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