{HEAD ~ Key way} 4 opens to its front end at {TAIL ~ front face} 6 of housing 2 and is blind or closed at opposite end 7 of housing 2 
opens at
{ HEAD ~ Key way } 4 opens to its front end at { TAIL ~ front face } 6 of housing 2 and is blind or closed at opposite end 7 of housing 2
HEAD HEAD HEAD HEAD HEAD HEAD OTH REL OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH