Cutting insert

A tool holder having a longitudinal axis of rotation and a front face formed with at least one insert receiving pocket for receiving therein a cutting insert;

• the at least one insert receiving pocket having a pocket base wall and a pocket rear wall which is disposed at a rear end of the at least one pocket defined with respect to a direction of rotation in which the tool holder is designed to rotate, and is oriented transversely to the pocket base wall and transversely to said direction of rotation;
• the pocket rear wall having two lateral portions connected to a central portion therebetween which is rearwardly depressed relative to the lateral portions and meets therewith via merging edge regions, said lateral portions of the pocket rear wall converging from outer ends thereof in a direction towards a front end of the at least one pocket, wherein
• the pocket base wall is formed with a pocket threaded bore, for receiving therein a clamping screw for securing the cutting insert in said at least one insert receiving pocket, and
• the pocket threaded bore is directed transversely to the longitudinal axis of the tool holder.

A cutting insert comprising:

• a front cutting portion having an operative front surface associated with at least one cutting edge;
• a trailing mounting portion having upper, lower and first and second side walls extending from said front cutting portion to a rear abutment wall, the first and second side walls meeting with said rear abutment wall at respective first and second rear edges, wherein the rear abutment wall comprises:
• a central surface extending in a direction away from the front cutting portion to protrude rearwardly past a reference plane passing through said first and second rear edges, and
• first and second lateral surfaces positioned between the first and second rear edges, respectively and the central surface, each of the first and second lateral surfaces extending in a direction towards the front cutting portion and being positioned between the reference plane and the front cutting portion.

A cutting tool assembly comprising:

• a tool holder having a longitudinal axis of rotation and a front face formed with at least one insert receiving pocket,
• the at least one insert receiving pocket having a pocket base wall and a pocket rear wall which is disposed at a rear end of the at least one insert receiving pocket defined with respect to a direction of rotation in which the tool holder is designed to rotate, and is oriented transversely to the pocket base wall and transversely to said direction of rotation;
• the pocket rear wall having two lateral portions connected to a central portion therebetween which is rearwardly depressed relative to the lateral portions and meets therewith via merging edge regions, said lateral portions of the pocket rear wall converging from outer ends thereof in a direction towards a front end of the at least one pocket;
• and
• a cutting insert seated in said at least one insert receiving pocket, the cutting insert comprising:
• a front cutting portion having an operative front surface associated with at lease one cutting edge;
• a trailing mounting portion having upper, lower and first and second side walls extending from said front cutting portion to a rear abutment wall the first and second side walls meeting with said rear abutment wall at respective first and second rear edges, wherein the rear abutment wall comprises:
• a central surface extending in a direction away from the front cutting portion to protrude rearwardly past a reference plane passing through said first and second rear edges;
• and
• a first and second lateral surfaces positioned between the first and second rear edges, respectively, and the central surface, each of the first and second lateral surfaces extending in a direction towards the front cutting portion and being positioned between the reference plane and the front cutting portion.