Cutting insert having a rearwardly offset cutting edge and cutting tool

A cutting tool (20) comprising, in combination:

• a cutting insert (22) having an insert longitudinal axis (A), the cutting insert (22) comprising:
• opposing forward and rear surfaces (34, 36) and a peripheral surface (28) extending therebetween, the peripheral surface (28) comprising opposing side surfaces (26) connecting opposing upper and lower surfaces (38, 40);
• and
• an insert through bore (30) passing through the side surfaces (26) along a side axis (S);
• wherein:
• the forward and upper surfaces (34, 38) intersect to form a main cutting edge (42) having an associated relief surface (44) that extends therefrom in the forward surface (34);
• one of the side surfaces (26) comprises an insert side abutment surface (60);
• the rear surface (36) comprises an insert rear abutment surface (50);
• the lower surface (40) comprises an insert lower abutment surface (52);
• and
• the insert rear and lower abutment surfaces (50, 52) form an obtuse abutment angle (α) with respect to each other;
• and
• an insert holder (24), having a holder longitudinal axis (B), comprising:
• a holder forward end surface (72) and a holder peripheral surface (74) forming a circumferential boundary thereof;
• an insert pocket (76) recessed in the holder peripheral surface (74) and opening out to the holder forward end surface (72), the insert pocket (76) comprising:
• a pocket side surface (78) and a pocket peripheral wall surface (80) oriented substantially perpendicularly thereto, the pocket side surface (78) comprising a pocket side abutment surface (82), and the pocket peripheral wall surface (80) comprising pocket rear and lower abutment surfaces (86, 88);
• wherein in an assembled position of the cutting tool (20):
• the cutting insert (22) is removably attached to the insert holder (24) by a fastening member (32);
• the pocket lower abutment surface (88) abuts the insert lower abutment surface (52), the pocket rear abutment surface (86) abuts the insert rear abutment surface (50) and the pocket side abutment surface (82) abuts the insert side abutment surface (60);
• a forwardmost abutment point (PF) is defined between the insert lower abutment surface (52) and the pocket lower abutment surface (88) furthest from the rear surface (36);
• and
• in a side view of the cutting tool (20) along the side axis (S), the main cutting edge (42) is offset in a direction towards the rear surface (36) relative to the forwardmost abutment point (PF), as measured along the insert longitudinal axis (A).

An indexable cutting insert (22) having an insert longitudinal axis (A), the cutting insert (22) comprising:

• opposing forward and rear surfaces (34, 36) and a peripheral surface (28) extending therebetween, the peripheral surface (28) comprising opposing side surfaces (26) connecting opposing upper and lower surfaces (38, 40);
• and
• an insert through bore (30) passing through the side surfaces (26) along a side axis (S) around which the cutting insert has 180° rotational symmetry;
• wherein:
• the forward and upper surfaces (34, 38) intersect at a first insert cutting corner (66) to form a first main cutting edge (42) having an associated rake surface (48) in the upper surface (34) and an associated relief surface (44) in the forward surface (34);
• the rear and lower surfaces (36, 40) intersect at a second insert cutting corner (66) to form a second main cutting edge (42′) having an associated rake surface (48) in the lower surface (36) and an associated relief surface (44) in the rear surface (34);
• the cutting insert has a generally parallelogram-shape in a view along the side axis (S);
• and
• the generally parallelogram-shape includes a short diagonal (D1) connecting the insert cutting corners (66) and a long diagonal (D2) connecting insert non-cutting corners (65).