Cutting insert 6 including a groove formed in {HEAD ~ the upper surface} and extending in {TAIL ~ an axial direction} 
Cutting insert 6 including a groove formed in { HEAD ~ the upper surface } and extending in { TAIL ~ an axial direction }
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL