When the nut is rotated in a first direction, the nut shoulder contacts the stem annular flange, urging {HEAD ~ the stem} axially towards {TAIL ~ the valve body} 
axially towards
When the nut is rotated in a first direction , the nut shoulder contacts the stem annular flange , urging { HEAD ~ the stem } axially towards { TAIL ~ the valve body }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL