Patent ID: 8747031

Claim:
A cutting insert ( 40 , 140 , 340 ) comprising: a first surface ( 62 , 162 , 362 ), a second surface ( 64 , 164 , 364 ) and a peripheral surface ( 66 , 166 , 366 ) extending therebetween, the first and second surfaces ( 62 , 162 , 362 , 64 , 164 , 364 ) meeting the peripheral surface ( 66 , 166 , 366 ) at first and second peripheral edges ( 42 , 142 , 342 , 44 , 144 , 344 ), respectively, at least a portion of at least one of the first and second peripheral edges ( 42 , 142 , 342 , 44 , 144 , 344 ) forming a cutting edge ( 46 , 146 , 346 ), and a cutting insert bore ( 60 , 160 , 360 ) extending between the first and second surfaces and having a bore axis B, the cutting insert bore comprising: a first bore portion ( 68 , 168 , 368 ) opening out to the first surface ( 62 , 162 , 362 ), a second bore portion ( 70 , 170 , 370 ) opening out to the second surface ( 64 , 164 , 364 ), and a third bore portion ( 72 , 172 , 372 ) located between and merging with the first and second bore portions, the third bore portion ( 72 , 172 , 372 ) having a cross-section in a bore plane P which is perpendicular to the bore axis B and spaced from the first and second surfaces, wherein: the third bore portion has a major centerline M perpendicular to the bore axis B and a minor centerline N perpendicular to the bore axis B defining, respectively, major and minor dimensions D M , D N of the cross section of the third bore portion ( 72 , 172 , 372 ), and the cross-section has an oval shape.