A down-the-hole drill hammer is provided that includes a housing, a drill bit proximate a distal end of the housing, and a roller bearing assembly. The roller bearing assembly circumscribes the drill bit. The roller bearing assembly includes a race and a plurality of rollers. The plurality of rollers are operatively engaged with the race.

A down-the-hole drill hammer is provided that includes a housing, a drill bit proximate a distal end of the housing, and a roller bearing assembly. The roller bearing assembly circumscribes the drill bit. The roller bearing assembly includes a race and a plurality of rollers. The plurality of rollers are operatively engaged with the race.

A roller reamer for downhole operations in boreholes, such as are drilled for oil and/or natural gas production, or as injection wells. An elongated main body has preferably three circumferentially spaced pockets. A roller assembly is preferably disposed in each pockets, the roller rotating in roller blocks at each end of the roller disposed within the roller blocks. Mating locking profiles, such as dovetails, lock the roller blocks within the pockets, as the roller blocks are moved longitudinally into the locking profiles, preventing any radially outward movement of the roller assembly. The roller assembly is prevented from longitudinal movement within the pockets by lock blocks also positioned within the pockets.

A roller reamer for downhole operations in boreholes, such as are drilled for oil and/or natural gas production, or as injection wells. An elongated main body has preferably three circumferentially spaced pockets. A roller assembly is preferably disposed in each pockets, the roller rotating in roller blocks at each end of the roller disposed within the roller blocks. Mating locking profiles, such as dovetails, lock the roller blocks within the pockets, as the roller blocks are moved longitudinally into the locking profiles, preventing any radially outward movement of the roller assembly. The roller assembly is prevented from longitudinal movement within the pockets by lock blocks also positioned within the pockets.

An earth-boring drill bit includes a bit body including a central shaft having a longitudinal axis, an annular cutter body disposed around, and rotatable relative to, the central shaft, at least one gear assembly operatively coupling the annular cutter body to the central shaft, a first cutter disposed on the central shaft at a first distance from the longitudinal axis, and a second cutter disposed on the annular cutter body at a second, greater distance from the longitudinal axis. Methods of fabricating earth-boring drill bits include rotatably coupling at least one annular cutter body to a central shaft, the at least one annular cutter body and the central shaft being concentric.

An earth-boring drill bit includes a bit body including a central shaft having a longitudinal axis, an annular cutter body disposed around, and rotatable relative to, the central shaft, at least one gear assembly operatively coupling the annular cutter body to the central shaft, a first cutter disposed on the central shaft at a first distance from the longitudinal axis, and a second cutter disposed on the annular cutter body at a second, greater distance from the longitudinal axis. Methods of fabricating earth-boring drill bits include rotatably coupling at least one annular cutter body to a central shaft, the at least one annular cutter body and the central shaft being concentric.

A disclosed example embodiment includes a drill bit used to form wellbores in subterranean formations. The drill bit includes a drill bit body for coupling to a lower end of a drill string. The drill bit body includes at least one support arm having an inwardly extending journal with a journal bearing having at least one radially reduced pocket extending at least partially circumferentially around the journal bearing including a load side of the journal bearing. At least one rotary cutter assembly is rotatably mounted to the journal. A plurality of cutting elements is disposed on the at least one rotary cutter assembly. At least two independent hardmetal pads are positioned within the at least one radially reduced pocket such that the hardmetal pads have a gap disposed therebetween.

A disclosed example embodiment includes a drill bit used to form wellbores in subterranean formations. The drill bit includes a drill bit body for coupling to a lower end of a drill string. The drill bit body includes at least one support arm having an inwardly extending journal with a journal bearing having at least one radially reduced pocket extending at least partially circumferentially around the journal bearing including a load side of the journal bearing. At least one rotary cutter assembly is rotatably mounted to the journal. A plurality of cutting elements is disposed on the at least one rotary cutter assembly. At least two independent hardmetal pads are positioned within the at least one radially reduced pocket such that the hardmetal pads have a gap disposed therebetween.

A rotary drill tool for cutting rock includes at least one journal leg mounting a spindle and a respective rotary cone cutter. The spindle includes a plurality of fluid distribution passageways arranged to provide a supply of a cooling and cleaning fluid to the bearing assembly. Vent holes are provided through the cutter to allow an exhaust flow of fluid and an annular seal is provided at a base region of the spindle to maintain a positive fluid pressure within the cutter cavity to prevent dust and dirt ingress.

A rotary drill tool for cutting rock includes at least one journal leg mounting a spindle and a respective rotary cone cutter. The spindle includes a plurality of fluid distribution passageways arranged to provide a supply of a cooling and cleaning fluid to the bearing assembly. Vent holes are provided through the cutter to allow an exhaust flow of fluid and an annular seal is provided at a base region of the spindle to maintain a positive fluid pressure within the cutter cavity to prevent dust and dirt ingress.