In either case, the head of the fastener may have a tapered forward surface portion for engagement with the walls of {TAIL ~ an access bore} in an object to be fastened to {HEAD ~ the workpiece} 
In either case , the head of the fastener may have a tapered forward surface portion for engagement with the walls of { TAIL ~ an access bore } in an object to be fastened to { HEAD ~ the workpiece }
OTH OTH OTH 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 HEAD HEAD HEAD HEAD HEAD HEAD