A downhole tool for use in a downhole drill string is provided. The downhole tool includes a rotor movably coupled within a stator, and a drive shaft movably coupled within a bearing housing. The drive shaft has a first end coupled with the rotor and a second end coupled with a drill bit. Bearing assemblies interfaces engagement between the drive shaft and the bearing housing, including polycrystalline diamond elements, each with an engagement surface, and an opposing engagement surface of a non-superhard metal.

A downhole tool for use in a downhole drill string is provided. The downhole tool includes a rotor movably coupled within a stator, and a drive shaft movably coupled within a bearing housing. The drive shaft has a first end coupled with the rotor and a second end coupled with a drill bit. Bearing assemblies interfaces engagement between the drive shaft and the bearing housing, including polycrystalline diamond elements, each with an engagement surface, and an opposing engagement surface of a non-superhard metal.

A superhard construction comprises a substrate comprising a peripheral surface, an interface surface and a longitudinal axis and a super hard material layer formed over the substrate and having an exposed outer surface forming a working surface, a peripheral surface extending therefrom and an interface surface. One of the interface surface of the substrate or the interface surface of the super hard material layer comprises one or more projections arranged to project from the interface surface, the height of the one or more projections being between around 0.2 mm to around 1.0 mm measured from the lowest point on the interface surface from which the one or more projections extend.

The force modulation system for a drill bit includes a cutter, a holder, a holder retention device, and a first force member. The cutter fits in the holder, and the holder fits in the drill bit. The holder retention device exerts a holder retention force in a first direction. The first force member exerts a first force in a second direction. The second direction is angled offset to the first direction so as that the cutting profile of the force modulation system is now variable in the second direction, according to the first force. There can also be a second force member to exert a second force in the first direction for more variability of the cutting profile in the first direction. The second force member can be made integral with the first force member.

Polycrystalline diamond cutting elements having enhanced thermal stability, drill bits incorporating the same, and methods of making the same are disclosed herein. In one embodiment, a cutting element includes a substrate having a metal carbide and a polycrystalline diamond body bonded to the substrate. The polycrystalline diamond body includes a plurality of diamond grains bonded to adjacent diamond grains by diamond-to-diamond bonds and a plurality of interstitial regions positioned between adjacent diamond grains. At least a portion of the plurality of interstitial regions comprise lead or lead alloy, a catalyst material, metal carbide, or combinations thereof. At least a portion of the plurality of interstitial regions comprise lead or lead alloy that coat portions of the adjacent diamond grains such that the lead or lead alloy reduces contact between the diamond and the catalyst.

A method of making a cutting element includes subjecting a mixture of diamond particles and a carbonate material to high-pressure high-temperature sintering conditions to form a sintered carbonate-polycrystalline diamond body having a diamond matrix of diamond grains bonded together and carbonates residing in the interstitial regions between the diamond grains, the carbonate material having a non-uniform distribution throughout the diamond matrix. The carbonate-polycrystalline diamond body is subjected to a controlled temperature, a controlled pressure condition or a combination thereof, to effect an at least partial decomposition of the carbonate material.

Rotary drill bits may include on or more cutting element assemblies which include a cutter and a mounting system. In one embodiment, the mounting system includes a housing, a first bearing component disposed within the housing, and a second bearing component associated with the cutting element. In certain embodiments, the bearing components may comprise a table of superhard material bonded with a substrate. In one or more embodiments, the bearing components may include bearing surfaces that are arcuate. For example, the bearing surfaces may be substantially spherical (a portion of a sphere). The bearing components may be arranged to act as a radial bearing as well as a thrust bearing for the cutting element, enabling the cutting element to rotate about a longitudinal axis of the cutter, relative to the housing, while also enabling the longitudinal axis of the cutter to be displaced (change angles) relative to the housing.

Rotary drill bits may include on or more cutting element assemblies which include a cutter and a mounting system. In one embodiment, the mounting system includes a housing, a first bearing component disposed within the housing, and a second bearing component associated with the cutting element. In certain embodiments, the bearing components may comprise a table of superhard material bonded with a substrate. In one or more embodiments, the bearing components may include bearing surfaces that are arcuate. For example, the bearing surfaces may be substantially spherical (a portion of a sphere). The bearing components may be arranged to act as a radial bearing as well as a thrust bearing for the cutting element, enabling the cutting element to rotate about a longitudinal axis of the cutter, relative to the housing, while also enabling the longitudinal axis of the cutter to be displaced (change angles) relative to the housing.

A downhole tool for use in a downhole drill string is provided. The downhole tool includes a rotor movably coupled within a stator, and a drive shaft movably coupled within a bearing housing. The drive shaft has a first end coupled with the rotor and a second end coupled with a drill bit. Bearing assemblies interfaces engagement between the drive shaft and the bearing housing, including polycrystalline diamond elements, each with an engagement surface, and an opposing engagement surface of a non-superhard metal.

A downhole tool for use in a downhole drill string is provided. The downhole tool includes a rotor movably coupled within a stator, and a drive shaft movably coupled within a bearing housing. The drive shaft has a first end coupled with the rotor and a second end coupled with a drill bit. Bearing assemblies interfaces engagement between the drive shaft and the bearing housing, including polycrystalline diamond elements, each with an engagement surface, and an opposing engagement surface of a non-superhard metal.