How are you calibrating depth mics or any equipment that has interchangeable rods? For the last 12 years our have been calibrated and stickered as "calibrate at use" because of the rods being interchanged. We are getting a minor non-conformance from a customer because we do not have records of "calibrate at use". Is everyone else just calibrating the tools and assuming when the rods are interchanged they are correct? What are other people doing for this situation?
Depth Mic Calibration
- Thread starter Jrupnow
- Start date
Ron Rompen
Trusted Information Resource
calibrate the micrometer head to validate the wear (or lack of wear) on the screw thread. Measure/calibrate each rod with a height gauge (start by measuring the initial value when received, and compare to that0.
UncleFester
Involved In Discussions
It looks like you're verifying rather than calibrating, as you're not measuring squareness of the datum face to the axis of the rod, not flatness of the datum face as would be expected on a certificate of calibration. What tolerances are you using per rod length at verification? As a simple guide, you could have a series of tolerances per rod length and check this when changing each rod. You could get the table from BS 6468.
The following is our instructions on depth micrometers:
- Micrometer, Depth
- ±.0005” from gage actual measurement. These gage typically only read to .XX1. Tolerance on measurement is ½ distance between lines.
- The range of the device will be measured, as applicable:
- Using a single rod, measure minimum to maximum 4 points. At least one measurement to be at a non-standard increment (i.e., measuring .0625)
- Measure 1 point for each additional rod in set.
- Inspect each rod for bend and/or damage.
ChrisM
Quite Involved in Discussions
How? Visual inspection, or do you have a special machine to measure bending and potential damage?
qualitystartup
Involved In Discussions
We used to do a visual check by rolling them on a surface plate.
It's visual and checking flatness against a flat surface, but it only visual.
