A cutting insert has an upper surface, a lower surface, a side surface connecting the upper and lower surfaces. An intersecting edge between the upper surface and the side surface is provided with a cutting edge. The cutting edge has, in order, a second major cutting edge, a first major cutting edge, a corner cutting edge connected to these major cutting edges, and a flat cutting edge. An obtuse interior first angle (θ) is formed by the second and first major cutting edges. A interior second angle (α) formed by the flat cutting edge and the first major cutting edge is larger than an interior third angle (β) formed by the flat cutting edge and the second major cutting edge. A land is provided adjacent to the first major cutting edge, a width of the land increasing toward the first corner cutting edge.

A tool for hob peeling rotating workpieces having pre-machined teeth comprises a gear-wheel shaped main body and tooth-shaped cutting inserts (1.2) which at the end face in the region of the tip circle are disposed on the main body. Each cutting insert comprises at least one cutting tooth. The cutting tooth forms a cutting edge (6) which runs at least along one of the flanks of the cutting tooth, and a cutting face and a clearance face. The cutting face along the cutting edge is provided with a cutting face chamfer (7) which in relation to the cutting face (5.5) runs so as to be inclined by a chamfer angle. The chamfer angle varies along the cutting edge. Moreover, the cutting edge is rounded by a radius.

A cutting insert which is excellent in both cutting edge strength and chip evacuation is provided. A corner edge of the cutting insert is formed in an arc shape. In a direction perpendicular to a rotation axis of a body, a width of the corner edge is 40% or more and 50% or less of a width of the cutting insert. An upper surface has a negative land which is formed along a cutting edge and has a negative angle. The angle of the negative land increases from one end, which is connected to an inner cutting edge, of both ends of the corner edge toward the other end.

A cutting insert may include a first surface. The first surface may include a first side, a second side, a first corner, a land surface and an inclined surface. The land surface may include a first land surface, a second land surface and a corner land surface. The first land surface may be located along the first side. The second land surface may be located along the second side. The corner land surface may be located along the first corner. The first land surface may include a part thereof where a first land angle increases as going away from the first corner. The corner land surface may include a part thereof where a corner land angle increases as going away from the first side.

A cutting insert which is excellent in both cutting edge strength and chip evacuation is provided. A corner edge of the cutting insert is formed in an arc shape. In a direction perpendicular to a rotation axis of a body, a width of the corner edge is 40% or more and 50% or less of a width of the cutting insert. An upper surface has a negative land which is formed along a cutting edge and has a negative angle. The angle of the negative land increases from one end, which is connected to an inner cutting edge, of both ends of the corner edge toward the other end.

A cutting insert of one aspect includes a first face, a second face, and a third face. The first face includes a first side, a second side, and a first corner. The first face includes a land face connected to the third face. The land face includes a first land face connected to the first corner, a second land face, and a third land face. The first land face includes a first region connected to the second land face and a second region connected to the third land face. When the first face is viewed from the front, a second width of the second region is larger than a first width of the first region in a front view of the first face.

This cutting insert is provided with a lower surface of polygonal shape including side parts and a pair of corner parts, an upper surface, a lateral surface situated between the lower surface and the upper surface, a pair of corner cutting edges located at the pair of corners, and a main cutting edge located in a side portion. The main cutting edge is upwardly convex in shape, and in side view includes an upwardly convex curving portion, and a pair of linear portions respectively extending toward the pair of corner cutting edges from the curving portion. The top portion of the curving portion is positioned more toward the one of the corner cutting edges which, of the pair of corner cutting edges, is that contiguous to a working surface of a work material during cutting of the work material.

A tool for hob peeling rotating workpieces having pre-machined teeth comprises a gear-wheel shaped main body and tooth-shaped cutting inserts (1.2) which at the end face in the region of the tip circle are disposed on the main body. Each cutting insert comprises at least one cutting tooth. The cutting tooth forms a cutting edge (6) which runs at least along one of the flanks of the cutting tooth, and a cutting face and a clearance face. The cutting face along the cutting edge is provided with a cutting face chamfer (7) which in relation to the cutting face (5.5) runs so as to be inclined by a chamfer angle. The chamfer angle varies along the cutting edge. Moreover, the cutting edge is rounded by a radius.

An indexable cutting insert has upper and lower surfaces with a peripheral surface extending therebetween and having four side surfaces alternating with four corner surfaces. The side and corner surfaces intersect the upper surface to form side and corner cutting edges, respectively. Each side cutting edge includes a primary cutting edge adjoining one of the corner cutting edges at a first endpoint and a secondary cutting edge adjoining another one of the corner cutting edges at a second endpoint. In a top view, the four primary cutting edges define an imaginary first square, each primary cutting edge is tangential to its adjoining corner cutting edge, and each secondary cutting edge is curved and entirely located in one of four imaginary quadrants. The insert is removably secured in a rotary cutting tool such that one of the secondary cutting edges contains the axially forwardmost point of the insert's upper peripheral edge.

A cutting insert has an upper surface (21), a lower surface (91) and a side surface (61) that connects the two surfaces. A cutting edge is formed at an intersecting edge between the upper surface (21) and the side surface (61). The cutting edge includes at least a major cutting edge (33), a corner edge (34) connected to the major cutting edge (33), and a curved wiper edge (35) located on the opposite side of the major cutting edge (33) across the corner edge (34). A first angle made by the major cutting edge (33) and the chord of the wiper edge (35) is 155<180, and a positive land is formed in the wiper edge (35). The cutting edge may further include an inner cutting edge (36) located on an opposite side of the corner edge (34) across the wiper edge (35).