Posting Measuring Equipment Accuracy for User Information

[greif]

I like the idea that each machine should have its measuring capability posted so all users know if it is appropriate to anything that is to be measured. Others think that the person writing up a work instruction needs to know this and specify an instrument for those doing the work.

What are common practices used elsewhere?

 

[Ninja]

FWIW, I have always seen (and done) this by specifying the equipment to be used.
Posting capability for each piece of equipment and letting users make their own choices seems much higher risk.

Heck, it is hard enough to get folks to stop using equipment out of calibration life...I would think it would get much worse if everyone could decide for themselves if a gage was accurate enough for what they wanted to do.

 

[Michael_M]

We have a 1/3 page (part of a larger 1 page inspection requirements work instructions) that define the instrument to use based on the tolerance of the measurement to be taken. For example, if the tolerance is ±.010", you can measure with dial or digital calipers or any device rated as 'better' (micrometer for example). If the dimensional tolerance is ±.001", a micrometer is required, either digital or spindle read, however, a tolerance that is ±.0005 requires a digital micrometer only, you cannot use a spindle read.

These are generic instructions that can be, and sometimes are, overridden by specific traveler/routing instructions. We do not want to tell people to use a pair of calipers to measure a specific dimension if they want to use a micrometer to measure but we do not want people using calipers to measure when a micrometer is required.

 

[Jim Wynne]

I like the idea that each machine should have its measuring capability posted so all users know if it is appropriate to anything that is to be measured. Others think that the person writing up a work instruction needs to know this and specify an instrument for those doing the work.

What are common practices used elsewhere?

What certification standard are you working with? This is one reason that MSA is done using actual parts rather than something generic such as gage blocks. The required should be predetermined, and if you want to allow for different types being used (caliper vs. micrometer, e.g.) the different gages should be qualified independently.

 

[Mikey324]

We have specific measuring equipment called out for each job. This way we don't end up with an inspector using a tape measure to check a +/- 0.00005" tolerance.