Smith International, Inc.

George Fyfe

Kenneth W Jones

A diamond insert for a rotary drag bit consists of an insert stud body that forms a first base end and a second cutter end. The cutter end of the insert is formed in a convex or spherical shape of polycrystalline diamond material. The convex layer of diamond is oriented relative to an axis of the stud body with a negative rake angle from 0.degree. to about 45.degree. inclusive.

Convex shaped diamond cutting elements

A mechanism is disclosed for rock bits whereby cutting elements, rotatably mounted to fixtures with journals, are constantly forced to rotate or precess by the interaction of the earth formation and the cutter. The cutters are fixed in skewed or offset positions on a cutting face of a rotary drill bit head. These cutting elements act as drag or shear cutters when they are operated in an earth formation.

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Houston, TX, United States of America

George Fyfe