Methods and systems for maintaining a drill bit includes positioning a cutter within a recess of a drill bit body so that an initial edge is positioned at a first location that is a radially outward location relative to a blade of the drill bit. A threaded member extended through a central bore of the cutter can be rotated to releasably secure the cutter to the drill bit. The subterranean well is drilled with the drill bit. The threaded member can be rotated in a second direction so that the cutter can be rotated relative to the recess and the initial edge of the cutter is positioned at a second location that is rotationally offset from the first location. The threaded member can be rotated to releasably re-securing the cutter to the drill bit and the subterranean well can continue to be drilled with the drill bit.

Methods and systems for maintaining a drill bit includes positioning a cutter within a recess of a drill bit body so that an initial edge is positioned at a first location that is a radially outward location relative to a blade of the drill bit. A threaded member extended through a central bore of the cutter can be rotated to releasably secure the cutter to the drill bit. The subterranean well is drilled with the drill bit. The threaded member can be rotated in a second direction so that the cutter can be rotated relative to the recess and the initial edge of the cutter is positioned at a second location that is rotationally offset from the first location. The threaded member can be rotated to releasably re-securing the cutter to the drill bit and the subterranean well can continue to be drilled with the drill bit.

An insert for a drill bit includes a base portion having a central axis and a formation engaging portion. The formation engaging portion includes an elongate peaked ridge, a first flanking surface extending from the peaked ridge, and a second flanking surface extending from the peaked ridge. The first flanking surface is defined by a first curve rotated about a first axis and the second flanking surface is defined by a second curve rotated about a second axis. The first axis and the second axis are disposed in a reference plane that bisects the base portion and contains the central axis of the base portion. The first axis is disposed at a first radius measured in the reference plane and the second axis is disposed at a second radius measured in the reference plane. The first radius is different from the second radius.

An insert for a drill bit includes a base portion having a central axis and a formation engaging portion. The formation engaging portion includes an elongate peaked ridge, a first flanking surface extending from the peaked ridge, and a second flanking surface extending from the peaked ridge. The first flanking surface is defined by a first curve rotated about a first axis and the second flanking surface is defined by a second curve rotated about a second axis. The first axis and the second axis are disposed in a reference plane that bisects the base portion and contains the central axis of the base portion. The first axis is disposed at a first radius measured in the reference plane and the second axis is disposed at a second radius measured in the reference plane. The first radius is different from the second radius.

An Earth drill bit includes a bit body assembly and a plurality of separately movable cutting elements carried by the bit body assembly. The bit body assembly is arranged around a central bit body axis and includes a hydraulic circuit. The plurality of separately movable cutting elements is movable in a direction parallel to the central bit body axis and supported by fluid in the hydraulic circuit.

An Earth drill bit includes a bit body assembly and a plurality of separately movable cutting elements carried by the bit body assembly. The bit body assembly is arranged around a central bit body axis and includes a hydraulic circuit. The plurality of separately movable cutting elements is movable in a direction parallel to the central bit body axis and supported by fluid in the hydraulic circuit.

A bladeless polycrystalline diamond compact (PDC) drill bit includes a head having a plurality of knots protruding from a drilling face of the head. Each of the plurality of knots includes a single cutter. Each of the cutters is arranged about a central axis of the head such that each cutter has a unique radial position and angular position relative to the central axis. The head defines at least one fluid port extending through the drilling surface.

A drill bit for drilling a borehole in earth formations may include a bit body having a bit axis and a bit face; a plurality of blades extending radially along the bit face; and a plurality of cutting elements disposed on the plurality of blades, the plurality of cutting elements comprising: at least one cutter comprising a substrate and a diamond table having a substantially planar cutting face; and at least two non-planar cutting elements comprising a substrate and a diamond layer having a non-planar cutting end, wherein in a rotated view of the plurality of cutting elements into a single plane, the at least one cutter is located a radial position from the bit axis that is intermediate the radial positions of the at least two non-planar cutting elements.

A drilling tool has: a casing pipe in a circular tubular shape; a cylindrical or annular ring bit rotatably fitted to a tip portion of the casing pipe; and a pilot bit inserted into an inner circumference of the ring bit for a striking force to be exerted to toward a tip end side, wherein the ring bit is engaged with and fitted to the casing pipe, projections are formed on an outer circumferential portion of the pilot bit, a recessed trench, and a housing trench, are formed in the inner circumferential part of the ring bit, a torque transmitting surface is formed in the projection, a torque receiving surface capable of abutting the torque transmitting surface is formed in the housing trench, striking force transmitting surfaces are formed in projections, and striking force receiving surfaces capable of abutting the striking force transmitting surfaces are formed in the ring bit.

A drilling tool has: a casing pipe in a circular tubular shape; a cylindrical or annular ring bit rotatably fitted to a tip portion of the casing pipe; and a pilot bit inserted into an inner circumference of the ring bit for a striking force to be exerted to toward a tip end side, wherein the ring bit is engaged with and fitted to the casing pipe, projections are formed on an outer circumferential portion of the pilot bit, a recessed trench, and a housing trench, are formed in the inner circumferential part of the ring bit, a torque transmitting surface is formed in the projection, a torque receiving surface capable of abutting the torque transmitting surface is formed in the housing trench, striking force transmitting surfaces are formed in projections, and striking force receiving surfaces capable of abutting the striking force transmitting surfaces are formed in the ring bit.