Transcription: True position tolerancing produces an allowable error which is independent of direction. Notice that the shape outlined by the center of the hole is a circle, whose perimeter points are equidistant from the center. The circle circumscribes the square and is 57% larger than the square on the previous page. This technique maximizes the allowable error within a given tolerance and still allows the mating parts to fit. The increased tolerance facilitates manufacturing and reduces costs.
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