Patent ID: 8875606

Claim:
A modular cutting tool holder portion ( 16 , 18 ) for a metal-working machine, comprising a four-way indexable first engagement face ( 32 , 106 ) configured for clamping engagement with a corresponding four-way indexable second engagement face of a complementary modular cutting tool holder portion ( 18 , 16 ); the first engagement face ( 32 , 106 ) comprising a base surface ( 48 , 132 ) and interlocking elements ( 50 , 134 ) in the form of exactly four projecting protrusions ( 50 ) or exactly four recesses ( 134 ); each interlocking element ( 50 , 134 ) comprising a non-contact surface ( 68 , 148 ) spaced from the base surface ( 48 , 132 ) and having two opposing edges ( 70 , 72 , 150 , 152 ) between which it extends, and two abutment surfaces ( 74 , 76 , 154 , 156 ) each extending from a respective one of the two opposing edges ( 70 , 72 , 150 , 152 ) to the base surface ( 48 , 132 ) and being configured for the clamping engagement; wherein: each protrusion ( 50 ) or recess ( 134 ) has a first end ( 56 , 138 ) located at an intersection ( 58 , 140 ) of the first engagement face ( 32 , 106 ) with an external peripheral surface ( 30 , 118 ) of the modular tool holder portion; and each protrusion ( 50 ) or recess ( 134 ) extends from the first end ( 56 , 138 ) to a second end ( 60 , 142 ) disposed along the first engagement face ( 32 , 106 ) and spaced from the external peripheral surface ( 30 , 118 ).