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 insert detachably attached to an indexable rotary cutting tool, having an upper surface having cutting edges along the ridgeline, a lower surface, side surfaces, and a center hole for a fastening screw; each cutting edge having a corner cutting edge formed in each acute corner portion, and a bottom cutting edge and a peripheral cutting edge formed along the ridgelines on both sides of the corner cutting edge; the bottom cutting edge and the peripheral cutting edge having different clearance angles; a flank of the corner cutting edge having an angle-changing surface portion having a clearance angle continuously changing in a region from the bottom cutting edge to the peripheral cutting edge; and the length of the peripheral cutting edge being restricted by a receding portion adjacent to an upper end of the peripheral cutting edge.

An indexable rotary cutting tool comprising, a twist angle of the outer peripheral cutting edge having a positive value, an axial rake angle of the cutting edge of the corner R at a boundary point between the cutting edge of the corner R and the outer peripheral cutting edge has a positive value, the axial rake angle of the cutting edge of the corner R at the reference point has a negative value, at least the radial rake angle in a region between the boundary point and the reference point in an entire edge length region of the cutting edge of the corner R has a negative value, and the radial rake angle of the cutting edge of the corner R at the reference point is smaller than the radial rake angle of the cutting edge of the corner at the boundary point.

A double-sided, indexable, non-positive ramping insert has a 180-degree rotational symmetry about each of the first, second and third axes of a three-dimensional Euclidean space. The ramping insert includes two first surfaces and an insert peripheral surface which extends therebetween. The ramping insert includes four cutting portions, each includes a major cutting edge, a wiper edge connected transversely thereto via a corner cutting edge and a ramping edge which extends transversely from the wiper edge in a view parallel to the first axis. Each peripheral surface includes four non-positive ramping relief surfaces, each of which extends from a respective ramping edge towards, and not beyond, a first median plane which is defined by the second and third axes.

A double-sided, indexable, non-positive ramping insert has a 180-degree rotational symmetry about each of the first, second and third axes of a three-dimensional Euclidean space. The ramping insert includes two first surfaces and an insert peripheral surface which extends therebetween. The ramping insert includes four cutting portions, each includes a major cutting edge, a wiper edge connected transversely thereto via a corner cutting edge and a ramping edge which extends transversely from the wiper edge in a view parallel to the first axis. Each peripheral surface includes four non-positive ramping relief surfaces, each of which extends from a respective ramping edge towards, and not beyond, a first median plane which is defined by the second and third axes.