A cutting insert (20), comprising:
- two opposing end surfaces (22a, 22b) interconnected by a peripheral side surface (24) and an insert axis (A1) passing through the opposing end surfaces (22a, 22b),
- each end surface (22a, 22b) having a recessed central surface (58),
- the peripheral side surface (24) having two opposing major side surfaces (26a, 26b), two minor side surfaces (28a, 28b), and four convexly curved corner surfaces (42) alternating with the two major side surfaces (26a, 26b) and the two minor side surfaces (28a, 28b),
- a major edge (30) formed at the intersection of each major side surface (26a, 26b) and each end surface (22a, 22b), and a major cutting edge (34) formed along at least a portion of each major edge (30),
- a minor edge (32) formed at the intersection of each minor side surface (28a, 28b) and each end surface (22a, 22b), and a minor cutting edge (36) formed along at least a portion of each minor edge (32),
- a median plane (M) perpendicular to the first insert axis (A1) and intersecting the peripheral side surface (24) to form an insert boundary line (BL), and
- each end surface (22a, 22b) having two diagonally opposed raised corners (RC) and two diagonally opposed lowered corners (LC) with respect to the median plane (M),
- each raised corner (RC) having a convexly curved raised corner edge (46) formed at the intersection of one of said four convexly curved corner surfaces (42) and its associated end surface (22a, 22b), each raised corner edge (46) adjoining one of the major edges (30) at a first major point (NJ1), each raised corner (RC) further having a raised corner cutting edge (50) formed along at least a portion of each raised corner edge (46),
- each lowered corner (LC) having a convexly curved lowered corner edge (48) formed at the intersection of one of said four convexly curved corner surfaces (42) and its associated end surface (22a, 22b), each lowered corner edge (48) adjoining one of the major edges (30) at a third major point (NJ3), each lowered corner edge (48) being entirely located closer to the median plane (M) than its associated central recessed surface (58), each lowered corner (LC) further having a lowered corner cutting edge (52) formed along at least a portion of each lowered corner edge (48),
- wherein in a major side view of the cutting insert (20):
- the first and third major points (NJ1, NJ3) of each major edge (30) define a major side length (SL) measured parallel to the median plane (M), the major side length (SL) being divided into equal first, second and third length portions (L1, L2, L3), in which the first length portion (L1) is delimited by the first major point (NJ1) and the third length portion (L3) is delimited by the third major point (NJ3),
- each major edge (30) has an associated first imaginary straight line (LM1) containing its first and third major points (NJ1, NJ3) and an elevated edge portion (62), the elevated edge portion (62) being located on one side of the first imaginary straight line (LM1) and the insert boundary line (BL) being located on the other side of the first imaginary straight line (LM1), and
- each elevated edge portion (62) has a second major point (NJ2) located:
- (i) furthest from its associated first imaginary straight line (LM1), and (ii) in the third length portion (L3) of its associated major side length (SL).