A front and back chamfering rotary milling cutter includes a cutter body including an insert pocket and a star-shaped indexable cutting insert releasably retained in the pocket. The cutting insert has star-shaped upper and lower surfaces connected by a peripheral surface intersecting each of the upper and lower surfaces. The cutting insert includes a plurality of circumferentially alternating inner and outer corner portions. A cutting portion is defined by each outer corner portion together with an adjacent first inner corner portion rotationally forward thereof and an adjacent second inner corner portion located rotationally rearward thereof. Each cutting portion includes a front chamfering cutting edge extending from the outer corner portion to the first inner corner portion and a back chamfering cutting edge extending from the outer corner portion to the second inner corner portion.

A cutting insert includes a body portion having an upper surface, a lower surface located opposite the upper surface, and side surfaces extending between the upper surface and the lower surface. The body portion disposed about an axis passing through the upper and lower surfaces. The cutting insert further including a plurality of projecting portions provided integrally with the body portion at an outer position thereof in a direction orthogonal to the axis. Each projecting portion has an upper and lower surface, two side surfaces, a side end surface extending between the side surfaces, a round corner surface extending between the upper and side end surfaces, and a cutting edge formed between at least one of the side surfaces and the side end surface. The side surface of each projecting portion is structured to engage a first or second contact surface of a mounting seat formed in a cutter body.

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 front and back chamfering rotary milling cutter includes a cutter body including an insert pocket and a star-shaped indexable cutting insert releasably retained in the pocket. The cutting insert has star-shaped upper and lower surfaces connected by a peripheral surface intersecting each of the upper and lower surfaces. The cutting insert includes a plurality of circumferentially alternating inner and outer corner portions. A cutting portion is defined by each outer corner portion together with an adjacent first inner corner portion rotationally forward thereof and an adjacent second inner corner portion located rotationally rearward thereof. Each cutting portion includes a front chamfering cutting edge extending from the outer corner portion to the first inner corner portion and a back chamfering cutting edge extending from the outer corner portion to the second inner corner portion.

A cutting insert having a first coupling structure, a tool holder having a complementary second coupling structure with a seat for a milling tool system, and a milling tool system having a cutting insert and a holder are all described. The first coupling structure has a circular cylindrical element with a cylinder abutment surface, the circular cylindrical element projecting axially from a bottom surface of a central body and being arranged concentrically with respect to a central axis, A perpendicular abutment surface is arranged perpendicular to the central axis, and at least two ribs project axially from the bottom surface. Each rib has a contact area with a normal direction at least essentially perpendicular to the central axis for opposing a torque about the central axis.