Structures for a tool surface of a downhole tool are constructed from a metal clay molded in a wet state. The wet state clay is a workable combination that can have a braze alloy grain, a tungsten carbide grain, and a binder. Additional cutting inserts can be embedded in the molded clay. Heat treatment applied to the molded metal clay causing the binder to be combusted and consumed. The braze alloy melts and then cools into a fused state with the tungsten carbide grain therein. The structure can affix to the tool surface of the tool by first being fused and then attached by brazing to the tool. Alternatively, the structure can be positioned in a fusible state adjacent the tool surface. When the heat treatment is applied, the structure fuses together and forms a metallurgical bond with the tool surface of the tool.

A blank for a shaft milling tool having a generally cylindrical body of solid carbide, a rear portion and a front portion, the periphery of which front portion being designed for chip flutes to be formed therein, is made according to a method including the step of providing at least two separate green bodies having at least one axially extending inner channel, which are fitted together along a common interface and sintered together to form a unitary body. For a more economic production of blanks with radially extending channels at least one generally radially extending channel is formed in at least one of the connecting surfaces before sintering the bodies together. The channel is formed with its radially inner end configured for fluid communication with the axial channel and with a radial extension to a position corresponding to at least 40% of the outer radius of the blank.

A blank for a shaft milling tool having a generally cylindrical body of solid carbide, a rear portion and a front portion, the periphery of which front portion being designed for chip flutes to be formed therein, is made according to a method including the step of providing at least two separate green bodies having at least one axially extending inner channel, which are fitted together along a common interface and sintered together to form a unitary body. For a more economic production of blanks with radially extending channels at least one generally radially extending channel is formed in at least one of the connecting surfaces before sintering the bodies together. The channel is formed with its radially inner end configured for fluid communication with the axial channel and with a radial extension to a position corresponding to at least 40% of the outer radius of the blank.

A milling tool, preferably a fir tree cutter, having an operating area which is rotatable about an operating axis of rotation for milling a workpiece and comprises a milling edge which extends transversely to the circumferential direction (U) of an operating axis of rotation, wherein the at least one milling edge includes at least one milling edge portion in which a milling edge profile (P), which is defined by the radial distance (F) between the milling edge and the operating axis of rotation along the milling edge, comprises a non-linear progression, wherein the milling edge in the milling edge portion comprises a chip space, which extends radially inward toward the operating axis of rotation in relation to the milling edge and comprises a chip space base which follows the milling edge profile (P) at least in portions in the milling edge portion with the non-linear milling edge profile (P).

A milling tool, preferably a fir tree cutter, having an operating area which is rotatable about an operating axis of rotation for milling a workpiece and comprises a milling edge which extends transversely to the circumferential direction (U) of an operating axis of rotation, wherein the at least one milling edge includes at least one milling edge portion in which a milling edge profile (P), which is defined by the radial distance (F) between the milling edge and the operating axis of rotation along the milling edge, comprises a non-linear progression, wherein the milling edge in the milling edge portion comprises a chip space, which extends radially inward toward the operating axis of rotation in relation to the milling edge and comprises a chip space base which follows the milling edge profile (P) at least in portions in the milling edge portion with the non-linear milling edge profile (P).

A rotary cutting tool (10) has an axis of rotation (R) and a tool body (12) extending along the axis of rotation (R) and having at least one coolant channel (30). At least a portion (32) of the at least one coolant channel (30) is formed by a groove (40) in a circumferential face (42) of the tool body (12). Furthermore, the at least one coolant channel (30) in the portion (32) of the groove (40) is closed in the radial direction by an add-on part of the rotary cutting tool (10) attached to the tool body (12). Furthermore, a method for manufacturing such a rotary cutting tool (10) is provided.

A rotary cutting tool (10) has an axis of rotation (R) and a tool body (12) extending along the axis of rotation (R) and having at least one coolant channel (30). At least a portion (32) of the at least one coolant channel (30) is formed by a groove (40) in a circumferential face (42) of the tool body (12). Furthermore, the at least one coolant channel (30) in the portion (32) of the groove (40) is closed in the radial direction by an add-on part of the rotary cutting tool (10) attached to the tool body (12). Furthermore, a method for manufacturing such a rotary cutting tool (10) is provided.

A cutting tool according to an aspect of the present disclosure includes a cutting edge portion which contains at least one of cubic boron nitride and polycrystalline diamond. The cutting edge portion includes a rake face, a flank face, and a cutting edge. The flank face is contiguous to the rake face. The cutting edge is provided as a ridge line between the rake face and the flank face. The radius of curvature of the cutting edge is 2 m or more and 8 m or less.

A cutting tool according to an aspect of the present disclosure includes a cutting edge portion which contains at least one of cubic boron nitride and polycrystalline diamond. The cutting edge portion includes a rake face, a flank face, and a cutting edge. The flank face is contiguous to the rake face. The cutting edge is provided as a ridge line between the rake face and the flank face. The radius of curvature of the cutting edge is 2 m or more and 8 m or less.

A cutting tool body includes a first member and a second member, both having a substantially cylindrical shape, and arranged such that a tool body central axis coincides with a central axis of each of the first and the second members. The first member has a tool characteristic of a first magnitude and the second member has the tool characteristic of a second magnitude, different from the first magnitude. The cutting tool body includes a transition member arranged between the first and second members and connected at a first end to the first member and at a second end to the second member. The tool characteristic in the transition member is of the first magnitude at the first end and of the second magnitude at the second end. The transition member has a transition region between the first and the second ends in which the tool characteristic transforms from the first magnitude to the second magnitude.