Compare measured deviation between metal faces or edges with a specified parallelism tolerance and calculate pass/fail, remaining tolerance and tolerance utilization.
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Parallelism is a geometric relationship describing how closely a surface, line or feature maintains a parallel orientation to a specified datum or reference feature.
For metal components, parallelism requirements may apply to opposing faces, edges, surfaces, axes or other features. The applicable drawing defines the required datum relationship and tolerance zone.
This calculator performs a straightforward numerical comparison between the measured maximum parallelism deviation and the specified maximum tolerance.
If the measured deviation exceeds the specified limit, the numerical check is shown as FAIL.
Remaining tolerance shows how much numerical allowance remains between the measured deviation and the specified maximum.
A positive value indicates tolerance remains. Zero means the measurement is exactly at the specified limit. A negative value means the limit has been exceeded.
Tolerance utilization expresses the measured deviation as a percentage of the specified parallelism limit.
For example, a measured deviation of 0.05 mm against a 0.10 mm tolerance uses 50% of the specified numerical allowance.
When two metal faces are required to be parallel, the measured relationship is evaluated against the specified datum or reference condition. The actual inspection method depends on the drawing and applicable geometric tolerancing requirements.
The numerical comparison in this tool assumes that the entered measurement already represents the relevant maximum parallelism deviation.
Parallelism can also apply to edges or other linear features. The applicable drawing determines the feature being controlled, datum reference and tolerance zone.
This calculator does not determine the datum structure or tolerance-zone construction. It simply checks the entered measured deviation against the entered limit.
Parallelism and flatness are different geometric controls. Flatness controls a surface relative to an ideal plane without requiring a datum. Parallelism controls the orientation of a feature relative to a datum or reference.
A face can have acceptable flatness while still having a parallelism problem relative to another face or datum.
Parallelism controls an orientation that should remain parallel to a datum or reference. Perpendicularity controls an orientation at approximately 90 degrees to a datum or reference.
They are separate geometric characteristics and should be checked against their respective drawing requirements.
This calculator performs a numerical comparison only. It does not establish the correct datum reference, tolerance zone, inspection method or governing geometric-tolerancing standard.
Actual acceptance should be based on the applicable engineering drawing, product specification, inspection plan and calibrated measurement equipment.
When does the parallelism check pass? The numerical check passes when measured deviation is less than or equal to the specified parallelism limit.
What is remaining tolerance? It is the specified maximum parallelism tolerance minus the measured deviation.
What does 100% utilization mean? The measured deviation is exactly equal to the specified tolerance limit.
What happens above 100% utilization? The measured deviation exceeds the specified tolerance and the numerical result becomes FAIL.
Can I check parallel faces? Yes. Enter the measured maximum deviation between the relevant faces and the applicable specified limit.
Is parallelism the same as flatness? No. Parallelism controls orientation relative to a datum or reference, while flatness controls a surface relative to an ideal plane.
Does PASS certify the component? No. It only confirms that the entered numerical measurement satisfies the entered limit.