{HEAD ~ An apparatus} for machining a workpiece to a predetermined contour in accordance with {TAIL ~ a reference pattern} comprises a cam mechanism which defines the reference pattern 
{ HEAD ~ An apparatus } for machining a workpiece to a predetermined contour in accordance with { TAIL ~ a reference pattern } comprises a cam mechanism which defines the reference pattern
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH