Each of the first and second end surfaces includes {HEAD ~ an upper portion} connected to a respective one of the first and second cutting edges, and a lower portion connected to {TAIL ~ the upper portion} by a concave transition portion, wherein the lower portion is recessed axially inwardly relative to the upper portion 
Each of the first and second end surfaces includes { HEAD ~ an upper portion } connected to a respective one of the first and second cutting edges , and a lower portion connected to { TAIL ~ the upper portion } by a concave transition portion , wherein the lower portion is recessed axially inwardly relative to the upper portion
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH