{HEAD ~ Each end surface} includes an upper portion connected to the cutting edge, and {TAIL ~ a lower portion} connected to the upper portion by a concave transition portion 
{ HEAD ~ Each end surface } includes an upper portion connected to the cutting edge , and { TAIL ~ a lower portion } connected to the upper portion by a concave transition portion
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH