Hi, I have a great confusion existing between posititional tolerance, concentricity and run out. When I read the definitions in ASME Y14.5 M, I feel them mathematical. Can somebody pl. explain me their significance in function? Say, I have a primary axis "Datum A" and there is another cylinder in series to that. What will happen to this cylinder, when I give a positional tolerance or concentricity or run out? When to use what among these? http://imgur.com/uTNJJWw Thanks.