Matrix diamond drag bit with PCD cylindrical cutters

A process of forming a matrix type diamond drag bit cutter head having a multiplicity of cylindrically shaped polycrystalline diamond inserts strategically positioned and metallurgically secured to a drag bit face comprising the steps of:

• forming a female mold of heat resisting material,
• milling a multiplicity of first cylindrically shaped insert channels in said mold, said channels being formed in a direction of rotation of said drag bit and at an angle to an earthen formation such that a negative rake angle is established with respect to a cutting face of said cylindrically shaped polycrystalline diamond insert,
• milling a second non-parallel channel substantially axially aligned with and superimposed over said first channel but at a shallower angle and at a depth less than the depth of said first cylindrically shaped channel, said second channel provides a pocket surrounding said first channel thus providing a matrix filled support for said cylindrically shaped insert,
• securing a heat resistant cylindrically shaped stud in each of said first cylindrically shaped insert channels,
• inserting said matrix material in powder form in said female mold,
• heating said matrix material in said mold in a furnace thereby forming said cutter head,
• removing said heat resistant studs from said first cylindrically shaped insert channels;
• and
• bonding metallurgically, said cylindrically shaped polycrystalline diamond inserts into each of said first insert channels, said inserts having additional support provided by the matrix filled second channel at a different angle and a lesser depth surrounding said insert.