; the central cutting element is configured to stabilize the drill bit as the outer cutting elements rotate about the central axis of the bit body; wherein at an interface between the diamond and carbide substrate, the substrate comprises a tapered surface starting from a cylindrical rim of the substrate and ending at an elevated central region formed in the substrate.