A message is output when the degree of the wear position deviates from {HEAD ~ the degree} of {TAIL ~ the reference position} by more than the degree of wear permissible 
of
A message is output when the degree of the wear position deviates from { HEAD ~ the degree } of { TAIL ~ the reference position } by more than the degree of wear permissible
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH