When it is desired to fluidly connect {HEAD ~ stem bore} 454 with the passages within {TAIL ~ valve body} 15, nut 23 is rotated and unthreaded away from valve body 15 
When it is desired to fluidly connect { HEAD ~ stem bore } 454 with the passages within { TAIL ~ valve body } 15 , nut 23 is rotated and unthreaded away from valve body 15
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH