Also, it is to be noted that trailing surface 25 on each tooth need not be rectilinear; it may have {HEAD ~ a variety} of contours as provided by the shape of {TAIL ~ grinding wheel} 12 
Also , it is to be noted that trailing surface 25 on each tooth need not be rectilinear ; it may have { HEAD ~ a variety } of contours as provided by the shape of { TAIL ~ grinding wheel } 12
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 OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH