Abstract: A hybrid earth-boring bit comprising a bit body having a central axis, at least one, preferably three fixed blades, depending downwardly from the bit body, each fixed blade having a leading edge, and at least one rolling cutter, preferably three rolling cutters, mounted for rotation on the bit body. A rolling cutter is located between two fixed blades.

Abstract: A hybrid earth-boring bit comprising a bit body having a central axis, at least one, preferably three fixed blades, depending downwardly from the bit body, each fixed blade having a leading edge, and at least one rolling cutter, preferably three rolling cutters, mounted for rotation on the bit body. A rolling cutter is located between two fixed blades.

Abstract: A hybrid earth-boring bit comprising a bit body having a central axis, at least one, preferably three fixed blades, depending downwardly from the bit body, each fixed blade having a leading edge, and at least one rolling cutter, preferably three rolling cutters, mounted for rotation on the bit body. A rolling cutter is located between two fixed blades.

Abstract: A method of improving the service life of a drill bit comprises creating a weldment between load bearing portions of the drill bit where the weldment has a preselected root gap greater than about 25 mils and a preselected root face greater than about 25 mils, and where the weldment has a material property greater than the materials being joined.

Abstract: A bit body is configured at its upper extent for connection into a drillstring. At least one fixed blade extends downwardly from the bit body, and has a radially outermost gage surface. A plurality of fixed cutting elements is secured to the fixed blade, preferably in a row at its rotationally leading edge. At least one bit leg is secured to the bit body and a rolling cutter is mounted for rotation on the bit leg. At least one stabilizer pad is disposed between the bit leg and the fixed blade, the stabilizer pad extending radially outward to substantially the gage surface. The radially outermost gage surface of each blade can extend axially downward parallel to the bit axis or angled (non-parallel), spirally or helically, relative to the bit axis.

Abstract: A method of improving the service life of a drill bit comprises creating a weldment between load bearing portions of the drill bit where the weldment has a preselected root gap greater than about 25 mils and a preselected root face greater than about 25 mils, and where the weldment has a material property greater than the materials being joined.

Abstract: An earth boring drill bit designed for a specific performance, within a finished product tolerance, using components built to a looser manufacturing tolerance. The bit may be assembled by selecting a leg from a plurality of pre-manufactured legs; selecting a bit body from a plurality of pre-manufactured bit bodies, the bit body having a slot for receiving the leg; placing the leg within the slot; and fixing the leg within the slot within the finished product tolerance by placing one or more shims between the leg and the slot. The shims may be used to adjust an axial position, a radial position, and/or a circumferential position of the leg with respect to the slot. The leg and the bit body may be selected, or produced, to ensure the bit will not meet the specification, given the manufacturing tolerance, without the shims.

Abstract: A hybrid earth-boring bit comprising a bit body having a central axis, at least one, preferably three fixed blades, depending downwardly from the bit body, each fixed blade having a leading edge, and at least one rolling cutter, preferably three rolling cutters, mounted for rotation on the bit body. A rolling cutter is located between two fixed blades.

Abstract: A bit body is configured at its upper extent for connection into a drillstring. At least one fixed blade extends downwardly from the bit body, and has a radially outermost gage surface. A plurality of fixed cutting elements is secured to the fixed blade, preferably in a row at its rotationally leading edge. At least one bit leg is secured to the bit body and a rolling cutter is mounted for rotation on the bit leg. At least one stabilizer pad is disposed between the bit leg and the fixed blade, the stabilizer pad extending radially outward to substantially the gage surface. The radially outermost gage surface of each blade can extend axially downward parallel to the bit axis or angled (non-parallel), spirally or helically, relative to the bit axis.

Abstract: A hybrid earth-boring bit comprising a bit body having a central axis, at least one, preferably three fixed blades, depending downwardly from the bit body, each fixed blade having a leading edge, and at least one rolling cutter, preferably three rolling cutters, mounted for rotation on the bit body. A rolling cutter is located between two fixed blades.

Abstract: A bit body is configured at its upper extent for connection into a drillstring. At least one fixed blade extends downwardly from the bit body, and has a radially outermost gage surface. A plurality of fixed cutting elements is secured to the fixed blade, preferably in a row at its rotationally leading edge. At least one bit leg is secured to the bit body and a rolling cutter is mounted for rotation on the bit leg. At least one stabilizer pad is disposed between the bit leg and the fixed blade, the stabilizer pad extending radially outward to substantially the gage surface. The radially outermost gage surface of each blade can extend axially downward parallel to the bit axis or angled (non-parallel), spirally or helically, relative to the bit axis.

Abstract: An earth boring drill bit designed for a specific performance, within a finished product tolerance, using components built to a looser manufacturing tolerance. The bit may be assembled by selecting a leg from a plurality of pre-manufactured legs; selecting a bit body from a plurality of pre-manufactured bit bodies, the bit body having a slot for receiving the leg; placing the leg within the slot; and fixing the leg within the slot within the finished product tolerance by placing one or more shims between the leg and the slot. The shims may be used to adjust an axial position, a radial position, and/or a circumferential position of the leg with respect to the slot. The leg and the bit body may be selected, or produced, to ensure the bit will not meet the specification, given the manufacturing tolerance, without the shims.

Abstract: A bit body is configured at its upper extent for connection into a drillstring. At least one fixed blade extends downwardly from the bit body, and has a radially outermost gage surface. A plurality of fixed cutting elements is secured to the fixed blade, preferably in a row at its rotationally leading edge. At least one bit leg is secured to the bit body and a rolling cutter is mounted for rotation on the bit leg. At least one stabilizer pad is disposed between the bit leg and the fixed blade, the stabilizer pad extending radially outward to substantially the gage surface. The radially outermost gage surface of each blade can extend axially downward parallel to the bit axis or angled (non-parallel), spirally or helically, relative to the bit axis.

Abstract: A roller cone drill bit having a bit body with at least one support arm extending from the bit body. Each support arm may have an associated spindle extending inwardly. A respective cone assembly may be rotatably disposed on each spindle. At least one diverter plug may be disposed in a hole formed in each support arm. A void space may be formed between one end of each diverter plug and the bottom of the associated hole. At least one fluid flow passageway may extend from the surface of the associated support arm to the void space to allow communication of fluid containing debris with the void space. Rotating action of the roller cone drill bit and associated cone assemblies may force packing of debris into the void space which results in biasing the diverter plug outwardly from the associated hole to contact adjacent portions of the associated cone assembly.

Abstract: A hybrid earth-boring bit comprising a bit body having a central axis, at least one, preferably three fixed blades, depending downwardly from the bit body, each fixed blade having a leading edge, and at least one rolling cutter, preferably three rolling cutters, mounted for rotation on the bit body. A rolling cutter is located between two fixed blades.

Abstract: A roller cone drill bit having a bit body with at least one support arm extending therefrom. Each support arm may have an interior surface and an exterior surface with an associated spindle extending inwardly from the interior surface. A respective cone assembly may be rotatably disposed on each spindle. A gap may be formed between interior portions of each cone assembly and exterior portions of the associated spindle with a fluid seal disposed in the gap to block fluid flow therethrough. Each cone assembly may include a generally circular backface disposed adjacent to the interior surface of the associated support arm. At least one fluid passageway may extend through each support arm to allow communication of fluid from the interior surface to an exterior surface of the support arm. A debris diverter insert having a generally hollow bore may be disposed within each fluid passageway.

Abstract: A roller cone drill bit having a bit body with at least one support arm extending from the bit body. Each support arm may have an interior surface and exterior surface with an associated spindle extending from the interior surface. A respective cone assembly may be rotatably disposed on each spindle. A gap formed between interior portions of each cone assembly and exterior portions of the associated spindle with a fluid seal disposed in the gap to block fluid flow therethrough. Each cone assembly includes a generally circular back surface disposed adjacent to the interior surface of the associated support arm. A flow diverter groove formed in the interior surface of each support arm spaced from the associated spindle. Each diverter groove having a variable geometry to enhance the flow of fluid containing downhole debris away from the associated real assembly, and each diverter groove having a variable geometry.

Abstract: A roller cone drill bit having a bit body with at least one support arm extending therefrom. Each support arm may have an interior surface and an exterior surface with an associated spindle extending inwardly from the interior surface. A respective cone assembly may be rotatably disposed on each spindle. A gap may be formed between interior portions of each cone assembly and exterior portions of the associated spindle with a fluid seal disposed in the gap to block fluid flow therethrough. Each cone assembly may include a generally circular backface disposed adjacent to the interior surface of the associated support arm. At least one fluid passageway may extend through each support arm to allow communication of fluid from the interior surface to an exterior surface of the support arm. A debris diverter insert having a generally hollow bore may be disposed within each fluid passageway.

Abstract: A roller cone drill bit having a bit body with at least one support arm extending from the bit body. Each support arm may have an associated spindle extending inwardly. A respective cone assembly may be rotatably disposed on each spindle. At least one diverter plug may be disposed in a hole formed in each support arm. A void space may be formed between one end of each diverter plug and the bottom of the associated hole. At least one fluid flow passageway may extend from the surface of the associated support arm to the void space to allow communication of fluid containing debris with the void space. Rotating action of the roller cone drill bit and associated cone assemblies may force packing of debris into the void space which results in biasing the diverter plug outwardly from the associated hole to contact adjacent portions of the associated cone assembly.

Abstract: A roller-cone rock bit in which the compensation reservoir is integrated with a hydrostatically-asymmetric seal, such as a V-seal, which provides pressure relief. This seal not only relieves overpressure during filling, and when the grease thermally expands as the bit first goes downhole, but also compensates transient overpressures during operation.