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Geometric Tolerance for a Shaft expressed with a M modifier

Where M or L modifiers are assigned to a Geometric Tolerance, the variation is caused by the following tolerances:

  • The Tolerance of Size
  • The Geometric Tolerance
  • Bonus Tolerance that accrues when the Feature size goes away from the Critical Limit of Size.
Bonus Tolerance is a useful concept that makes manufacturing processes less expensive. DVA needs to take correct cognizance of the 3 tolerances above to evaluate the Feature envelopes and consequently the gap. The animation shows a case of gap variation, when the Geometric tolerance is expressed with a M modifier.