Rotary drill bits may include on or more cutting element assemblies which include a cutter and a mounting system. In one embodiment, the mounting system includes a housing, a first bearing component disposed within the housing, and a second bearing component associated with the cutting element. In certain embodiments, the bearing components may comprise a table of superhard material bonded with a substrate. In one or more embodiments, the bearing components may include bearing surfaces that are arcuate. For example, the bearing surfaces may be substantially spherical (a portion of a sphere). The bearing components may be arranged to act as a radial bearing as well as a thrust bearing for the cutting element, enabling the cutting element to rotate about a longitudinal axis of the cutter, relative to the housing, while also enabling the longitudinal axis of the cutter to be displaced (change angles) relative to the housing.

A steel constituting a chisel according to the present invention includes: 0.40-0.45% by mass of carbon, 0.50-0.80% by mass of silicon, 1.00-1.30% by mass of manganese, 0.001-0.005% by mass of sulfur, 2.90-3.80% by mass of chromium, and 0.20-0.40% by mass of molybdenum, with a balance consisting of iron and an unavoidable impurity, the steel has an ideal critical diameter DI defined by Equation (1) of 600 or more:
DI=7.Math.(% C).sup.1/2.Math.(1+0.64.Math.% Si).Math.(1+4.1.Math.% Mn).Math.(1+2.83.Math.% P).Math.(1−0.62.Math.% S).Math.(1+2.33.Math.% Cr).Math.(1+3.14.Math.% Mo)  (1).

A steel constituting a chisel according to the present invention includes: 0.40-0.45% by mass of carbon, 0.50-0.80% by mass of silicon, 1.00-1.30% by mass of manganese, 0.001-0.005% by mass of sulfur, 2.90-3.80% by mass of chromium, and 0.20-0.40% by mass of molybdenum, with a balance consisting of iron and an unavoidable impurity, the steel has an ideal critical diameter DI defined by Equation (1) of 600 or more:
DI=7.Math.(% C).sup.1/2.Math.(1+0.64.Math.% Si).Math.(1+4.1.Math.% Mn).Math.(1+2.83.Math.% P).Math.(1−0.62.Math.% S).Math.(1+2.33.Math.% Cr).Math.(1+3.14.Math.% Mo)  (1).

A drill bit assembly for drilling a hole through earth, the drill bit comprising: a bit body extending between a first end and a second end along a longitudinal axis of the bit body with a connecting arrangement positioned at the first end of the bit body for coupling the bit body to a rotating shaft for providing rotational torque to the bit body; a cutting head including a leading tip portion for cutting into earth and a trailing receiving portion for receiving the second end of the bit body in an internal cavity defined by the receiving portion to allow the cutting head to be removably coupled to the second end of the bit body; a retaining arrangement to retain the second end of the bit body in the receiving portion of the cutting tip.

A drill bit assembly for drilling a hole through earth, the drill bit comprising: a bit body extending between a first end and a second end along a longitudinal axis of the bit body with a connecting arrangement positioned at the first end of the bit body for coupling the bit body to a rotating shaft for providing rotational torque to the bit body; a cutting head including a leading tip portion for cutting into earth and a trailing receiving portion for receiving the second end of the bit body in an internal cavity defined by the receiving portion to allow the cutting head to be removably coupled to the second end of the bit body; a retaining arrangement to retain the second end of the bit body in the receiving portion of the cutting tip.

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.

The present disclosure provides downhole tools, methods for three dimensional printing hardfacing on such downhole tools, and systems for implementing such methods.

The present disclosure provides downhole tools, methods for three dimensional printing hardfacing on such downhole tools, and systems for implementing such methods.

The present disclosure provides a cutting head adapted to removably couple to a bit body of a drill bit assembly. The cutting head includes a leading cutting tip for cutting into earth and a trailing receiving portion for receiving a second end of the bit body in an internal cavity defined by the trailing receiving portion to allow the cutting head to be removably coupled to the second end of the bit body.