Method of manufacturing cutter elements for drill bits

In a method of bonding a composite compact to a mounting stud of the type used to mount the compact as a cutter element in a drill bit where the composite compact has an exposed, abrasive diamond surface which has previously been bonded to a substrate portion, the improvement comprising the steps of:

• coating the exposed, diamond surface of said composite compact with a thin, metal layer, said metal being selected from the group consisting of I-B, II-B, IV-B, V-B, VI-B, VII-B, and VIII, elements of the periodic talble of chemical elements and alloys thereof;
• grinding said coated, diamond surface of said composite compact to form a smoothly ground surface;
• providing a brazing filler between said compact substrate portion and said mounting stud;
• and
• contacting said smoothly ground surface of said composite compact with a heat sink while brazing said substrate portion of said composite compact to said mounting stud.

In a method of bonding a composite compact to a mounting stud of the type used to mount the compact as a cutter element in a drill bit where the composite compact has an exposed, abrasive diamond surface which has previously been bonded to a substrate portion, the method comprising the steps of:

• coating the exposed, diamond surface of said composite compact with a thin, metal layer, said layer being selected from the group consisting of group I-B, II-B, IV-B, V-B, VI-B, VII-B, and VIII, elements of the periodic table of chemical elements and alloys thereof;
• grinding said coated, diamond surface of said composite compact to a depth sufficient to form a smoothly ground surface;
• providing a brazing filler between said compact substrate portion and said mounting stud;
• and
• contacting said smoothly ground surface of said composite compact with a heat sink while brazing said substrate portion of said composite compact to said mounting stud at a temperature above the thermal degradation temperature of said diamond surface.

A method of fabricating a drill bit having a plurality of cutter elements carried thereon, said cutter elements being mounted on said drill bit by mounting studs, comprising the steps of:

• providing a plurality of composite compacts, each of said compacts having an exposed abrasive diamond surface which has previously been bonded to a carbide substrate portion;
• coating the exposed, diamond surface of said composite compact with a thin, metal layer, said metal comprising any metal which will form a compatible coating with said composite compact and which is relatively easier to grind away than the diamond surface;
• grinding the metal-coated surface of said composite compact to a depth slightly less than the depth of said abrasive diamond surface to form a smoothly ground surface for said compact;
• providing a brazing filler between said compact substrate portion and said mounting stud;
• and
• contacting said smoothly ground surface of said compact with a heat sink while brazing said carbide substrate portion of said composite compact to said mounting stud;
• and
• affixing the mounting stud end of each such cutter element so prepared to a receiving area provided on said drill bit.