Check Standard Stability Log Worksheet
Between calibrations, a check standard or master piece tells you whether the gage still behaves. This worksheet logs each check, computes deviation and percent of allowed deviation per row, and summarises bias and spread.
| Date | Gage ID | Checked by | Assigned value (mm) | Reading (mm) | Allowed deviation (mm) | Deviation | Percent of allowed | Action | |
|---|---|---|---|---|---|---|---|---|---|
0.001 | 25% | ||||||||
0.001 | 25% | ||||||||
0.002 | 50% | ||||||||
0.003 | 75% | ||||||||
0.003 | 75% | ||||||||
0.005 | 125% |
Overwrite the example rows with your own checks. Allowed deviation is the action limit you set from the gage's accuracy requirement, often a fraction of the part tolerance. A steady climb in deviation, as in the example, is the signal to investigate before the next calibration is due.
Automate gage check alerts
Optional: discuss triggering holds or tasks in your ERP when a check standard reading passes a limit.
Optional. The tool and every export work without this. No spam.
How to use it
Add a row each time you measure the check standard. Enter the date, the gage ID, the person, the assigned value from the standard's certificate, the reading and the allowed deviation. Deviation and percent of allowed are calculated for you, and totals show the average deviation, the worst case and the count. Export to Excel to chart the deviations or attach the log to the gage record.
- Check at a fixed frequency, such as weekly or start of shift.
- Use the same standard and method every time.
- Write an action in the row whenever deviation passes a warning level.
Why check standards matter
Calibration shows the gage at a point in time. A check standard shows it in between, so you catch damage, wear or contamination before it affects many parts. ISO 10012 and ISO/IEC 17025 both expect monitoring of the validity of results, and intermediate checks are a standard way to do that. The log also gives you drift data that feeds interval decisions.
Reading the log
Random scatter within the allowed band suggests a stable gage. A steady trend, like the rising deviation in the example, suggests wear or a creeping fault. A sudden step suggests a knock or contamination. A mean bias that sits away from zero but stays steady suggests the gage reads consistently off, which may be corrected or documented. Percent of allowed above 100 means stop using the gage and review parts measured since the last good check.
Common mistakes
Do not adjust the gage to the check standard each time, that hides the drift you want to see. Do not use a production part as the standard unless its value was assigned by a calibrated reference. Avoid logging only passes, the log is useful because of its trend. Finally, ensure the standard itself is calibrated and stored well, otherwise you are tracking the standard, not the gage.
Frequently Asked Questions
How often should I check?
Frequency depends on use and risk. High-use, tight-tolerance gages are often checked daily or per shift, others weekly or monthly. Start frequent, then relax based on stability evidence.
What should the allowed deviation be?
Base it on the accuracy needed for the measurement, often a fraction of the tolerance, or the gage's permissible error. Document the basis in your procedure.
What do I do on a failed check?
Stop use, tag the gage, retest, and if confirmed review measurements made since the last good check. The impact assessment template helps document this.
Can I use this for a ring or plug gage?
Yes, enter the reference value of the master and the reading in the units you use. For attribute gages the log is less useful, record go or no go checks instead.
If your gage checks are on paper, we can help move them into your ERP or quality system with triggers for out-of-limit readings.
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