{HEAD ~ A precision machining system} for machining a workpiece into {TAIL ~ a desired surface} with two tool driving units 
{ HEAD ~ A precision machining system } for machining a workpiece into { TAIL ~ a desired surface } with two tool driving units
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH