The gauge also has a pair of rest bars mounted on the base plate to support the brake block at {HEAD ~ the specified radius} at {TAIL ~ first and second measuring points} 
The gauge also has a pair of rest bars mounted on the base plate to support the brake block at { HEAD ~ the specified radius } at { TAIL ~ first and second measuring points }
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 HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL