The invention is a multidirectional auger bit mounted on an auger head, and includes a base portion having a distal end that protrudes in an axial direction of the auger head, and leg portions that is continuous with the base portion. The base portion includes a flat portion that is continuous with the leg portion, first inclined portions that are inclined from the flat portion toward a distal end side in the axial direction of the auger head, left and right side surface portions that are continuous from the first inclined portion, and a second inclined portion that is inclined from the first inclined portion toward a leg portion side in the axial direction of the auger head.

Cutting elements for an earth-boring tool include a substrate base and a cutting tip. The cutting tip may include a first generally conical surface, a second, opposite generally conical surface, a first flank surface extending between the first and second generally conical surfaces, and a second, opposite flank surface. The cutting tip may include a central axis that is not co-linear with a longitudinal axis of the substrate base. The cutting tip may include a surface defining a longitudinal end thereof that is relatively more narrow in a central region thereof than in a radially outer region thereof. Earth-boring tools include a body and a plurality of such cutting elements attached thereto, at least one cutting element oriented to initially engage a formation with the first or second generally conical surface thereof. Methods of drilling a formation use such cutting elements and earth-boring tools.

Cutting elements for an earth-boring tool include a substrate base and a cutting tip. The cutting tip may include a first generally conical surface, a second, opposite generally conical surface, a first flank surface extending between the first and second generally conical surfaces, and a second, opposite flank surface. The cutting tip may include a central axis that is not co-linear with a longitudinal axis of the substrate base. The cutting tip may include a surface defining a longitudinal end thereof that is relatively more narrow in a central region thereof than in a radially outer region thereof. Earth-boring tools include a body and a plurality of such cutting elements attached thereto, at least one cutting element oriented to initially engage a formation with the first or second generally conical surface thereof. Methods of drilling a formation use such cutting elements and earth-boring tools.

A cutting element comprises a supporting substrate, and a cutting table attached to the supporting substrate and comprising a substantially planar apex, opposing flat surfaces extending upwardly and inwardly toward the substantially planar apex from locations proximate an interface between the cutting table and the supporting substrate, primary edge surfaces between the substantially planar apex and the opposing flat surfaces and exhibiting one or more of a radiused geometry and a chamfered geometry, opposing semi-conical surfaces intervening between the opposing flat surfaces and extending upwardly and inwardly toward the substantially planar apex from other locations proximate the interface between the cutting table and the supporting substrate, and secondary edge surfaces between the substantially planar apex and the opposing semi-conical surfaces and exhibiting one or more of another radiused geometry and another chamfered geometry. An earth-boring tool and a method of forming a cutting element are also described.

A subterranean support-bolt drilling assembly has a drill bit rotatable about a central axis and including at least one cutting edge. The drilling assembly also includes a spacer coupled to a rearward end of the drill bit. A reamer member is coupled to a rearward end of the spacer, the reamer member having at least one cutting element, the at least one cutting element having a cutting edge that extends radially beyond an outer peripheral portion of the drill bit relative to the central axis. A subterranean support-bolt drill bit includes a bit body and at least one cutting element coupled to the bit body. The support-bolt drill bit has a central pilot extending from the bit body in an axially forward direction. The cutting edge of the at least one cutting element extends radially beyond the central pilot relative to a central axis of the drill bit.

A drill head is provided with three main cutting edges each having a straight direction of extension with a predominant radial direction component. The directions of extension limit two adjacent main bore dust discharge sectors, each spanning a main sector angle. Three drill head cutting legs each forming a main cutting edge where the three main cutting edges have different lengths along their directions of extension. Concentric ring shaped removal areas overlap at least partially such that a triple removal area coverage is provided in an outer ring zone and a double removal area coverage is provided in an inner ring zone.

A drill head is provided with three main cutting edges each having a straight direction of extension with a predominant radial direction component. The directions of extension limit two adjacent main bore dust discharge sectors, each spanning a main sector angle. Three drill head cutting legs each forming a main cutting edge where the three main cutting edges have different lengths along their directions of extension. Concentric ring shaped removal areas overlap at least partially such that a triple removal area coverage is provided in an outer ring zone and a double removal area coverage is provided in an inner ring zone.

A roof-bolt drill bit includes a bit body that is rotatable about a central axis, a coupling pocket defined in the bit body, and at least one cutting element mounted to the bit body. The at least one cutting element includes a cutting face, a cutting edge adjacent the cutting face, a back surface opposite the cutting face, and a side surface extending between the cutting edge and the back surface. The roof-bolt drill bit additionally includes a coupling attachment coupled to the bit body, the coupling attachment being positioned adjacent to a portion of the side surface of the cutting element that abuts a side surface of the coupling pocket.

A drill bit includes a tool body having a main body in the form of a cylinder. A chip removing structure is provided on the main body. The tool body has a distal end provided with a clamping slot and a cutter inlaid in the clamping slot. The cutter has at least two blade portions arranged circumferentially on the distal end of the tool body and extending radially relative to the tool body. Each of the blade portions has a front side along the drill bit's rotating direction and a back side against the rotating direction. The clamping slot covers the back side of one blade portion by an area larger than that used to cover the front side of the same blade portion.

A polycrystalline diamond drill bit for percussion drilling, in small hole high silica ground. The bit is made having a bit body, and a series of inserts locating in the bit body, and the bits are made using a double chisel design, or a modified double chisel design. The inserts are either chiseled shaped inserts, or the inserts are a combination of chisel shaped inserts and conical inserts, and are set into the bit body at very specific angles, in order to attain slicing of the earth when percussion drilling is performed. The inserts have specific lengths to cut clearance for the bit body. The cutting angle and the radius of the tip of each insert in addition to the diameter of the inserts, provide for use of a machine thrust pressure and machine torque pressure at low ranges when the PCD bits are used in percussion drilling.