A drill bit for forming a wellbore through a geologic formation includes a connector configured for connection to a drill string and a bit body coupled to the connector. A fixed cutting element is mounted on the bit body for rotation with the bit body and a slot extends through the bit body. A rolling cutting blade is supported in the slot such that an exposed segment of the cutting blade protrudes from slot and concealed segments of the rolling cutting blade adjacent the exposed segment are disposed within the slot. The rolling cutting blade rotates to thereby conceal the exposed segment and expose the concealed segments. A plurality of rotating cutting elements are supported on a periphery of the rolling cutting blade.

A drill bit for forming a wellbore through a geologic formation includes a connector configured for connection to a drill string and a bit body coupled to the connector. A fixed cutting element is mounted on the bit body for rotation with the bit body and a slot extends through the bit body. A rolling cutting blade is supported in the slot such that an exposed segment of the cutting blade protrudes from slot and concealed segments of the rolling cutting blade adjacent the exposed segment are disposed within the slot. The rolling cutting blade rotates to thereby conceal the exposed segment and expose the concealed segments. A plurality of rotating cutting elements are supported on a periphery of the rolling cutting blade.

A drill bit for forming a wellbore through a geologic formation includes a connector configured for connection to a drill string and a bit body coupled to the connector. A fixed cutting element is mounted on the bit body for rotation with the bit body and a slot extends through the bit body. A rolling cutting blade is supported in the slot such that an exposed segment of the cutting blade protrudes from slot and concealed segments of the rolling cutting blade adjacent the exposed segment are disposed within the slot. The rolling cutting blade rotates to thereby conceal the exposed segment and expose the concealed segments. A plurality of rotating cutting elements are supported on a periphery of the rolling cutting blade.

A drill bit for forming a wellbore through a geologic formation includes a connector configured for connection to a drill string and a bit body coupled to the connector. A fixed cutting element is mounted on the bit body for rotation with the bit body and a slot extends through the bit body. A rolling cutting blade is supported in the slot such that an exposed segment of the cutting blade protrudes from slot and concealed segments of the rolling cutting blade adjacent the exposed segment are disposed within the slot. The rolling cutting blade rotates to thereby conceal the exposed segment and expose the concealed segments. A plurality of rotating cutting elements are supported on a periphery of the rolling cutting blade.

A cutter head arrangement comprising a cutter head portion including a cutter head side wall to define a chamber (or cavity) surrounded by the cutter head side wall. A substantially circular rim portion extends from (a distal end of) the cutter head side wall, the rim portion defining a working, contact face of the cutter head portion. A recessed wall portion extends away from the rim portion inwardly into the chanber so as to be surrounded by the cutter head side wall, with the rim portion and/or the recessed wall portion being fitter with a plurality of cutter elemenets, to enable the cutter head portion to blind bore a pilot hole in use. The recessed wall portion that extends away from the rim portion inwardly into the chamber is a substantially conical body so as to define a conical recess.

A cutter head arrangement comprising a cutter head portion including a cutter head side wall to define a chamber (or cavity) surrounded by the cutter head side wall. A substantially circular rim portion extends from (a distal end of) the cutter head side wall, the rim portion defining a working, contact face of the cutter head portion. A recessed wall portion extends away from the rim portion inwardly into the chanber so as to be surrounded by the cutter head side wall, with the rim portion and/or the recessed wall portion being fitter with a plurality of cutter elemenets, to enable the cutter head portion to blind bore a pilot hole in use. The recessed wall portion that extends away from the rim portion inwardly into the chamber is a substantially conical body so as to define a conical recess.

Embodiments of the invention relate to polycrystalline diamond compacts (PDC) exhibiting enhanced diamond-to-diamond bonding. In an embodiment, PDC includes a sintered substantially single-phase polycrystalline diamond (PCD) body consisting essentially of bonded-together diamond grains exhibiting a morphology different than that of a PCD body formed by sintering diamond crystals. A substrate is bonded to the sintered substantially single-phase PCD body. Other embodiments are directed to methods of forming such PDCs, and various applications for such PDCs in rotary drill bits, bearing apparatuses, and wire-drawing dies.

Embodiments of the invention relate to polycrystalline diamond compacts (PDC) exhibiting enhanced diamond-to-diamond bonding. In an embodiment, PDC includes a sintered substantially single-phase polycrystalline diamond (PCD) body consisting essentially of bonded-together diamond grains exhibiting a morphology different than that of a PCD body formed by sintering diamond crystals. A substrate is bonded to the sintered substantially single-phase PCD body. Other embodiments are directed to methods of forming such PDCs, and various applications for such PDCs in rotary drill bits, bearing apparatuses, and wire-drawing dies.

The invention relates to hole forming tools suitable for use in subterranean drilling operations, operable with two non-parallel rotational motions for forming a hole of substantially circular cross section in a material, the tool comprising a rotatable drill body (17) having a proximal end (19) for attachment to a drive mechanism and a distal end (21) on which is disposed at least one rotatable cutting member (23), wherein the or each rotatable cutting member (23) independently extends away from said distal end (21); the or each rotatable cutting member (23) independently being substantially concentric with and supported by a cantilever shaft (35); wherein on the or each rotatable cutting member (23) is disposed at least one cutting structure (24), the or each cutting structure (24) independently having a cutting face with a continuous cutting edge which is substantially concentric with the axis of rotation of said rotatable cutting member (23).

The invention relates to hole forming tools suitable for use in subterranean drilling operations, operable with two non-parallel rotational motions for forming a hole of substantially circular cross section in a material, the tool comprising a rotatable drill body (17) having a proximal end (19) for attachment to a drive mechanism and a distal end (21) on which is disposed at least one rotatable cutting member (23), wherein the or each rotatable cutting member (23) independently extends away from said distal end (21); the or each rotatable cutting member (23) independently being substantially concentric with and supported by a cantilever shaft (35); wherein on the or each rotatable cutting member (23) is disposed at least one cutting structure (24), the or each cutting structure (24) independently having a cutting face with a continuous cutting edge which is substantially concentric with the axis of rotation of said rotatable cutting member (23).