Position tolerance
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Position Tolerance is a Geometric Dimensioning and Tolerancing (GD&T) location control used on engineering drawings to specify desired location as well as allowed non-conformitied to the position of a feature on a part. Position tolerance must only be applied to features of size, which necessitates that the feature have at least two opposible points.
When measured, usually the X & Y measurements are given. In order to convert from X & Y to position tolerance you use the following equation:
Position = 2 x sqrt( (Xvar)^2 + (Yvar)^2 )
where Xvar & Yvar are the difference between their actual measurements and the basic dimension which controls them.
This is related to converting rectangular coordinates to polar coordinates with a factor of 2 included as it is needed to convert the radius to a diameter.
