A cutter block includes a formation facing surface having a staged cutting profile and one or more stabilizer pads may be located between reaming portions. A shorter stabilizer pad or no stabilizer pad may be at the gauge of the cutter block. A spline on the cutter block and used by a downhole cutting apparatus to move the cutter block may intersect the formation facing surface. The spline may form an extension that increases a width of the formation facing surface. The extension may be located at a stabilizer pad to expand the stabilizer pad, such that the extension rotationally leads or trails cutting structure of the cutter block. When the cutter block is expanded, a stabilizer pad may be at a pilot diameter of a wellbore, while some cutting elements may be radially outside, and others radially within, the pilot diameter of the wellbore.

An example drill bit is formed by a bit head portion and a shank portion. The bit head portion includes a bit face, and the shank includes a bit portion and a bit connection. The bit connection is configured to be coupled to a drill string. The bit head and shank are configured to be secured together. When secured together, one or more blades that start near a central axis of the bit face continue to a gage portion of the bit and along at least a portion of the length of the bit portion of the shank. One or more anchoring elements are coupled to the bit head and the shank to restrict relative rotational or axial movement between the bit head and the shank.

A downhole stabilizer (5), such as a drill motor stabilizer, comprises at least one reaming means and/or reinforcing means (10). The present invention also relates to an assembly (30), such as a downhole drilling assembly (31), comprising at least one such stabilizer (5) and/or a drill bit (40,41) comprising a gauge bit (42) at or near a drilling end (45) thereof, and a connection means (46) for connecting the drill bit (40,41) to a drill motor assembly (60), wherein the drill bit gauge (42) comprises a substantially cylindrical portion having a length less than or equal to approximately 1.0 times the nominal bit diameter. The present invention also relates to a novel locking mechanism (80), such as a lock and key mechanism, to allow locking of a shaft (70), e.g. a motor drive shaft (71), through or together with a stabilizer (5).

A polycrystalline diamond drill bit for percussion drilling, in small hole high silica ground is disclosed which has a cutting face having an inner flat face and an outer beveled peripheral surface, a number of first polycrystalline diamond tipped inserts having a first diameter inserted into the inner flat face and the outer beveled peripheral surface, and a number of second polycrystalline diamond tipped inserts having a second diameter inserted into the inner flat face, with the second diameter being different than the first diameter. 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. The percussion drilling, with larger bits, may be used for rotary oil drilling, and operating at a machine thrust and torque of less than 20 Bar.

A turbine-drill bit assembly is disclosed. The assembly comprises a box connection turbine connected to a pin connection drill bit. The turbine has a turbine body around a turbine shaft, the turbine body having a turbine stabilizer. The drill bit has a bit gauge or a bit sleeve around a bit shank, an end of the turbine stabilizer nearest the drill bit being spaced a first maximum distance from an end of the bit gauge or bit sleeve. In addition, a shouldering interface is formed at respective abutment shouldering surfaces of the turbine shaft and bit shank when the drill bit is attached to the turbine shaft, the interface being spaced a second maximum distance from an end of the bit gauge or bit sleeve.

Earth-boring tools may include a body and a passively adjustable, aggressiveness-modifying member secured to the body. The passively adjustable, aggressiveness-modifying member may be movable between a first position in which the earth-boring tool exhibits a first aggressiveness and a second position in which the earth-boring tool exhibits a second, different aggressiveness responsive to forces acting on the passively adjustable, aggressiveness-modifying member.

A rotary downhole tool, for example in the form of a drill bit, is described that includes a tool body, the body defining a gauge region, and at least one gauge roller rotatably mounted to the body.

A method includes positioning at least one guide projection on a substrate of a metal part such that the at least one guide projection extends outwardly from an outer surface of the substrate to an exposed length. Hardfacing is then applied to the substrate of the metal part at or near a location of the at least one guide projection. The exposed length of the at least one guide projection is then referenced in determining when to cease application of the hardfacing.

A steerable rock bit attached by a drill string to a horizontal directional drill. The bit comprises a plurality of flanges radially extending from a central hub and a slanted face formed in the body of the bit. Cutting elements such as polycrystalline diamond compacts are disposed on the flanges on one side of the flanges such that they will provide cutting force when the bit is rotated in the direction of the cutting elements. The bit is advanced generally straight when the bit is rotated and is advanced at an angle away from the slanted face when the bit is not rotated.

Earth-boring tools may include a body and a passively adjustable, aggressiveness-modifying member secured to the body. The passively adjustable, aggressiveness-modifying member may be movable between a first position in which the earth-boring tool exhibits a first aggressiveness and a second position in which the earth-boring tool exhibits a second, different aggressiveness responsive to forces acting on the passively adjustable, aggressiveness-modifying member.