Rhombus-shaped reversible cutting insert and support seat therefor

An assembly (20) of a generally rhombus-shaped reversible cutting insert (22) and a support seat (24), wherein:

• the cutting insert (22) comprises:
• two opposing end surfaces (26) interconnected by a continuous peripheral side surface (28), the peripheral side surface (28) having alternating obtuse and acute corner surfaces (30, 32) separated by four side surfaces (34);
• a median plane (M) located between the two opposing end surfaces (26) and intersecting the peripheral side surface (28), an insert axis (A1) perpendicular to the median plane (M) and about which the cutting insert (22) is indexable, a nose cutting edge (36) formed at the intersection of each acute corner surface (32) and each end surface (26), a longitudinal plane (P1) containing the insert axis (A1) and bisecting the four nose cutting edges (36), a nose point (N1) located at the intersection of each nose cutting edge (36) and the longitudinal plane (P1) and a lateral plane (P2) containing the insert axis (A1) and bisecting the two obtuse corner surfaces (30),
• each end surface (26) having a corner abutment surface (38) adjacent each nose cutting edge (36) and a rake surface (48) located therebetween, at least one inner abutment surface (40a, 40b) entirely located on one side of the lateral plane (P2), and at least one inner abutment surface (40a, 40b) entirely located on the opposite side of the lateral plane (P2), and
• each corner abutment surface (38) located closer to the median plane (M) than its adjacent nose point (N1),
• the support seat (24) comprises a seat surface (42) with a plurality of supporting members (44a, 44b, 44c) protruding therefrom, each supporting member (44a, 44b, 44c) having a supporting surface (46a, 46b, 46c) in contact with the end surface (26) facing the support seat (24),
• wherein in a cross-sectional view of the cutting insert (22) taken along the longitudinal plane (P1), a first imaginary straight line (L1) containing any one of the nose points (N1) and a radially outermost point (NO) of the adjacent corner abutment surface (38) forms an acute first angle (β1) greater than 25° with the median plane (M);
• and
• wherein in each index position of the cutting insert (22):
• only one of the two corner abutment surfaces (38) of the end surface (26) facing the support seat (24) is in operative contact with the support seat (24), at a first supporting surface (46a), and
• only the at least one inner abutment surface (40a, 40b) of the end surface (26) facing the support seat (24) located on the opposite side of the lateral plane (P2) from the operative corner abutment surface (38) is in contact with the support seat (24) at the at least one remaining supporting surface (46b, 46c).

A generally rhombus-shaped reversible cutting insert (22) comprising:

• two opposing end surfaces (26) interconnected by a continuous peripheral side surface (28), the peripheral side surface (28) having alternating obtuse and acute corner surfaces (30, 32) separated by four side surfaces (34);
• a median plane (M) located between the two opposing end surfaces (26) and intersecting the peripheral side surface (28),
• an insert axis (A1) perpendicular to the median plane (M) and about which the cutting insert (22) is indexable,
• a nose cutting edge (36) formed at the intersection of each acute corner surface (32) and each end surface (26),
• a longitudinal plane (P1) containing the insert axis (A1) and bisecting the four nose cutting edges (36),
• each end surface (26) having a corner abutment surface (38) adjacent each nose cutting edge (36) and a rake surface (48) located therebetween,
• a nose point (N1) located at an intersection of each nose cutting edge (36) and the longitudinal plane (P1), and
• each corner abutment surface (38) located closer to the median plane (M) than its adjacent nose point (N1),
• wherein:
• no point on each end surface (26) is located further from the median plane (M) than the two nose points (N1) associated therewith,
• the median plane (M) intersects each side surface (34) to form a side boundary line (LS), two side boundary lines (LS) converge towards the same acute corner surface (32) to form an acute nose corner angle (α1) which is less than 60°, and
• in a cross-sectional view of the cutting insert (22) taken along the longitudinal plane (P1), a first imaginary straight line (L1) containing any one of the nose points (N1) and a radially outermost point (NO) of the adjacent corner abutment surface (38) forms an acute first angle (β1) greater than 25° with the median plane (M).