Earth-boring tools may comprise rotatable cutting elements rotatably connected to protruding journals, which may be at least partially located within inner bores extending through the rotatable cutting elements. A rotationally leading end of one of the protruding journals may not extend beyond a cutting face of its associated rotatable cutting element. Alternatively, a protruding journal may comprise a chip breaker protruding from a cutting face of a rotatable cutting element. Methods of removing an earth formation may include directing cuttings forward, away from a cutting face of a rotatable cutting element when the cuttings reach an inner bore of the rotatable cutting element, and rotating the rotatable cutting element around a protruding journal at least partially located in the inner bore.

A mill-drill cutter for an earth boring bit includes a cutting structure secured to a substrate. The cutting structure has a drilling edge, and the substrate has a milling edge. The substrate is configured to be received in a cutter pocket of the earth boring bit. The drilling edge of the cutting structure is disposed radially internal to the milling edge of the substrate.

A mill-drill cutter for an earth boring bit includes a cutting structure secured to a substrate. The cutting structure has a drilling edge, and the substrate has a milling edge. The substrate is configured to be received in a cutter pocket of the earth boring bit. The drilling edge of the cutting structure is disposed radially internal to the milling edge of the substrate.

An instrumented cutter including a polycrystalline diamond table bonded to a substrate with a sensor, for monitoring the condition of the polycrystalline compact diamond table, embedded in the substrate. Further the instrumented cutter includes a wireless transmitter equipped with a power supply to power to the wireless transmitter.

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.

A super hard polycrystalline construction comprises a body of polycrystalline super hard material, said body having an exposed working surface, a substrate attached to the body of polycrystalline super hard material along an interface and a plurality of apertures or channels. One or more of said apertures or channels extend(s) from the exposed working surface of the body into the substrate.

A super hard polycrystalline construction comprises a body of polycrystalline super hard material, said body having an exposed working surface, a substrate attached to the body of polycrystalline super hard material along an interface and a plurality of apertures or channels. One or more of said apertures or channels extend(s) from the exposed working surface of the body into the substrate.

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 method of making polycrystalline diamond material includes providing a fraction of diamond particles or grains and a sintering additive, the sintering additive comprising a carbon source of nano-sized particles or grains, forming the diamond particles and sintering additive into an aggregated mass, consolidating the aggregated mass and a binder material to form a green body, and subjecting the green body to conditions of pressure and temperature at which diamond is more thermodynamically stable than graphite and for a time sufficient to consume the sintering additive, sintering it and forming polycrystalline diamond material that is thermodynamically and crystallographically stable and is substantially devoid of any nano-structures.

Methods of preventing or reducing cutter loss in a steel body PDC drilling tool may include applying a hardfacing layer on a surface of a PDC cutter pocket to form a covered PDC cutter pocket, the hardfacing layer comprising a metal binder and coated tungsten carbide particles; and bonding a PDC cutter into the covered PDC cutter pocket with a brazing material. Steel body PDC drilling tools may include a steel body, a PDC cutter, a PDC cutter pocket, and a hardfacing layer. Methods of preventing or reducing cutter loss in a steel body PDC drilling tool may include applying a hardfacing layer on a surface of a PDC cutter pocket of the steel body PDC drilling tool; applying a coated buffering layer on the hardfacing layer to form a coated PDC cutter pocket; and bonding the PDC cutter into the coated PDC cutter pocket with a brazing material.