Regarding the decision to return your gauges back to the manufacturer for calibration of do it yourself. It all depends on what equipment you have now and what skills you have available. If you have the equipment and skill set in your team, then I sure you can calibrate the critical gauges in house (provided you have the time). If not you are looking at purchasing a suitable calibration equipment, delivery times, training . . . .
I had a QC department that held 2500 (sets) of both plug and ring gauges and decided that sending them out for calibration was the simplest option, I could have done it in-house but I thought with the amount we had, we could meet ourselves coming back, if you know what I mean. Also, I would never send it back to the manufacturer they are always more expensive then calibration houses.
This yearly calibration thing that people keep mentioning, gets my back up does that, you calibrate as and when required and not to any scheduled timeframes. I had a new production manager that once came down and asked why some of the gauges were calibrated every 7 years, and insisted I changed it because we would pass ISO audits. I passed him the ISO manual and asked him to highlight for where it stated I had to calibrate my gauges at set timeframes, obviously he couldn’t.
Another thing, all it states is to ensure the method of measuring is suitable for the job at hand. To me that means initial gauge studies (via the MSA principle) and conduct health checks should it need it.
Regards
Lee01