A brace may be provided to keep {HEAD ~ post hole digger assembly} from rocking on {TAIL ~ the movable support bar} 
from rocking on
A brace may be provided to keep { HEAD ~ post hole digger assembly } from rocking on { TAIL ~ the movable support bar }
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL