A cutting insert for a milling tool, having a first side, a second side which is identical to the first side and a circumferential surface which extends between the first and the second sides, with a bore which extends along a bore axis. The cutting insert is 120 rotationally symmetrical with respect to the bore axis and includes on each of the first side and the second side three identically formed cutting regions, respectively, which are situated at a transition between the first side and the circumferential surface or at a transition between the second side and the circumferential surface, respectively. Each of the in total six cutting regions includes a first rectilinear cutting edge, a second rectilinear cutting edge, and a third arcuate cutting edge, wherein a first end of the first cutting edge is connected to a first end of the third cutting edge, and a first end of the second cutting edge is connected to a second end of the third cutting edge, wherein the first and the second cutting edges are of same length. The cutting insert includes on the first side a first contact surface which extends orthogonally to the bore axis and lies in a first contact plane, and on the second side includes a second contact surface which extends orthogonally to the bore axis and lies in a second contact plane, and wherein each of the first cutting edges are connected at their second ends, which are located opposite the first ends, to one of a total of six arcuate edges, a vertex of which is located between the first and the second contact planes.

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.

An indexable cutting insert has opposing upper and lower end surfaces, and a peripheral surface including three side surfaces circumferentially alternating with three corner surfaces. The three side surfaces define an imaginary triangle and an imaginary hexagon. Each corner surface intersects the upper end surface to form an upper corner peripheral edge having a primary cutting edge. In a top view, each triangle side traverses two upper corner peripheral edges, imaginary lines tangential to the end points of each primary cutting edge are either collinear or form an obtuse angle greater than 175 degrees, each primary cutting edge has a primary length greater than half the hexagon side length, and at least one triangle side traverses each primary cutting edge. The insert is removably secured in a rotary cutting tool such that one of the upper corner peripheral edges contains an axially forwardmost point of the insert's upper peripheral edge.

Provided is a cutting insert capable of suppressing edge fracture when a work having high hardness is machined. A cutting insert includes two end surfaces having a plurality of corner parts and opposed to each other, a peripheral side surface extending between the two end surfaces, and a cutting edge formed at an intersecting edge between at least one of the two end surfaces and the peripheral side surface. The cutting edge has at least a first corner edge, a second corner edge, a major cutting edge, and an end cutting edge. The end cutting edge has a circular-arc shape, which projects outward, as viewed from the side of the end surface. The end cutting edge has a width which is from 15% to 50% of the width of the cutting insert. The end cutting edge has an arc radius which is from to 1/1 of the width of the cutting insert.

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 cutting insert for a shoulder milling tool has a trigonal shape and includes a first surface, a second surface, and a circumferential surface extending between the first surface and the second surface. The circumferential surface includes a countersunk circumferential waist portion. The circumferential surface has a first and a second clearance surface extending along a first and a second main cutting edge. Each of the first and second clearance surfaces forma a negative nominal clearance angle. Each of the first and second main cutting edges is arranged inside the countersunk circumferential waist portion, as seen in the view towards the first and second surfaces, respectively.

A second distance is longer than a first distance and a value obtained by dividing the third distance by the fourth distance is more than or equal to 0.5 and less than or equal to 0.8 when it is assumed that the first distance represents a distance between the cutting edge and the mounting surface in a direction perpendicular to the rake face, the second distance represents a distance between the mounting surface and a boundary portion between the rising portion and the flat portion in the direction perpendicular to the rake face, the third distance represents a distance between the boundary portion and a tip of the cutting edge in a direction parallel to the rake face, and the fourth distance represents a distance between the second discharging opening portion and the tip of the cutting edge in the direction parallel to the rake face.

A cutting insert and a shoulder milling tool are disclosed. The cutting insert includes a surface-wiping secondary cutting edge inclined in relation to a median plane of the cutting insert such that a distance to the median plane decreases in a direction toward a corner cutting edge. The corner cutting edge, as seen in a side view along the median plane and towards a main cutting edge, has a concave curve.

The cutting edge has: a corner cutting edge; a flat cutting edge continuous to a first end portion of the corner cutting edge; and a main cutting edge continuous to a second end portion of the corner cutting edge opposite to the first end portion of the corner cutting edge. The rake face has: a first rising surface portion; and a first rake face portion continuous to the first rising surface portion and located opposite to the corner cutting edge when viewed from the first rising surface portion. When viewed in a direction perpendicular to the reference surface, the first boundary includes a first line segment extending, from one of the flat cutting edge and the corner cutting edge, in a direction crossing a straight line extending along the main cutting edge.

A milling insert, including an upperside, an underside, and a reference plane parallel thereto. A plurality of indexable cutting edges are formed along a peripheral borderline in transitions between at least the upperside and a number of clearance surfaces. Each cutting edge includes a chip-removing main edge and a surface-wiping secondary edge. The main edge, from a first end of the main edge adjacent to the secondary edge, first declines toward the underside of the milling insert and then, from a lowest part, rises toward an opposite second end of the main edge. The secondary edge is inclined at an angle () in relation to the reference plane as viewed perpendicularly to the clearance surface of the secondary edge, such that a first end of the secondary edge connected to the main edge is situated on a lower level than the opposite, second end of the secondary edge.