{TAIL ~ An apparatus} for checking the diameter of {HEAD ~ a cylindrical part} in orbital motion about a geometrical axis in a numerical control grinding machine, said apparatus comprising: 
{ TAIL ~ An apparatus } for checking the diameter of { HEAD ~ a cylindrical part } in orbital motion about a geometrical axis in a numerical control grinding machine , said apparatus comprising :
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH