A cutting tool includes: a body extending along a longitudinal axis between a leading and trailing ends, the body having a clamping region disposed at or about the trailing end and a cutting region which extends toward the clamping region from the leading end of the body; a plurality of flutes defined in the body, each extending from the leading end toward the coupling portion; a plurality of peripheral cutting edges, each extending from the leading end toward the coupling portion along a corresponding flute of the plurality of flutes; and a plurality of end cutting edges disposed at the leading end, each end cutting edge extending from at or near the longitudinal axis outward along a corresponding flute. At least one end cutting edge is defined, in-part, by a plurality of rake faces which each extend from a corresponding portion of the one cutting edge into the corresponding flute.

A ball end mill comprises a gash provided at a front end portion of a main end mill body rotated about an axis; and at least one cutting edge which has a rotational trajectory around the axis that forms a convex hemispherical shape having a center on the axis. The cutting edge is formed at a peripheral edge portion of a wall surface of the gash. A difference between a first and second included angles is within ±7°, where the first included angle is formed between the axis and a straight line connecting the center with a cutting edge position at which a depth of the gash is maximal in a cross-section orthogonal to the cutting edge, and the second included angle is formed between the axis and a straight line connecting the center with a cutting edge position at which a rake angle of the cutting edge is maximal.

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.

An insert is provided, ensuring to vary the cutout angle of the cutting edge without replacing the body, and to prevent the change in the cutout angle of the cutting edge in the cutting process. The insert includes a constraining part, a through hole, and a blade. The blade includes a cutting edge for the cutting process. An outer surface of the constraining part around the central axis includes a pair of first constraining surfaces, and a pair of second constraining surfaces. The cutting edge in the state where the pair of first constraining surfaces are fixed becomes non-parallel to the cutting edge in the state where the constraining part is rotated around the central axis from the fixed state of the pair of first constraining surfaces to place the pair of second constraining surfaces on the same surface on which the pair of first constraining surfaces have been fixed.

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 cutter head structure includes a cutting edge portion including a cutting body. An outer surface of the cutting body is a curved surface which protrudes forwardly. The outer surface of the cutting body is provided with a first cutting edge and at least two second cutting edges. The first cutting edge extends from one side of the cutting body to a top region of the cutting body and then to the other side of the cutting body. The second cutting edges are respectively disposed on both sides of the first cutting edge. First chip flutes are defined between the first cutting edge and the second cutting edges adjacent thereto, and each of the first chip flutes has a width gradually increasing from the top region to both ends of the cutting body.

Chip breaking features may be arranged in radial reliefs of a rotary cutting tool. The chip breaking features create gaps or voids in the otherwise continuous cutting edge, resulting in otherwise continuous chips being cut into discrete chips. The chip breaking features may be angled so as to define a secondary cutting edge. Depending on the angle at which the chip breaking features are angled, the secondary cutting edges may partially or completely close the gaps or voids in the cutting edge. Closing the gaps or voids in the cutting edge ensures that each blade removes nearly all material so the following blade does not have to clean up.

An insert is provided, ensuring to vary the cutout angle of the cutting edge without replacing the body, and to prevent the change in the cutout angle of the cutting edge in the cutting process. The insert includes a constraining part, a through hole, and a blade. The blade includes a cutting edge for the cutting process. An outer surface of the constraining part around the central axis includes a pair of first constraining surfaces, and a pair of second constraining surfaces. The cutting edge in the state where the pair of first constraining surfaces are fixed becomes non-parallel to the cutting edge in the state where the constraining part is rotated around the central axis from the fixed state of the pair of first constraining surfaces to place the pair of second constraining surfaces on the same surface on which the pair of first constraining surfaces have been fixed.

An indexable roughing end mill capable of suppressing generation of chattering is provided. When the positions of cutting inserts (40) arranged in each spiral groove (28) are defined as a first segment to an n.sup.th segment (where n is an integer of 2 or higher) from a leading end surface (22) side of a tool body (20) toward a base end surface (21) side, all of the angles (1 . . . m (where m is an integer of 2 or higher)) between lines connecting a rotational axis (O) and the cutting inserts (40) in the first segments of the respective spiral grooves (28) are different from each other, as viewed from the leading end surface side of the tool body (20), and an angle (t) between the cutting insert (40) in the first segment and the cutting insert (40) in the n.sup.th segment (the uppermost segment) in a spiral groove 28 is different from any of the angles 1 . . . m (where m is an integer of 2 or higher) between the lines, as viewed from the leading end surface side of the tool body (20).