An end conical portion is formed at {TAIL ~ the apex} of said {HEAD ~ intermediate conical portion} and axially aligned therewith, with the intermediate conical portion having a cone half angle greater than the end conical portion 
An end conical portion is formed at { TAIL ~ the apex } of said { HEAD ~ intermediate conical portion } and axially aligned therewith , with the intermediate conical portion having a cone half angle greater than the end conical portion
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL 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 OTH OTH