Screw-in tool and tool holder for such a screw-in tool

A tool assembly, comprising:

• a tool insert including:
• a tool head having a work surface formed upon an end of the tool head, and a first conical bearing face formed upon the tool head adjacent the work surface;
• and
• a tool shank extending away from the tool head and having
• a peripheral surface defining an outer periphery of the shank,
• an outer thread integrally formed upon the peripheral surface threadably engageable with a tool holder, the tool shank and the outer thread thereby formed as one piece, and
• a second conical bearing face formed in the tool shank and positioned along the peripheral surface,
• the first and second conical bearing faces integrally formed upon the tool shank, each shaped to directly contact and mate with a respective corresponding conical bearing face of the holder without an intervening part,
• the first and second conical bearing faces define first and second cones, respectively, which are coaxial and have apexes which point in a same direction and which define cone angles, defined as an angle formed by bisecting a cone, of between 140° and 179° for the first conical bearing face and between 1° to 90° for the second conical bearing face;
• and
• a tool holder including:
• an inner bore;
• an inner thread formed within the inner bore, the inner thread mateable with the outer thread of the tool shank;
• and
• a holder supporting region forming the respective conical bearing faces of the holder, which include two conical bearing faces each having a surface which defines a cone having an apex which points towards a threading in a direction of the tool shank.

A tool holder for holding a tool insert, the tool holder comprising:

• a body having a bore defining an inner end and an entry end and defining a longitudinal axis extending between the inner end and the entry end;
• a first conical tool bearing face formed upon the body and positioned at the entry end and defining a cone angle, defined as an angle formed by bisecting a cone, of between 140 and 179 degrees;
• a second conical tool bearing face formed within the bore and positioned closer to the inner end than the first conical tool bearing face and defining an angle of 1 to 90 degrees with respect to the longitudinal axis;
• the first and second conical tool bearing faces thereby shaped to directly contact and mate with corresponding surfaces of a tool head, to thereby center the tool head with respect to the tool holder, and to bear a load transmitted through the tool holder to the tool head;
• an inner thread formed within the bore adjacent to the second conical tool bearing face and engageable with threads of the tool insert;
• a sealing surface located near the inner end;
• at least one radial borehole extending between an exterior side surface of the body and the inner end of the bore;
• and
• at least one channel for conducting a fluid to the inner end of the bore.