Abstract: A rotary drag bit carrying PDC cutters and elongated bearing elements associated with at least some of the PDC cutters on the bit face thereof Lateral positioning and angular positioning of the elongated bearing elements are adjusted so that all portions of an elongated bearing element travel substantially completely within a tubular clearance volume defined by the path through the formation being drilled by a PDC cutter with which that elongated bearing element is associated, the associated PDC cutter being positioned at about the same radius from the bit centerline as the elongated bearing element. A method of drilling and a method of drill bit design are also disclosed.

Abstract: A rotary drag bit carrying PDC cutters and elongated bearing elements associated with at least some of the PDC cutters on the bit face. Lateral positioning and angular positioning of the elongated bearing elements are adjusted so that all portions of a elongated bearing element travel substantially completely within a tubular clearance volume defined by the path through the formation being drilled by a PDC cutter with which that elongated bearing element is associated, the associated PDC cutter being positioned at about the same radius from the bit centerline as the elongated bearing element. A method of drilling and a method of drill bit design are also disclosed.

Abstract: A cutting element substrate for use with an earth-boring drill bit. The substrate includes a base, or outer shell, with a cavity opening to an end thereof. The base is fabricated from an erosion-resistant and abrasion-resistant material. A core that is configured substantially complementarily to the cavity is disposed within the cavity. The core base is fabricated from a material that is more ductile than the material of the base. The core and base each includes a cutting end to which a superabrasive cutting table, such as a polycrystalline diamond compact, may be secured. The substrate may be secured within a corresponding receptacle of a bit body in order to secure a superabrasive cutting table to the bit body in a desired orientation. The present invention also includes methods of fabricating the cutting element substrate.

Abstract: A rock bit has a body and three cutters that include generally conical surfaces, at least one of which contains an outermost, circumferential row of heel teeth that dislodge cuttings from the borehole wall and bottom. The heel teeth form a corner with the borehole wall with successive contact points defined by the path of outer edges of the heel teeth while rotating into, and prescribing, the corner as it spirals downwardly during drilling. The rotational axis of the cutter is offset from the geometric centerline or intended rotational axis of the bit. Stabilizing pads extend outwardly from the body, each concluding in a surface that contains a low-friction, wear-resistant surface that engage the wall of the borehole. The center of each surface is located directly across from the contact point of an opposed cutter.

Abstract: An earth-boring bit has a bit body that is threaded at one end for connection into a drill string. At least one cantilevered bearing shaft depends inwardly and downwardly from the bit body. A cutter is mounted for rotation on each bearing shaft and includes a plurality of cutting elements arranged in generally circumferential rows. At least one wear-resistant element is secured to the bit body between the lower end of the bit body and the threaded end, the wear-resistant element being elongate or generally oblong in cross-section.