A helical insert or {HEAD ~ key lock insert} may be utilized as {TAIL ~ the inserts} 82 
utilized as
A helical insert or { HEAD ~ key lock insert } may be utilized as { TAIL ~ the inserts } 82
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH