The sharpened edge 148 performs the major portion of {HEAD ~ the cutting} during a cutting operation and is periodically sharpened by {TAIL ~ the sharpening mechanism} 78 
The sharpened edge 148 performs the major portion of { HEAD ~ the cutting } during a cutting operation and is periodically sharpened by { TAIL ~ the sharpening mechanism } 78
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH