In the arrangement of FIG 8 it may be desirable to provide increased relief behind {HEAD ~ each primary cutter} 21 to reduce {TAIL ~ the area} of wear flat which develops behind the cutting edge as the cutter wears down 
to reduce
In the arrangement of FIG 8 it may be desirable to provide increased relief behind { HEAD ~ each primary cutter } 21 to reduce { TAIL ~ the area } of wear flat which develops behind the cutting edge as the cutter wears down
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH