In-House Calibration Requirements - Use of Grade 2 set of gage blocks

[jkittle]

I have a question regarding calibrations being done in-house.

I recently visited a supplier who has had some issues and these issues led me to measurement instruments. When I started looking at the tools I questioned the calibrations as i found several instruments past there next due date.

Anyway I started looking at the calibration data, master gage blocks being used, and calibration work instructions.

The issues I found:

1. Gage blocks were a grade 2 and not certified or calibrated, no documents
2. Calibration work instructions were very vague and had little detail and were hand written in a binder. Example for 6” calipers was use gage block set ABC and check at 1”, 2” 3” etc.

My questions are:

1. Can a grade 2 set of gage blocks be used to calibrate other tools (assuming that they were certified themselves)
2. Are there any guide lines a calibration work instruction should follow? These were the most un-detailed instructions I had ever seen for hand measurement tools

Thanks,

Jerry

 

[AndyN]

Re: In-House Calibration Requirements

Jerry:
The grade 2 can be used - it depends on the accuracy they want to achieve with the measuring device.

Calibration details only need to be as detailed as the competency of the person doing the cal. However, the technical detail, - spindle flatness, etc may not be sufficient for a valid cal.

 

[Hershal]

Andy is correct, Grade 2 can be used. If you can get your hands on at USN NA 17-20 series or USAF T.O. 33K series, then they are great patterns for procedures.