Do not round a borderline result into conformity without the agreed reporting and decision rule. Preserve the original reading, check the method’s suitability and ask the quality authority how uncertainty is handled for this requirement. A displayed number and an acceptance decision are related, but they are not the same record.
Check method suitability, uncertainty and the agreed decision rule
Confirm the feature, datum, units and exact tolerance limits on the controlling drawing. Retrieve the inspection plan’s decision rule and reporting convention. Check whether the apparent closeness comes from a conversion or a display-format change rather than the original measurement.
Record the raw result as obtained, together with instrument and method references. Do not add implied precision beyond what the method supports. The tolerance-control guide provides the broader framework; the immediate question is how this particular near-limit observation should be interpreted under the approved acceptance approach.
Avoid rounding a borderline reading into automatic conformity
Ask a qualified reviewer to assess measurement uncertainty and other relevant method limitations. Resolution, calibration status and setup can be relevant, but a buyer should not derive an improvised uncertainty allowance from the last digit on the display. Use the measurement system’s documented basis.
Check whether the agreed rule already explains how near-limit results are decided. If it does, apply that rule consistently rather than creating a stricter or looser one for the current supplier. If it does not, obtain an authorized clarification and address any contractual implications before changing the acceptance basis.
A repeat measurement may help investigate a questionable setup, but repeating until a passing value appears is not a defensible method. If repeat work is authorized, define its purpose, preserve all observations and document any correction to the original method. Do not average results casually or discard inconvenient readings.
Escalate or remeasure under the quality plan while preserving the raw result
Have the authorized reviewer record the result, the rule applied and the disposition. If the evidence cannot support a decision, hold the affected characteristic and identify the next step, such as a more suitable measurement or technical review. Avoid presenting an unresolved near-limit result as a confirmed defect or confirmed pass.
For the carbide blade drawing, carry the clarified reporting convention and decision rule into future inspection instructions. Keep units and conversions consistent so a spreadsheet or certificate template does not silently change the outcome. A rounded presentation may be useful for communication, but its relationship to the original data must remain clear.
Close the case with an explanation that another reviewer can reproduce from the record. The goal is consistent treatment of uncertainty and limits, not a universal numerical margin or a preference for whichever rounding convention releases the shipment fastest.
NIST connects fitness for purpose with measurement uncertainty. NIST Metrological Traceability: FAQ and Policy ↗
