A rotary dill bit with a drill bit head and a connecting portion, wherein the rotary bit is positioned and oriented for shearing a surface of a subterranean formation. The drill bit head is comprised of one or more cutting discs, wherein each cutting disc is rotatably mounted to at least one shaft between a pair of support structures with each cutting disc having a cutting disc edge extending outwardly beyond the support structures. The cutting discs have cutting inserts in an overlapping pattern, wherein each cutting insert comprises a projection extending from the cutting disc edge and angled from the cutting disc edge at a side rake and a front rake angle.

A rotary dill bit with a drill bit head and a connecting portion, wherein the rotary bit is positioned and oriented for shearing a surface of a subterranean formation. The drill bit head is comprised of one or more cutting discs, wherein each cutting disc is rotatably mounted to at least one shaft between a pair of support structures with each cutting disc having a cutting disc edge extending outwardly beyond the support structures. The cutting discs have cutting inserts in an overlapping pattern, wherein each cutting insert comprises a projection extending from the cutting disc edge and angled from the cutting disc edge at a side rake and a front rake angle.

A hybrid bit includes a fixed cutting structure and a rolling cutting structure. The fixed cutting structure includes a plurality of fixed cutting elements. The rolling cutting structure is coupled to the fixed cutting structure and includes a journal bore extending through the rolling cutting structure from a leading face to a trailing face, and a radially outer surface. The rolling cutting structure also includes a plurality of cutting elements extending from the radially outer surface of the rolling cutting structure.

A hybrid bit includes a fixed cutting structure and a rolling cutting structure. The fixed cutting structure includes a plurality of fixed cutting elements. The rolling cutting structure is coupled to the fixed cutting structure and includes a journal bore extending through the rolling cutting structure from a leading face to a trailing face, and a radially outer surface. The rolling cutting structure also includes a plurality of cutting elements extending from the radially outer surface of the rolling cutting structure.

A composite sintered body cutting tool, in which tungsten is reduced, is made of a TiCN-based cermet and WC-based cemented carbide. The cutting tool has an angle of less than 90 degrees formed by a rake face and a flank face. The rake face including a cutting edge contains WC-based cemented carbide including 4% to 17% by mass of iron group metal components with a remainder being WC. The thickness of the carbide is 0.05 to 0.3 times the thickness of the composite sintered body. The TiCN-based cermet which is a base body of the cutting tool includes 4% to 25% of the iron group metal components, less than 15% of W, 2% to 15% of Mo, 2% to 10% of Nb, and 0.2% to 2% of Cr. The cermet may contain iron group metal Co and Ni, where, Co/Co+Ni is 0.5 to 0.8.

A composite sintered body cutting tool, in which tungsten is reduced, is made of a TiCN-based cermet and WC-based cemented carbide. The cutting tool has an angle of less than 90 degrees formed by a rake face and a flank face. The rake face including a cutting edge contains WC-based cemented carbide including 4% to 17% by mass of iron group metal components with a remainder being WC. The thickness of the carbide is 0.05 to 0.3 times the thickness of the composite sintered body. The TiCN-based cermet which is a base body of the cutting tool includes 4% to 25% of the iron group metal components, less than 15% of W, 2% to 15% of Mo, 2% to 10% of Nb, and 0.2% to 2% of Cr. The cermet may contain iron group metal Co and Ni, where, Co/Co+Ni is 0.5 to 0.8.

A control method for the use of a core drilling system, including a core drill and a feed device for driving the core drill along a machine holding unit, including the method steps: detecting at least one first drilling parameter value during the core drilling operation; establishing the at least first drilling parameter value as a reference value; detecting at least one second drilling parameter value during the core drilling operation; comparing the at least second core drilling parameter with the reference value; and selecting a predetermined parameter setting for the core drilling system if the second drilling parameter exceeds or falls below the reference value by a predetermined corresponding threshold value. Also a feed device for driving a core drill along a machine holding unit for use of the method, a core drill for use of the method as well as a core drilling system including a core drill and a feed device for driving the core drill along a machine holding unit for use of the method.

A control method for the use of a core drilling system, including a core drill and a feed device for driving the core drill along a machine holding unit, including the method steps: detecting at least one first drilling parameter value during the core drilling operation; establishing the at least first drilling parameter value as a reference value; detecting at least one second drilling parameter value during the core drilling operation; comparing the at least second core drilling parameter with the reference value; and selecting a predetermined parameter setting for the core drilling system if the second drilling parameter exceeds or falls below the reference value by a predetermined corresponding threshold value. Also a feed device for driving a core drill along a machine holding unit for use of the method, a core drill for use of the method as well as a core drilling system including a core drill and a feed device for driving the core drill along a machine holding unit for use of the method.

A method comprising identifying a cutter on a drill bit based on a drill bit image, assigning a grading value of the cutter based on a classification model of a machine learning system, wherein the classification model is generated based on a set of training cutter images associated with drill bit characteristics indicators, determining a surface parameter based on a surface of the cutter, generating a comparison value based on the surface parameter, and mapping a set of cutter information to the cutter on the drill bit, wherein the set of cutter information comprises the grading value and the comparison value.

A method comprising identifying a cutter on a drill bit based on a drill bit image, assigning a grading value of the cutter based on a classification model of a machine learning system, wherein the classification model is generated based on a set of training cutter images associated with drill bit characteristics indicators, determining a surface parameter based on a surface of the cutter, generating a comparison value based on the surface parameter, and mapping a set of cutter information to the cutter on the drill bit, wherein the set of cutter information comprises the grading value and the comparison value.