Patent ID: 6315064
Filing Date: 2001-11-13
Classification: E21B

Abstract:
A rotatable cutting bit for penetrating an earth formation, the rotatable cutting bit comprising:an elongate bit body having a forward end and a rearward end, the bit body defining a peripheral surface;the bit body having a first cutting insert attached to the bit body at the axially forward end thereof, the first cutting insert presenting a first leading cutting edge and a first side clearance cutting edge;the first cutting insert being attached to the bit body so that the first side clearance cutting edge radially extends past the peripheral surface of the bit body so as to engage the earth formation;the first leading cutting edge having a radially inward portion and a radially outward portion, and the radially inward portion being disposed at an angle with the respect to the radially outward portion;the first cutting insert includes a top surface and a leading surface, and the leading surface comprising a radially inward surface portion and a radially outward surface portion, and the top surface intersects with the radially inward leading surface portion as to define the radially inward portion of the leading cutting edge, and the top surface intersects with the radially outward leading surface portion so as to define the radially outward portion of the cutting edge; andthe cutting insert further including a bevelled surface, and the leading surface and the beveled surface intersecting so as to form a side clearance cutting edge at the juncture thereof.