Thus, {HEAD ~ any required adjustment} may be obtained by positioning {TAIL ~ the appropriate slot} on the key of the shaft 
obtained by positioning
Thus , { HEAD ~ any required adjustment } may be obtained by positioning { TAIL ~ the appropriate slot } on the key of the shaft
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH