Patent ID: 7798257

Claim:
A cutter for an earth boring drag bit, the cutter comprising: an ultrahard material layer bonded to a substrate, the ultrahard material layer comprising a peripheral side surface and a shaped working surface, said working surface intersecting said peripheral side surface, wherein a peripheral edge is defined by said intersection, said peripheral edge forming at least a cutting edge, wherein the shaped working surface comprises an axially asymmetrical curved surface, the axially asymmetrical curved surface comprising a smoothly continuous compound curve, wherein the smoothly continuous compound curve comprises a continuously curving convex portion and concave portions extending from opposite sides of said convex portion, wherein any first point on the peripheral edge intersected by an axial plane extending across the convex portion and the concave portions and through a central axis of said ultrahard material layer is at a level as measured axially from a second point on the convex portion that is at a distance from said first point no less than all levels of the concave portions along said plane as measured axially from said second point.