layer having a center and a periphery forming a cutting edge is integrally formed on the substrate application_number US 8248705 A description the shape of the carbide support in fig1 and 2 is unique in that it contains 2 distinctive faces of support for the abrasive material each face being disposed at an angle relative to the horizontal so as to optimized minimize radial stress and axial stress to that end a cutter 10 is formed from a lower support 12 and an upper abrasive layer 14 see fig2 support 12 has a central inner face 16 that extends outwardly and downwardly from an apex or center 18 surrounding face 18 is an outer annular face 20 that extends outwardly and downwardly from the outer periphery of face 16 a slight ledge 22 surmounts the outer periphery of annular face 20 superimposed on inner face 16 can be sawtooth annuli and troughs such as are proposed in u s pat no 6 315 652 in order to optimize minimize radial stress outer annular face 20 should slope downwardly from the horizontal at an angle of between about 20 u00b0 and about 75 u00b0 with about 45 u00b0 being preferred in order to optimize minimize axial stress inner face 16 should slope downwardly from the horizontal at an angle of between about 5 u2032 and about 15.