One side of that material is V shaped to extend into and conform to the V shape of said race sufficiently along {HEAD ~ the length} of the race for centering {TAIL ~ one plate} 
One side of that material is V shaped to extend into and conform to the V shape of said race sufficiently along { HEAD ~ the length } of the race for centering { TAIL ~ one plate }
OTH OTH 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 OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL