Hello All, I was just recently appointed with a project of organizing, redesigning, implementing and maintaining a calibration system for our gages and measurement tools we use here at our machine shops. So far ive got everything up to date except one section im struggling with. I want to try and save us some money by calibrating some tools in house like our plug gages, block/pin gages etc that dont need adjustment that often or any at all. Ive got stickers to put on gages for cal validation, ive got logs for when validating or calibrating. My only issue is finding the correct methods in doin the c hecks. I need to know how to calibrate a gage block, a pin, a plug gage so on so forth. If anyone could help me with this, that would be great!!
First Time Managing Calibration and Measurement System. Need Help.
- Thread starter RCasey88
- Start date
Casana
Blueberry Nut
Hi, I’m not familiar with the calibration for plug gages, etc. but perhaps what we do with some other items may help you. Here’s some examples:
- We use calibrated timers when doing one of our process. Rather than ‘calibrate’ the timers, we just purchase new ones (much cheaper!)
- For our thermometers, we’ll keep a certified thermometer (that is sent out for calibration) then use it to verify the readings of our other thermometers in the same set of fluids, per a set schedule. The certified thermometer is shipped out for calibration so that’s only one item calibrated instead of dozens.
Hello, In doing calibration of thread plugs, you will need a couple items which may cost a pretty penny, depending on your tolerances. Also just a reminder your equipment should be 10x better resolution than what you are calibrating. But what you need is a linear measuring device, thread wires and grade 0 or 00 gage blocks. You can use a .00005 resolution micrometer instead of linear measuring device. The advantage to having the linear device is you can also do gage blocks, pin gages, plug gages, indicators of many types, solid rings and some other assorted gages if you pick the one that best suits your needs.
There are multiple sources that you can Google for basic calibration procedures.
Here is a source for the items you have mentioned: Calibration Guidelines
Plug gauges and gauge blocks can be really tricky to calibrate, depending on their grade.
The tools are expensive, they demand environmental controls or a lot of math to compensate for the lack of environmental controls.
They also require a lot of "technique" to get the readings right, and those techniques come with experience.
Here is a source for the items you have mentioned: Calibration Guidelines
Plug gauges and gauge blocks can be really tricky to calibrate, depending on their grade.
The tools are expensive, they demand environmental controls or a lot of math to compensate for the lack of environmental controls.
They also require a lot of "technique" to get the readings right, and those techniques come with experience.
Verifying plug gauges, gauge blocks and pin gauges in house will likely cost you more in equipment than you will save by doing it in-house and then you'd need to have that equipment and standards periodically certified to national standards by an outside service.
Your time alone to verify a set of pin gauges one by one would probably cost more than sending them out, or just buying a new set every two years.
Your time alone to verify a set of pin gauges one by one would probably cost more than sending them out, or just buying a new set every two years.
May I toss in a gentle reminder from the world of calibration.
If you replace any calibrated tool without a final calibration then you have lost measurement traceability.
Suppose your tool went out of tolerance after its previous calibration. If you do not perform a final calibration on it you will never know you were using an out of tolerance tool, or the risk or impact that involves.
Having a valid calibration label on a tool means it was found in tolerance at the time it was calibrated. That does not guarantee that it will remain in tolerance.
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Ron Rompen
Trusted Information Resource
Scott K, I disagree with your statement regarding in-house calibration of pin gauges, gauge blocks, etc.
One of the determining factors for inhouse or external calibration is the accuracy that is required. For example, I calibration my gauge pins to ± 0.0005", using a bench micrometer (3rd party calibrated), which is calibrated to 0.0001". For MY purposes, this is sufficiently accurate.
For my gauge blocks, I calibrate them using our CMM (3rd party calibrated), which is calibrated to .00005". Again, this is sufficiently accurate for my purposes.
The cost of getting a set of blocks done is around $800 (81 pc Grade B) which is excessive.
The main thing that I always keep in mind when setting up a calibration program is that it is set up to suit MY processes (unless the customer has a specific requirement), not to meet anything else.
One of the determining factors for inhouse or external calibration is the accuracy that is required. For example, I calibration my gauge pins to ± 0.0005", using a bench micrometer (3rd party calibrated), which is calibrated to 0.0001". For MY purposes, this is sufficiently accurate.
For my gauge blocks, I calibrate them using our CMM (3rd party calibrated), which is calibrated to .00005". Again, this is sufficiently accurate for my purposes.
The cost of getting a set of blocks done is around $800 (81 pc Grade B) which is excessive.
The main thing that I always keep in mind when setting up a calibration program is that it is set up to suit MY processes (unless the customer has a specific requirement), not to meet anything else.
Sure. We checked pin gauges before each use with a in-calibration micrometer. Then just replaced them all every two year whether there were problems or not. The old ones went to the machine shop as "Reference only". We had full sets of pin-gauges from .011 to .650, I believe. so it would have been lots of time and work to verify them all with a super mic.
Other tools that could be more easily damaged or knocked out we would get an "as received" and "as returned" report as part of the cert.
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OK
Worked for me in a few machine shops I've managed Quality in, though
Pins - the cost of replacement wasn't a concern to those companies I worked at. I had limited personnel resources to do full verification and it was simply cheaper and more expedient to buy new every couple of years and send the old out to the floor as "reference only".
Blocks - we sent out for recertification.
They preferred to do that vs buy a highly accurate bench mic or a CMM
Enghabashy
Quite Involved in Discussions
1-thread gauges are not applicable to inhouse calibration , it's complex instruments/techniques
2- for more controlling & reducing calibration & verification cost ' we can schedule high grade accuracy references which are maintained as master references gauges & devices in your organization Lab., , it's preferred to be calibrated in competent / accredit Lab. " ISO IEC 17025 " ;
3- according the received calibration certificates & results ' the re-calibration dates should be internally scheduled ; the uncertainty , the reading , how many & conditions of use , --so on--- should be considered when outline the recalibration schedule dates;
4- intermediate checks plan ,the interlab. comparison , verification process should be scheduled also to check the accuracy in between , it's part of validate the results of measuring also;
5-you internal master references could be use for calibrating the 2nd degree of the measuring devices ' i.e. : the block gauges sets could be taken as reference to internal calibrating / verifying the : 1- Depts. Vernier calibers , 2- micrometers , ---& so on , -- this process can reduce the cost also , as well as more controlling the measurement system , --- in advance ' I see that you can take competent course in MSA with manufacturing depts. heads which could be added value for assuring measuring results .
2- for more controlling & reducing calibration & verification cost ' we can schedule high grade accuracy references which are maintained as master references gauges & devices in your organization Lab., , it's preferred to be calibrated in competent / accredit Lab. " ISO IEC 17025 " ;
3- according the received calibration certificates & results ' the re-calibration dates should be internally scheduled ; the uncertainty , the reading , how many & conditions of use , --so on--- should be considered when outline the recalibration schedule dates;
4- intermediate checks plan ,the interlab. comparison , verification process should be scheduled also to check the accuracy in between , it's part of validate the results of measuring also;
5-you internal master references could be use for calibrating the 2nd degree of the measuring devices ' i.e. : the block gauges sets could be taken as reference to internal calibrating / verifying the : 1- Depts. Vernier calibers , 2- micrometers , ---& so on , -- this process can reduce the cost also , as well as more controlling the measurement system , --- in advance ' I see that you can take competent course in MSA with manufacturing depts. heads which could be added value for assuring measuring results .
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