A drill assembly (10) for use in trenchless subterranean boring, comprising: a drill shoe (20) having a body with a posterior portion (30) and an anterior portion (22), the latter defining a recess while the former comprises drill bits (32) disposed on a front end (34), opposing lateral sides, and flanks to assist the shoe (20) in acting as both pilot bore drilling tool and as reaming tool; a drill head (50) demount ably mounted to tire drill shoe (20) via tire recess and in communication with directional guidance means; a string of connectable drill rods (80), having a bailing end (82) and a leading end (84) when connected, and through which a drilling solution can be pumped towards tire drill shoe (20); a coupling (86) for linking tire leading end (84) to said drill head (50); and a connector (88) for connecting the trailing end (82) to a vehicle. The invention extends to a drill shoe (20) and a method of use and manufacture thereof.

An earth boring tool includes a tool body and a cutting element secured to the tool body. The tool body has at least one surface defining a cutting element recess where the cutting element is secured within the cutting element recess by a braze material. The cutting element includes a generally cylindrical substrate having at least one outer surface defining a braze recess. The braze material is disposed at an interface between the cutting element and the cutting element recess, including within the braze recess of the generally cylindrical substrate. The tool body does not include a surface defining a feature on the tool body complementary to the braze recess in the generally cylindrical substrate.

An earth boring tool includes a tool body and a cutting element secured to the tool body. The tool body has at least one surface defining a cutting element recess where the cutting element is secured within the cutting element recess by a braze material. The cutting element includes a generally cylindrical substrate having at least one outer surface defining a braze recess. The braze material is disposed at an interface between the cutting element and the cutting element recess, including within the braze recess of the generally cylindrical substrate. The tool body does not include a surface defining a feature on the tool body complementary to the braze recess in the generally cylindrical substrate.

A cutting element includes a substrate and a volume of polycrystalline diamond (PDC) on the substrate. The PDC volume has a front cutting face, a lateral side surface, and a cutting edge between the front cutting face and the lateral side surface. The cutting edge has a cutting apex and extends between a first side flat surface and a second side flat surface. The side flat surfaces are disposed on opposing sides of the cutting apex. The cutting edge further includes a first chamfer surface and a second chamfer surface, which are located adjacent to one another and oriented at a first angle relative to one another at the cutting apex. The cutting edge includes one of: an arcuate edge having a radius of curvature; and a linear edge having discrete linear edges adjacent one another and separated by a second angle.

A drill bit and method incorporate backup assemblies that limit depth of engagement of cutters with the formation. The backup assemblies dynamically adjust exposure relative to a cutting profile in response to downhole loading conditions. In an example, cutters are secured to the cone, nose, shoulder, and/or gage regions of the bit body. One or more backup assemblies are provided on the cone, nose, or shoulder region, and optionally, on the gauge region. A backup element on an outwardly facing end of the piston limits a depth of cut of one or more of the cutters. The backup element may be rigidly secured or rotatably secured to the piston. The piston may be biased outwardly to a neutral position aligned with or overexposed relative to the cutting profile.

A drill bit and method incorporate backup assemblies that limit depth of engagement of cutters with the formation. The backup assemblies dynamically adjust exposure relative to a cutting profile in response to downhole loading conditions. In an example, cutters are secured to the cone, nose, shoulder, and/or gage regions of the bit body. One or more backup assemblies are provided on the cone, nose, or shoulder region, and optionally, on the gauge region. A backup element on an outwardly facing end of the piston limits a depth of cut of one or more of the cutters. The backup element may be rigidly secured or rotatably secured to the piston. The piston may be biased outwardly to a neutral position aligned with or overexposed relative to the cutting profile.

A drill bit using track-set depth of cut control elements to provide improved stability is disclosed. A drill bit for drilling a wellbore includes a bit body with a rotational axis extending therethrough. The drill bit further includes a plurality of blades disposed on exterior portions of the bit body. The drill bit includes a first group of track set depth of cut controllers (DOCCs) disposed on exterior portions of a first set of the plurality of blades. The first group of track set DOCCs configured to be placed within a first radial swath of a bit face of the drill bit and configured to provide a first critical depth of cut (CDOC).

Roller cutters comprise a diamond-bonded body joined to an infiltration substrate. An extension is joined to the substrate and includes first section having a diameter sized the same as the substrate, and an integral second section having a diameter smaller than the substrate. The extension is joined to the substrate during an HPHT process. The first section has a thickness greater than that of the infiltration substrate. The second section has an axial length greater than the combined thickness of the substrate and the first section. The extension has a strength and/or toughness greater than the substrate as a result of its material composition, e.g., the amount of binder phase material and/or the size of hard phase material. The roller cutter is rotatably disposed within a pocket internal cavity, wherein the pocket is attached to a

A cutting head includes a main body that is attachable to an ice drill shaft at a top side. The main body includes a bottom side that has a bottom peripheral surface. The cutting head includes at least one cutting edge that is disposed on the main body. The cutting edge is configured to perform a cutting operation at the bottom side of the main body. The cutting head includes a cutting rate control pad that is disposed on the bottom side of the main body. The cutting rate control pad extends away from the bottom peripheral surface.

A cutting head includes a main body that is attachable to an ice drill shaft at a top side. The main body includes a bottom side that has a bottom peripheral surface. The cutting head includes at least one cutting edge that is disposed on the main body. The cutting edge is configured to perform a cutting operation at the bottom side of the main body. The cutting head includes a cutting rate control pad that is disposed on the bottom side of the main body. The cutting rate control pad extends away from the bottom peripheral surface.