Hybrid Rolling Cone Drill Bits and Methods for Manufacturing Same

A rolling cone drill bit for drilling a borehole in earthen formations, the bit comprising:

• a bit body having a bit axis;
• and
• a rolling cone cutter mounted on the bit body and having a cone axis of rotation;
• wherein the cone cutter includes a cone body, a plurality of circumferentially-spaced teeth arranged in a first inner row, and a plurality of inserts disposed in the first inner row, wherein each pair of circumferentially adjacent teeth comprises a leading tooth relative to a direction of cone rotation about the cone axis and a trailing tooth relative to a direction of cone rotation about the cone axis;
• wherein each insert in the first inner row is circumferentially positioned between one of the pairs of circumferentially adjacent teeth, wherein each insert is circumferentially proximal the leading tooth of the corresponding pair of circumferentially adjacent teeth and distal the trailing tooth of the corresponding pair of circumferentially adjacent teeth.

A rolling cone drill bit for drilling a borehole in earthen formations, the bit comprising:

• a bit body having a bit axis;
• and
• a rolling cone cutter mounted on the bit body and having a cone axis of rotation;
• wherein the cone cutter includes a cone body, a plurality of circumferentially-spaced teeth arranged in a first inner row, and a plurality of circumferentially-spaced inserts disposed in the first inner row, wherein each pair of circumferentially adjacent teeth comprises a leading tooth relative to a direction of cone rotation about the cone axis and a trailing tooth relative to a direction of cone rotation about the cone axis;
• wherein each tooth in the first inner row has a convex leading flanking surface relative to the direction of cone rotation, a concave trailing flanking surface relative to the direction of cone rotation, and a curved chisel crest disposed at the intersection of the leading flanking surface and the trailing flanking surface.