Formula for calculating ovality of a circular hole

[Kishan Majethia]

Can anybody guide me what basically is the formula for finding ovality for a circular hole of given dimension and tolerance? I think it would be (Upper tolerance limit + Lower tolerance limit)/2. But not able to find any reference for the same.

Please also give reference for the same if possible.

Thanks in advance for any help.

 

[Simon Bridge]

http://en.wikipedia.org/wiki/Ovality
... you can relate that to the definitions of "dimension" and "tolerance" that you are using.

 

[Ranger Mike]

i suggest you look into ANSI B 89.3.1 standard on measurement of out of roundness. Basic definition is maximum radius - minimum radius = out of round condition.
You ca n not define a inside diameter or outside diameter with any type of diametric check ( caliper or micrometer measurement or use of v-block and dial indicator.
tolerancing is a whole other matter so refer to ANSI Y 14.5 standard on Geometric and Dimensional Toleranceing