Importance

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Abstract

Drill bit cutters and drill bits equipped with the cutters. The cutter is mounted on a bit to present the formation with a radiused, curving, side wall cutting face that is concave in one dimension and convex in another dimension. In a preferred form, the cutting face is in the form of a portion of a surface of revolution generated by an arc segment that is concave relative to the axis of revolution. The cutting face is formed on a layer of polycrystalline diamond disposed on a substrate of tungsten carbide. In another side wall cutter arrangement, a standard cylindrical cutter with a diamond cap is mounted to present the curved cylindrical side of the cap to the formation. Curved side wall cutting faces cut more efficiently than the usual flat end face of conventionally mounted cutters. A major portion of the diamond volume in a side mounted cutter trails the point of cutting face engagement with the formation to provide impact resistance and an increased diamond wear area. The radiused face cutter may be mounted in any orientation on the bit. When mounted conventionally, such that the axis of the cutter is inclined away from the bit and into the direction of bit rotation, the cutter end surface rather than the side wall cuts the formation. In this orientation, the rake of the cutter may be increased to place a second cutting surface into engagement with the formation to provide two cutting surfaces.

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First Claim