A rock bit tip (120) comprising a mounting portion (122), an end portion (11) converging from a top end of the mounting portion to form a work surface and at least one recess (125) in a bottom (124) of the mounting portion, the recess extending towards said end portion, wherein there are more than one recess. The invention further relates to a rock bit.

Disclosed herein is a method for designing a roller cone drill bit, comprising simulating the bit drilling through an earth formation wherein the simulating comprises determining an axial force on a cutting element, based on a means for determining an axial force, determining an axial force on the roller cones, based on the axial forces on the cutting elements, and angularly rotating the bit; adjusting at least one design parameter of the bit; repeating the simulating the bit drilling; and comparing a distribution of axial forces among the roller cones prior to the adjusting the at least one design parameter with a distribution of axial forces among the roller cones after adjusting the at least one design parameter.

Disclosed herein is a method for determining a drilling parameter of each one of a plurality of roller cones on a roller cone drill bit during drilling, comprising: calculating, from a geometry of cutting elements on each of the roller cones and an earth formation being drilled by the drill bit, the drilling parameter acting on each of the cutting elements; incrementally rotating the bit and recalculating the drilling parameter acting on each of the cutting elements; repeating the incrementally rotating and recalculating for a selected number of incremental rotations; and combining the drilling parameter acting on the cutting elements on each one of the roller cones.

Disclosed herein is a method of designing a roller cone bit, comprising the steps of:

• calculating the curved trajectory of a non-axisymmetric tooth through formation material at the cutting face, as the bit and cones rotate;
• calculating a straight line approximation to said curved trajectory; and
• orienting said tooth with respect to said approximation, and not with respect to said curved trajectory.

Disclosed herein is a method for optimising drilling performance of a roller cone drill bit, comprising simulating drilling with the bit in a selected earth formation to determine at least one drilling performance parameter, adjusting, an orientation of at least one non-axisymmetric cutting element on the bit, repeating the simulating the drilling and determining the at least one performance parameter, and repeating the adjusting and simulating the drilling until the at least one performance parameter is determined to be at an optimum value.

A rolling cutter drill bit comprises a bit body (12) adapted for rotation about a longitudinal axis (8), a plurality of extending legs (14), and a cantilevered bearing spindle (16) formed on each leg (14), a plurality of rolling cone cutters (17, 18, 19) being rotatably mounted upon the bearing spindles (16) with the cone apices (15) adjacent to the longitudinal axis (8) of the bit, a plurality of cutting inserts (20) being secured in the rolling cone cutters (17, 18, 19), and being arranged in a plurality of rows (50, 52, 54), at least two of the rolling cone cutters (17, 18, 19) being intermeshing cutters, arranged such that they have intermeshing rows of cutting inserts (20), wherein at least one of the intermeshing cutters (17, 18, 19) has a groove (72, 74, 76, 78) arranged to register with one of the rows (54) of cutting inserts (20) of another of the intermeshing cutters (17, 18, 19), and wherein the groove (72, 74, 76, 78) contains a plurality of generally flat top bearing inserts (88).