Abstract: A drill bit, and a cutter for a drill bit, are provided, wherein the cutter will encounter the formation with cutting surfaces of differing rake angles to optimize cutting efficiency. In most circumstances, the cooperating cutters will have differing, positive, and negative or neutral rakes. Cutters of differing rakes may be cooperatively paired on a drill bit such that the portion of a formation which is affected by the action of one cutter may be similarly affected by the operation of the other cutter.

Abstract: A non-coring rotary mining tool having a bit body constructed and arranged for rock boring as in roof bolting operations, and including PCD cutter inserts of preselected size mounted at a negative angle and having substantially continuous cutting edges defining a sinusoidal cutting path from the tool axis to the gauge-cutting margins thereof; and a method of drilling rock bores utilizing moderate rotational speeds, reduced axial thrust and delivery of flushing fluids at substantially higher pressures.

Abstract: Self-shaping disk-shaped cutting edge of a drilling tool, comprising an outer diamond-impregnated polycrystalline layer (22) applied onto a tungsten carbide layer (24), each cutting edge being mounted on a support (18) which is integral with the body (12) of the drilling tool. The cutting edge and/or its support (18) have areas (26) of least resistance, such as grooves, which are likely to cause successive fractures, thereby forming an acute relief angle (.alpha.) with the rock to be drilled (28).

Abstract: A diamond drag type drill bit for drilling in an earthen formation consists of a body forming a first cutting end formed from a matrix material and a second open threaded pin end. The first cutting end consists of a multiplicity of substantially radially disposed ridges and flow channels formed by the matrix material. The flow channels intersect a fluid discharge port and radially extend outwardly toward a peripheral edge formed by the cutter end. The ridges contain, along their apical, radially extended edges, a multiplicity of essentially equidistantly spaced diamond cutters having each of their cutting edges formed therein aligned substantially along the apical edge. The space between each diamond cutter contains a metallic filler material aligned along the apical edge that is less hard than either the diamond or the supporting matrix material forming the first cutting end of the drag bit.

Abstract: A rotary mining tool having a steel body adapted to be driven axially and turned in a rotational arc relative to its axis and being provided with a hardened wear surface with a cutting edge adapted for cutting engagement with a work area under the axial thrust of said tool body, the wear surface and cutting edge being constructed and arranged with a negative rake angle and a negative skew angle to position the wear surface for such cutting engagement under substantially total compression to thereby minimize tensile shear forces that would tend to break or crack the hardened wear surface.

Abstract: A tubular drill string element, such as a stabilizer or tool joint, comprises an outer surface having in circumferential direction a ratchetted profile. The ratched profile is preferably oriented such that provides low resistance against right hand rotation but high resistance against left hand rotation of the drill string.

Abstract: A chisel gage insert is disclosed having a larger nose radius at the outer end of the insert crest than at the inner end thereby providing more mass on the portion of the insert that contacts the borehole sidewall. The rounded crest also blends with the convex surfaces of the insert extension so as not to have any non-tangential intersections.

Abstract: The present invention comprises a cutting structure for earth boring drill bits and a bit including at least one such structure comprising a substantially planar array of cutting elements arranged in substantially contiguous mutual proximity, the array incorporating at least one discontinuity therein dividing it into a plurality of sub-arrays.

Abstract: The present invention discloses an apparatus and method for directing drilling fluid to the cutting tip of a downhole drilling bit cutter by one or more flow channels formed in the upper section of the cutter's front surface, thereby maximizing the cleaning and cooling effect of the fluid flow on the actual cutting surface. Another embodiment of the present invention discloses an apparatus and method for helping to peel a rock chip from the face of a downhole drilling bit cutter while simultaneously cleaning and cooling the drill bit cutter cutting tip.