In a T-shaped tool (10) in which a head (30) having cutting edges (36, 38) and a cylindrical shank (20) are fastened together: the shank comprises a super-hard alloy, and an engaging portion which engages with a tool main body is formed in a distal end portion thereof; the tool main body comprises a steel material, and an engaged portion which engages with the engaging portion of the shank is formed therein; and the engaging portion and the engaged portion are fastened in such a way as to be retained and prevented from rotating.

A milling head for a ball track milling cutter includes an imaginary center axis, a first, working-side end and a second, clamping-side end opposite the first end when viewed along the central axis, and comprising at least one geometrically defined cutting edge, extending along a cutting edge profile of the cutting edge from a first cutting edge end facing the first end of the milling head in the direction of the second end of the milling head up to a second cutting edge end facing the second end of the milling head, wherein at least one cutting edge is formed as an intersecting line between the rake face associated with at least one cutting edge and a first flank face associated with at least one cutting edge, wherein at least one cutting edge is assigned a negative rake angle, a first clearance angle and a wedge angle. It is provided that a value of the negative rake angle in the region of the first cutting edge end has a different value than in the region of the second cutting edge end, that the first clearance angle in the region of the first cutting edge end has a different value than in the region of the second cutting edge end, and that the wedge angle along the cutting edge profile is constant.

A base material for a hard sintered material has a multi-stage columnar shape having a central axis and extending in an axial direction of the central axis. The base material includes a smaller-diameter portion, a larger-diameter portion, a base material end surface located between a one end portion in the axial direction of an outer peripheral surface of the larger-diameter portion and the other end portion in the axial direction of the smaller-diameter portion, and facing toward the one end portion in the axial direction, and a first inclined portion disposed in at least a portion in a circumferential direction of an annular corner portion to which an outer peripheral surface of the larger-diameter portion and the base material end surface are connected. The first inclined portion is located inward in a radial direction toward the one end portion in the axial direction.

A base material for a hard sintered material has a multi-stage columnar shape having a central axis and extending in an axial direction of the central axis. The base material includes a smaller-diameter portion, a larger-diameter portion, a base material end surface located between a one end portion in the axial direction of an outer peripheral surface of the larger-diameter portion and the other end portion in the axial direction of the smaller-diameter portion, and facing toward the one end portion in the axial direction, and a first inclined portion disposed in at least a portion in a circumferential direction of an annular corner portion to which an outer peripheral surface of the larger-diameter portion and the base material end surface are connected. The first inclined portion is located inward in a radial direction toward the one end portion in the axial direction.

A base material for a hard sintered body includes a pillar portion having a central axis and extending in the axial direction of the central axis. The pillar portion has a first outer peripheral portion, a second outer peripheral portion, and a protruding stripe portion. In the cross-sectional view, one side portion of the first outer peripheral portion extending in a circumferential direction or a radial direction is located inside the other side portion. In the cross-sectional view, one side portion of the second outer peripheral portion extending in the circumferential direction or the radial direction is located outside the other side portion in the radial direction. The protruding stripe portion is located in a connection portion between the other side portion of the first outer peripheral portion and one side portion of the second outer peripheral portion, and protrudes outward.

A base material for a hard sintered body includes a pillar portion having a central axis and extending in the axial direction of the central axis. The pillar portion has a first outer peripheral portion, a second outer peripheral portion, and a protruding stripe portion. In the cross-sectional view, one side portion of the first outer peripheral portion extending in a circumferential direction or a radial direction is located inside the other side portion. In the cross-sectional view, one side portion of the second outer peripheral portion extending in the circumferential direction or the radial direction is located outside the other side portion in the radial direction. The protruding stripe portion is located in a connection portion between the other side portion of the first outer peripheral portion and one side portion of the second outer peripheral portion, and protrudes outward.

A milling head for a ball track milling cutter includes an imaginary center axis, a first, working-side end and a second, clamping-side end opposite the first end when viewed along the central axis, and comprising at least one geometrically defined cutting edge, extending along a cutting edge profile of the cutting edge from a first cutting edge end facing the first end of the milling head in the direction of the second end of the milling head up to a second cutting edge end facing the second end of the milling head, wherein at least one cutting edge is formed as an intersecting line between the rake face associated with at least one cutting edge and a first flank face associated with at least one cutting edge, wherein at least one cutting edge is assigned a negative rake angle, a first clearance angle and a wedge angle. It is provided that a value of the negative rake angle in the region of the first cutting edge end has a different value than in the region of the second cutting edge end, that the first clearance angle in the region of the first cutting edge end has a different value than in the region of the second cutting edge end, and that the wedge angle along the cutting edge profile is constant.

A milling head for a ball track milling cutter includes an imaginary center axis, a first, working-side end and a second, clamping-side end opposite the first end when viewed along the central axis, and comprising at least one geometrically defined cutting edge, extending along a cutting edge profile of the cutting edge from a first cutting edge end facing the first end of the milling head in the direction of the second end of the milling head up to a second cutting edge end facing the second end of the milling head, wherein at least one cutting edge is formed as an intersecting line between the rake face associated with at least one cutting edge and a first flank face associated with at least one cutting edge, wherein at least one cutting edge is assigned a negative rake angle, a first clearance angle and a wedge angle. It is provided that a value of the negative rake angle in the region of the first cutting edge end has a different value than in the region of the second cutting edge end, that the first clearance angle in the region of the first cutting edge end has a different value than in the region of the second cutting edge end, and that the wedge angle along the cutting edge profile is constant.

A method for multistep machining a cutting tool includes defining a data set of the cutting tool, positioning the workpiece in a machining device, determining a data set of the workpiece to be machined, defining at least one machining program based on the defined data set in relation to the determined data set of the workpiece, subjecting the workpiece to the at least one machining program, to obtain intermediate geometries of the workpiece, determining a second data set by measuring means including the intermediate geometries of the workpiece and transferring the machined workpiece to a second machining device. Furthermore, the steps of positioning, determining data set of the workpiece, defining machining program, subjecting the workpiece to the machining program, determining a second data set and transferring to the second machining device are repeated until the workpiece takes on the shape of the target geometries.

A method for multistep machining a cutting tool includes defining a data set of the cutting tool, positioning the workpiece in a machining device, determining a data set of the workpiece to be machined, defining at least one machining program based on the defined data set in relation to the determined data set of the workpiece, subjecting the workpiece to the at least one machining program, to obtain intermediate geometries of the workpiece, determining a second data set by measuring means including the intermediate geometries of the workpiece and transferring the machined workpiece to a second machining device. Furthermore, the steps of positioning, determining data set of the workpiece, defining machining program, subjecting the workpiece to the machining program, determining a second data set and transferring to the second machining device are repeated until the workpiece takes on the shape of the target geometries.