A cutting insert includes a rake face, a flank surface, and a cutting edge, the cutting edge includes a bottom cutting edge that is positioned at a front end in a central axis direction and forms a convex arc shape and an outer peripheral cutting edge aligned with a radial-direction outer end of the bottom cutting edge and forms a convex arc shape of which a curvature radius is larger than that of the bottom cutting edge, an angle formed between a tangent line to a boundary point between the bottom cutting edge and the outer peripheral cutting edge and the central axis is less than 45, a curvature radius R1 of the bottom cutting edge is 0.3 to 10 mm, and a ratio (R2/R1) of a curvature radius R2 of the outer peripheral cutting edge to the curvature radius R1 of the bottom cutting edge is 3.6 to 333.

In a cutting insert according to an embodiment of the present invention, an upper cutting edge includes, sequentially from a first corner to a second corner, a corner cutting edge, a minor cutting edge inclined as separating from the corner cutting edge at a first inclination angle on a basis of a vertical plane perpendicular to a central axis extending between upper and lower surfaces, and a major cutting edge inclined as separating from the minor cutting edge at a second inclination angle on the basis of the vertical plane so as to become more closer to the lower surface than the minor cutting edge. A cross section of a rake surface obtained by cutting an inwardly located end portion thereof along a direction of the central axis has a straight line shape or concave shape in a region crossing over at least a minor rake surface and a major rake surface. A cutting tool with the cutting insert, and a method of manufacturing a machined product by using the cutting tool are also provided.

A cutting insert of an embodiment includes an upper surface including a first upper cutting edge and a second upper cutting edge, a lower surface including a first lower cutting edge and a second lower cutting edge, and a side surface. The side surface includes a first surface extending from the second upper cutting edge, a second surface extending from the first lower cutting edge, a third surface extending from the first upper cutting edge, and a fourth surface extending from the second lower cutting edge. The first surface and the fourth surface are parallel to a central axis. The second surface is inclined so as to depart from the central axis as going from the lower surface toward the upper surface. The third surface is inclined so as to depart from the central axis as going from the upper surface toward the lower surface.

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.

A cutting tool may include a cutter body, and a cutting insert group coupled to the cutter body, wherein the cutter body includes a working length, wherein the cutting insert group forms a continuous cutting edge, and wherein the continuous cutting edge extends continuously through the working length of the cutter body.

A cutting insert includes a rake end surface having four corners and, in a center thereof, a central surface portion. A supporting end surface has four corners and, in a center thereof, a central supporting surface portion. A peripheral side surface extends between the rake end surface and the supporting end surface. The peripheral side surface includes two opposing major side surfaces. A hole extends through the cutting insert from one of the major side surfaces to the other of the major side surfaces, wherein the central surface portion is disposed at a greater distance from a central axis (A) of the hole than is the central supporting surface portion. The single-sided cutting insert has a corner radii or cutting edge radii that extend over at least a quarter of a width of the cutting insert.

A cutting insert (1) according to an embodiment has a lower surface (2), an upper surface (3), a side surface (4) disposed between the lower surface (2) and the upper surface (3), a pair of corner cutting edges (5) located along an intersection of the upper surface (3) and the side surface (4), and a major cutting edge (6) located between the pair of corner cutting edges (5). The major cutting edge (6) has a downwardly dented curvilinear part (61) and a pair of straight parts (62) respectively extending from the curvilinear part (61) toward the pair of corner cutting edges (5) in a side view. A portion (6p) of the curvilinear part (61) located lowermost is close to one corner cutting edge (5b) in the side view.

An insert includes a first part and a second part. The first part includes a first surface, a second surface, and a plurality of side surfaces located between the first surface and the second surface. The second part includes a third surface, a fourth surface, and a first cutting edge. The third surface is located between the side surfaces and located from a side of the first surface to a side of the second surface. The fourth surface is located between the side surfaces and adjacent to the third surface. The first cutting edge is located along at least a part of a ridge line of the third surface and the fourth surface. The first cutting edge is inclined in a front view of the third surface, and the first cutting edge has a convex curvilinear shape in a front view of the fourth surface.

A round double-sided cutting insert includes an insert peripheral surface that includes a plurality of angularly spaced apart indexing latches protruding therefrom and a plurality of cylindrical insert side abutment surfaces that circumferentially alternate with the plurality of indexing latches. An insert holder has a pocket peripheral surface which includes at least one indexing gap and a plurality of pocket side abutment surfaces that circumferentially alternate with the at least one indexing gap. When the cutting insert is releasably attached to the insert holder, to constitute a fastened position of a cutting tool, each of the plurality of pocket side abutment surfaces abuts a respective insert side abutment surface and each indexing gap has a respective indexing latch located therein.

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.