However, the apparatus is adapted to provide for machining a surface profile which varies in the axial direction, for example a surface having {HEAD ~ a hexagonal profile} which merges into {TAIL ~ a circular profile} 
merges into
However , the apparatus is adapted to provide for machining a surface profile which varies in the axial direction , for example a surface having { HEAD ~ a hexagonal profile } which merges into { TAIL ~ a circular profile }
OTH OTH OTH 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 HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL