What is the best way to handle pin gages? I have considered sending them out for calibration, but my manager has stated we can write a procedure "Calibrate before use" does anyone have such a procedure I can look at?

Thanks

"Calibrate Before Use" (CBU) in my experience is not a calibration method; it indicates the item must be calibrated before you use it. This could include items you send out to a vendor or what ever method applies.

The application of CBU would be if you are not going to use them for some period of time. You then could label them CBU, and calibrate them when you need to use them. This is a cost saver in terms of either manhours or vendor charges, but does not substitute for normal calibration.

As I am not a dimensional expert, I don't immediately recall the normal method (whether it be a high accuracy super-micrometer, or other dimensional measurement.

I have my pin gages marked “Calibrate Before Use”. My procedure requires the pin be checked with a micrometer before use. This method works well for us. We have a large set and many of the pins are never used. At the other extreme, some are used daily and subject to wear. Not only does it save the cost of a yearly calibration of the set, it precludes the use of worn pins.

If it will work for you, go for it.

And some are put back in the wrong hole in your gage pin drawer. It happens all the time. I like the idea of a sign saying to calibrate before using.

I have my pin gages marked “Calibrate Before Use”. My procedure requires the pin be checked with a micrometer before use. This method works well for us. We have a large set and many of the pins are never used. At the other extreme, some are used daily and subject to wear. Not only does it save the cost of a yearly calibration of the set, it precludes the use of worn pins.

If it will work for you, go for it.
I agree we only use about 10 pins out of the set. What is the best way to do this an procedure or work instruction?
:thanx:

You could have such a procedure and it would work well, depending on how the calibration is done.

You would need to send the pin(s) to a cal lab that includes pins and/or gage blocks in their scope. If they have been accredited by a recognized AB (e.g. IAS, A2LA, NVLAP, L-A-B), then the equipment, traceability, and technical proficiency of the personnel have all been assessed. That means they have a super-mic, controlled environment (20 C +/- 1 C), and are proficient at that specific measurement, and can provide the mesurement uncertainty so you know just what your actual measurements entail.

Yes, it is more expensive to use such a cal house and have the accredited cal.

Hope this helps.

Hershal

I agree we only use about 10 pins out of the set. What is the best way to do this an procedure or work instruction?


My work instruction is a laminated sign that says "CALIBRATE BEFORE EACH USE". Of course it has a date and my approval on it!

Our company literally has thousands of plug gages. We use the calibrate before use process. It has passed 3 years of audits. It's not even written procedure technically. It is simply a gage calibration / sign out sheet. The operator records who he/she is, what machine it is being used at (traceability), what the target dimension is (i.e. 1.0000"), what the actual dimension is (i.e. 1.0001"). We then have a column on the sign out sheet that specifies that the plug gage must be +/- 0.0002" of the target dimension in order to be used. If it is out of dimension, it is taken out of service. We use NIST traceable Mitutoyo micrometers that measure to 0.00005" for proper accuracy. The operators check the gage in three places (on both ends if it doesn't have a handle). This method has greatly reduced individuals from using the incorrect gage accidently. It also has helped us from shutting down a press when a gage may have a nick or ding on it that throws it out of tolerance. Lastly, it greatly reduced the QC time in having to calibrate every gage every 6 months or a year. The sign out sheet becomes your record of calibration. FYI...our gages are stored in a climate controlled environment so the ISO requirements for temp., humidity, cleanliness etc. are met as well. It should be said that our tolerances on our parts are no tighter than .003" total range. This procedure may not work properly if you have to hold .001" total tolerance.

We are a machining shop with a small production environment and gauge pins are used all the time. I have "Mic Before Use" and "For Reference Only" labels on our gauge pin sets which seems to work fine.
As for yearly calibration; we do a visual check for missing and worn pins and replace them as necessary.
The pins are used on various jobs where bore sizes are anywhere from .061" to 1.000" and tolerances are generally .003". We do have bore gauges starting at around .360 and up so if someone has a tight tolerance of .0005" or less we give them a bore gauge.
It is not feasible to calibrate every pin every time it is used. I'd be babysitting pins and nothing else if I HAD to do that.
gaugefixer

We have a few highly used pins that I put cal stickers on and calibrate on a fixed interval (i.e. every 60 days). Others, like entire sets, have an "uncalibrated - for reference only" or "calibrate with each use" sticker.

Calibration is done in-house with a written WI that specifies the use of .0001" accuracy calibrated mics and states how close the actual reading must be to the specified pin size for it to be used.

We also specify what the pin tolerance must be based on the hole size being tested and its spec. tolerance.

We caibrate all pin gage sets on a yearly cycle and have stickers on all that say verify with each use to make sure the right pin is in the slot. Our work instruction states we need at least a 4 to 1 ratio so depending on the class dictates what type of instrument we need to use for calibration.

We calibrate almost all of our pin gages. We have the cheap set that usually start at .011 to .060 like the Vermont in a metal box, and these are labeled "check with std prior to use". The std being a Mitutoyo Digimatic Thickness Gage or a Digimatic Micrometer. For our Deltronic pin gages here in the calibration lab, we calibrate those in house using our Z-Mike Gold series laser, but we apply a "use label" to each pin since they are in a set. In order to use the pin, the user must first remove the "use label". When the pins become due, it's quite easy to see which pins have been used, and we calibrate only those that were used.

To speed up the recording of data when calibrating pin gages, we have the output of the laser mic sent into an Excel worksheet that prints out a worksheet for us.

Hi,

I know this is an old thread, but it's applicable to my question. We are an small printer company that assembles purchased parts (sheet metal, plastic, electronics) to make our product.

My question is regarding gages used for incoming inspection. We use:

- calipers
- pin gages
- feeler gages (occasionally)
- granite surface plate (occasionally)

I don't think I can call these gages "reference only" even though I'm only doing incoming inspection, but what if I do this:

- Send out the calipers for annual calibration to an accredited lab.
- Perform an internal "calibration" on the pin gages with my calibrated calipers.
- Mark the feeler gages and granite plate "reference only".


Any problems with this plan?

Thanks,
Emily

Not knowing what you use the granite plate for or the feeler gages, I can't really tell you in confidence that you can use them for reference only. I calibrate all of my surface plates except two. The only reason they are marked for reference only because they are being used as tables. (This I don't like but I can't take them away)

Feeler Gages: If you are using them to check your incoming product then you need to calibrate them based on the tolerance you are checking, remember the 10:1 rule, or check them to manufacturer recommendations. The only way you wouldn't have to calibrate them would be if you were using them to set a machine or device that DID NOT in anyway reflect on the dimensions of the product.

Calipers: Yes sending them out yearly would be fine. Exception would be if the calibration lab starts to document a need for them to be calibrated on a more frequent basis.

Pin Gages: Sorry but I have not seen ANY calipers that would have the ability to calibrate a pin gage (10:1 rule again) even if you check them to a fixed limit gage tolerance you are still looking at .005mm on the sizes between .74mm-20.96mm.

Hopefully this will help some. Others may have more detail for you, but I wanted to give you a quick answer anyways.

Thanks
Dale

Thanks Dale. I'm starting to think that I should just suck it up and send everything out for calibration. It's the safest bet.

I appreciate your quick response.


Emily