An indexable milling or drilling insert having a 180-degree rotational symmetry about each of the first, second and third axes (X, Y, Z) of a three-dimensional euclidean space. The insert has opposite first and second main surfaces and a peripheral surface extending therebetween. Each main surface has a main abutment surface and at least two rake surfaces. The insert has a through clamping bore which extends along the third axis and opens out to the main surfaces. The peripheral surface has two opposite front surfaces connected to two opposite side surfaces. Each front surface has a pair of outward abutment surfaces and each side surface has a pair of at least partially planar inward abutment surfaces. Each pair of outward abutment surfaces converge outwardly away from the third axis and each pair of inward abutment surfaces converge inwardly towards the third axis.

An indexable milling or drilling insert having a 180-degree rotational symmetry about each of the first, second and third axes (X, Y, Z) of a three-dimensional euclidean space. The insert has opposite first and second main surfaces and a peripheral surface extending therebetween. Each main surface has a main abutment surface and at least two rake surfaces. The insert has a through clamping bore which extends along the third axis and opens out to the main surfaces. The peripheral surface has two opposite front surfaces connected to two opposite side surfaces. Each front surface has a pair of outward abutment surfaces and each side surface has a pair of at least partially planar inward abutment surfaces. Each pair of outward abutment surfaces converge outwardly away from the third axis and each pair of inward abutment surfaces converge inwardly towards the third axis.

A drill bit for cutting formation comprises a bit body, a plurality of cutters, and a plurality of blades with pockets to accommodate the cutters, respectively. In an embodiment, the plurality of cutters comprise a substrate, an ultra-hard layer, a concave surface on the top of the ultra-hard layer, wherein the concave surface comprises a plurality of planar and curved surfaces.

A cutting insert including a first end surface, a second end surface and a peripheral side surface extending therebetween. The first and second end surfaces each having one substantially quadrangular portion and two substantially semicircular portions which are respectively joined to two opposing sides of the substantially quadrangular portion. An intersecting edge between each of the first and second end surfaces and the peripheral side surface is provided with a cutting edge. The cutting edge is formed in at least part of the substantially semicircular portion. At least part of a portion of the peripheral side surface which is adjacent to the substantially quadrangular portion of each of the first and second end surfaces, and at least part of a portion of the peripheral side surface which is adjacent to the substantially semicircular portion, each have a function of coming into contact with an insert seat.

The present invention provides a cutting insert in which suitable honing is formed on a cutting edge. The cutting insert is provided with: two end surfaces opposing each other; a peripheral side surface extending between the two end surfaces; and a cutting edge formed on an intersecting ridge between at least one of the two end surfaces and the peripheral side surface. The cutting edge at least includes a major cutting edge and an inner cutting edge. Honing is provided on the major cutting edge and the inner cutting edge. A width of second honing of the inner cutting edge is narrower than a width of first honing of the major cutting edge, as viewed from a side of the end surfaces.

A cutting insert according to an embodiment has a polygonal shaped upper surface, a lower surface, a side surface, and a cutting edge. The cutting edge has an arc-shaped first corner edge, an arc-shaped second corner edge, and a wiper edge located between the first corner edge and the second corner edge. The wiper edge has an arc-shaped first wiper edge and an arc-shaped second wiper edge located closer to the second corner edge than the first wiper edge. R0<R1<R2 is satisfied wherein R1 is a radius of curvature of the first wiper edge, R2 is a radius of curvature of the second wiper edge, and R0 is a radius of curvature of each of the corner edges in a top view.

An indexable cutting insert for face milling with high feed rates has: an upper side, a lower side with a smaller outer circumference than the upper side, and side surfaces connecting the upper and lower sides. Rounded cutting corners are formed at the transition between the side surfaces and the upper side. The cutting corners are connected via convexly arched cutting edges, each running convexly curved from one cutting corner to an adjacent cutting corner. Adjacent the cutting edges, the side surfaces have main flanks extending along the respective cutting edge in a continuously convexly curved manner from one cutting corner to an adjacent cutting corner. The main flanks extend in the direction of the lower side only over part of the height of the side surfaces and merge in a stepped manner into secondary surfaces which are set back inward.

A cutting insert according to an embodiment has a lower surface, an upper surface, a side surface disposed between the lower surface and the upper surface, a pair of corner cutting edges located along an intersection of the upper surface and the side surface, and a major cutting edge located between the pair of corner cutting edges. The major cutting edge has a downwardly dented curvilinear part and a pair of straight parts respectively extending from the curvilinear part toward the pair of corner cutting edges in a side view. A portion of the curvilinear part located lowermost is close to one corner cutting edge in the side view.

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.

A cutting insert according to an embodiment has a polygonal shaped upper surface, a lower surface, a side surface, and a cutting edge. The cutting edge has an arc-shaped first corner edge, an arc-shaped second corner edge, and a wiper edge located between the first corner edge and the second corner edge. The wiper edge has an arc-shaped first wiper edge and an arc-shaped second wiper edge located closer to the second corner edge than the first wiper edge. R0<R1<R2 is satisfied wherein R1 is a radius of curvature of the first wiper edge, R2 is a radius of curvature of the second wiper edge, and R0 is a radius of curvature of each of the corner edges in a top view.