Such apparatus may be used to machine internal and external surfaces of a polygonal or other non circular contour, and is especially suitable for the machining dies used in the casting of hexagonal bolt heads, more particularly domed bolt heads wherein a hexagonal rim merges into {HEAD ~ the domed surface} of {TAIL ~ the head} 
Such apparatus may be used to machine internal and external surfaces of a polygonal or other non circular contour , and is especially suitable for the machining dies used in the casting of hexagonal bolt heads , more particularly domed bolt heads wherein a hexagonal rim merges into { HEAD ~ the domed surface } of { TAIL ~ the head }
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 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 REL TAIL TAIL TAIL TAIL TAIL TAIL