In the case of a nail, the plug of {HEAD ~ filler material} would be joined to {TAIL ~ the nail head} 
In the case of a nail , the plug of { HEAD ~ filler material } would be joined to { TAIL ~ the nail head }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL