A cutting insert includes a main body including a first face, a second face, and a third face. The second face includes a rake face. Among the outer-peripheral sides of the second face, the boundary portion with the first face is a main cutting edge. When viewed from the side where the first face is disposed, the main cutting edge includes a first straight portion, a second straight portion, and a curved portion. The first straight portion is located adjacent to a reference side. The second straight portion is arranged at a distance from the first straight portion. The curved portion connects the first straight portion and the second straight portion. A first intersection angle of the first straight portion with respect to the reference side is different from a second intersection angle of the second straight portion with respect to the reference side.

A reversible cutting insert for milling including opposing and identically or substantially identically top and bottom surfaces interconnected by a continuous peripheral side surface, with a median plane located between the top and bottom surfaces and intersecting the side surface, and an insert axis perpendicular to the median plane about which the cutting insert is indexable. Each top and bottom surface is limited by a circumferential cutting edge intersecting the side surface, the circumferential cutting edge in a top view having the shape of a truncated equilateral triangle. Each circumferential cutting edge includes three analogous sets of cutting edges exhibiting three-fold rotational symmetry about the insert axis. A first cutting edge portion intersects a first support plane.

A cutting insert of the present disclosure includes a top surface, a bottom surface, a side surface, and a corner cutting edge, a first cutting edge, a second cutting edge and a third cutting edge formed at a ridge line formed by the side surface and the top surface. The corner cutting edge has a first end and a second end. The first cutting edge extends from the first end in a first direction. The second cutting edge extends from the second end in a second direction. The third cutting edge extends from the second cutting edge in a third direction. The top surface has a first rake face adjacent to the first cutting edge, a second rake face adjacent to the second cutting edge, and a third rake face adjacent to the third cutting edge.

A ridgeline between the top surface and the side surface includes: a nose cutting edge portion having a curved line shape, the nose cutting edge portion having a first end and a second end opposite to the first end; a major cutting edge portion contiguous to the first end; and a wiper cutting edge portion contiguous to the second end. The top surface includes: a first rake face contiguous to the wiper cutting edge portion; a second rake face contiguous to the major cutting edge portion; and a third rake face contiguous to the nose cutting edge portion and contiguous to each of the first rake face and the second rake face. A boundary line between the second rake face and the third rake face is separated from the first end and is contiguous to the major cutting edge portion.

A cutting insert includes a main body including a first face, a second face, and a third face. The second face includes a rake face. Among the outer-peripheral sides of the second face, the boundary portion with the first face is a main cutting edge. When viewed from the side where the first face is disposed, the main cutting edge includes a first straight portion, a second straight portion, and a curved portion. The first straight portion is located adjacent to a reference side. The second straight portion is arranged at a distance from the first straight portion. The curved portion connects the first straight portion and the second straight portion. A first intersection angle of the first straight portion with respect to the reference side is different from a second intersection angle of the second straight portion with respect to the reference side.

A cutting insert for a rotary cutting tool has a second surface that includes a second seating surface having a shape of a flat surface. The first cutting edge has a first main cutting edge portion and a first sub cutting edge portion. The second cutting edge has a second main cutting edge portion and a second sub cutting edge portion. When viewed in a direction from the first surface toward the second surface, at least a portion of the second sub cutting edge portion is located outside the first main cutting edge portion, and at least a portion of the first sub cutting edge portion is located outside the second main cutting edge portion. When viewed in the direction from the first surface toward the second surface, each of the first sub cutting edge portion and the second sub cutting edge portion has a shape of a curved line.

A double-sided, indexable cutting insert for a milling cutter includes a first surface, a second surface, and side surfaces. Cutting edges are defined at an intersection between the first and second surfaces and side surfaces. Each cutting edge includes a first cutting-edge portion, a second cutting-edge portion and a third cutting-edge portion. The first and second surfaces include diagonally opposite recessed regions. The cutting insert is mounted in a milling cutter defining a radial rake angle, A, and a ramping angle, B, with respect to a central, rotational axis of the milling cutter that provide superior performance for both milling and ramping cutting operations.

A cutting insert is mountable on a body. The cutting insert includes: a top surface; a bottom surface opposite to the top surface; a side surface contiguous to the top surface and the bottom surface; and a cutting edge formed at a ridgeline between the top surface and the side surface. The side surface has a first surface disposed adjacent to the cutting edge and a second surface contiguous to the first surface. When viewed in a cross sectional view parallel to the bottom surface, the second surface has a first position and a second position that are brought into abutment with the body when mounted on the body. Between the first position and the second position, an imaginary straight line extending through the first position and the second position is separated from the second surface.

A cutting insert for a milling tool including an upper side having a central surface, a lower side, a peripheral side surface, and a cutting edge formed between the upper side and the peripheral side surface. The cutting edge having a positively inclined main cutting edge projecting at least partly above the central surface. The upper side includes a rake surface extending inside of and along the at least one cutting edge, sloping downward toward the central surface. A plateau, elevated with respect to the central surface and extending along the main cutting edge, is formed inside the rake surface. A transition between the rake surface and the plateau extends at an angle .sub.2 with respect to an upper extension plane, wherein .sub.2>0.