US Patent 7726420 Cutter having shaped working surface with varying edge chamfer

A cutter for a drill bit used for drilling wells in a geological formation includes an ultra hard working surface and a chamfer along an edge of the working surface, wherein the chamfer has a varied geometry along the edge. The average geometry of the chamfer varies with cutting depth. A depression in the shaped working surface is oriented with the varied chamfer and facilitates forming the varied chamfer. A non-planar interface has depressions oriented with depressions in the shaped working surface to provide support to loads on the working surface of the cutter when used.