Good Evening All,

I am the Quality Manager for a small manufacturing company in SC. We manufacture gas-liquid separation equipment for industrial applications. We are currently in the process of obtaining our ISO 9001:2000 registration.

I am working on creating all of our forms and SOPs and am currently working on our calibration procedure. We use three different tools for measuring: calipers, micrometers, and tape measures. The calipers and micrometers are used to measure small components. The tape measures are used to verify our individual modules and the overall assemblies against our documentation. I plan on calibrating a set of calipers, micrometers, and tape measures, which will be used to verify our critical dimensions of the product before shipping to our customer. These will be stored in a dedicated cabinet.

What I'm stuck on is must I identify all the other measuring devices used on the production floor during the daily work details. The guys use these during the build process; they are not used for the critical/final dimension checks. I have been told that I must mark these as "FRO" (For Reference Only). What I want to know is must this be done? I've put a statement in the procedure that indicates any tool not identified as calibrated is by default "For Reference Only". Does this statement cover us per ISO 9001:2000 or must we mark each tool as FRO?

Any help with this will be greatly appreciated.

Good Evening All,

I am the Quality Manager for a small manufacturing company in SC. We manufacture gas-liquid separation equipment for industrial applications. We are currently in the process of obtaining our ISO 9001:2000 registration.

I am working on creating all of our forms and SOPs and am currently working on our calibration procedure. We use three different tools for measuring: calipers, micrometers, and tape measures. The calipers and micrometers are used to measure small components. The tape measures are used to verify our individual modules and the overall assemblies against our documentation. I plan on calibrating a set of calipers, micrometers, and tape measures, which will be used to verify our critical dimensions of the product before shipping to our customer. These will be stored in a dedicated cabinet.

What I'm stuck on is must I identify all the other measuring devices used on the production floor during the daily work details. The guys use these during the build process; they are not used for the critical/final dimension checks. I have been told that I must mark these as "FRO" (For Reference Only). What I want to know is must this be done? I've put a statement in the procedure that indicates any tool not identified as calibrated is by default "For Reference Only". Does this statement cover us per ISO 9001:2000 or must we mark each tool as FRO?

Any help with this will be greatly appreciated.


It does not take long to verify a mic or caliper if your tolerances are not extremely tight. You need to calibrate any gage that "matters." If the readings from a gage are going to be used, then you need to know whether they are correct. (The ISO 9001:2000 did away with the narrow definition you are using.) Anything else should be marked "uncalibrated" or whatever. But, it also shouldn't be used for anything you depend on, either.

Helmut, nice post. The suggestion about quick calibration is a good one. It might be worth the time to go ahead and calibrate what you have, than spending a lot of time trying to segregate/ identify/ control, etc. non-calibrated instruments.

Interesting question. I am having a discussion with a couple of my esteemed colleagues on the ASQ discussion board on this subject right now.

Their take: It is not a requirement to mark the gauges "For Reference Only". The system/process should be such that people know to use calibrated instruments for process/production. In other words, it is silly and useless to use such labels.

My take: Ideally, everyone should know to properly inspect instruments prior to use. However, reality states otherwise. If you don't mark an instrument as "For Reference Only", then without super training that non-calibrated instrument will probably end up in the production.

I think both views have merit. My suggestion to you is to develop a system that works for your shop and your culture. Can you adequately separate the instruments where they are not mixed? Is the probability high that people will always use the correct instrument/ gauge/ meter, or is reality they will grab what they can find, so it should be marked clearly?

Whatever you choose, just make sure that non-calibrated instruments will not be used for acceptance readings.

Helmut, nice post. The suggestion about quick calibration is a good one. It might be worth the time to go ahead and calibrate what you have, than spending a lot of time trying to segregate/ identify/ control, etc. non-calibrated instruments.

Interesting question. I am having a discussion with a couple of my esteemed colleagues on the ASQ discussion board on this subject right now.

Their take: It is not a requirement to mark the gauges "For Reference Only". The system/process should be such that people know to use calibrated instruments for process/production. In other words, it is silly and useless to use such labels.

My take: Ideally, everyone should know to properly inspect instruments prior to use. However, reality states otherwise. If you don't mark an instrument as "For Reference Only", then without super training that non-calibrated instrument will probably end up in the production.

I think both views have merit. My suggestion to you is to develop a system that works for your shop and your culture. Can you adequately separate the instruments where they are not mixed? Is the probability high that people will always use the correct instrument/ gauge/ meter, or is reality they will grab what they can find, so it should be marked clearly?

Whatever you choose, just make sure that non-calibrated instruments will not be used for acceptance readings.

I agree. It certainly is not a requirement to mark an instrument as "For Reference Only." Problem is, if you don't people will inevitably use them. Mistake proofing is a better preventative.

We have a similar issue at our company. Our current calibration system requires calibration of all tools, whether they be used by inspection or by the machinists. We were on a monthly calibration schedule for all hand tools, but as the company has grown, it is impossible to locate and calibrate over 200 hand tools every month, in addition to your regular duties. Recently we changed the calibration interval of shop tools to 90 days. We are still overwhelmed. One of the biggest problems is just trying to locate these tools. There are 8 machinists, and a shop foreman, most of which have about 20 tools. A couple machinists have no tools of their own, and use the shop tools. There are about 70 shop tools. Basically these tools are all over the place, sometimes locked in a machinist's toolbox, sometimes just missing. (Of course they will resurface during an audit.)
We are ISO 9001:2000 registered FAA Repair Station and have an AS9110 audit coming up. I have a few weeks to come up with a better system.

We have a similar issue at our company. Our current calibration system requires calibration of all tools, whether they be used by inspection or by the machinists. We were on a monthly calibration schedule for all hand tools, but as the company has grown, it is impossible to locate and calibrate over 200 hand tools every month, in addition to your regular duties. Recently we changed the calibration interval of shop tools to 90 days. We are still overwhelmed. One of the biggest problems is just trying to locate these tools. There are 8 machinists, and a shop foreman, most of which have about 20 tools. A couple machinists have no tools of their own, and use the shop tools. There are about 70 shop tools. Basically these tools are all over the place, sometimes locked in a machinist's toolbox, sometimes just missing. (Of course they will resurface during an audit.)
We are ISO 9001:2000 registered FAA Repair Station and have an AS9110 audit coming up. I have a few weeks to come up with a better system.


What are you basing your calibration intervals on? Do you typically find significant numbers of gages that need adjustment?

With the exception of indicators (which are used for shop reference only), we haven't had any issues with tools falling out of calibration. There is the occasional damaged tool, which is either sent for repair or removed from service, but this is usually caught by the operator at the time of use (not during calibration).

This calibration system was set up many years ago, and it is my belief that the original philosophy was to try to do "better than" necessary. (Kind of the metrological version of "over-tolerancing" on repair designs.) This was adequate when there were only about 70 tools and a manager who had a lot of extra time on his hands. Now, we no longer have that luxury, and we really have to analyze our system and revamp the entire process.

With the exception of indicators (which are used for shop reference only), we haven't had any issues with tools falling out of calibration. There is the occasional damaged tool, which is either sent for repair or removed from service, but this is usually caught by the operator at the time of use (not during calibration).

This calibration system was set up many years ago, and it is my belief that the original philosophy was to try to do "better than" necessary. (Kind of the metrological version of "over-tolerancing" on repair designs.) This was adequate when there were only about 70 tools and a manager who had a lot of extra time on his hands. Now, we no longer have that luxury, and we really have to analyze our system and revamp the entire process.

If you were doing monthly calibrations without having to do a lot of adjusting, you should be able to use the records to expand your calibration intervals.

We have a similar issue at our company. Our current calibration system requires calibration of all tools, whether they be used by inspection or by the machinists. We were on a monthly calibration schedule for all hand tools, but as the company has grown, it is impossible to locate and calibrate over 200 hand tools every month, in addition to your regular duties. Recently we changed the calibration interval of shop tools to 90 days. We are still overwhelmed. One of the biggest problems is just trying to locate these tools. There are 8 machinists, and a shop foreman, most of which have about 20 tools. A couple machinists have no tools of their own, and use the shop tools. There are about 70 shop tools. Basically these tools are all over the place, sometimes locked in a machinist's toolbox, sometimes just missing. (Of course they will resurface during an audit.)
We are ISO 9001:2000 registered FAA Repair Station and have an AS9110 audit coming up. I have a few weeks to come up with a better system.

In addition to Jim's, Helmut's and Brad's help, it seems to me that you've got a challenge with the use of the calibration system. If you have people who lock equipment away so you can't locate it, I'd suggest you need an awareness session (or three) and some other strategies for dealing with equipment which is personally owned. My belief is that any machining company that doesn't own it's tools, relying on the personnel is asking for a measurement problem. It's a false economy to do it that way and is a 'ticking bomb' in view of the transient nature of some people. They leave and so does your measuring system.....

We have a similar issue at our company. Our current calibration system requires calibration of all tools, whether they be used by inspection or by the machinists. We were on a monthly calibration schedule for all hand tools, but as the company has grown, it is impossible to locate and calibrate over 200 hand tools every month, in addition to your regular duties. Recently we changed the calibration interval of shop tools to 90 days. We are still overwhelmed. One of the biggest problems is just trying to locate these tools. There are 8 machinists, and a shop foreman, most of which have about 20 tools. A couple machinists have no tools of their own, and use the shop tools. There are about 70 shop tools. Basically these tools are all over the place, sometimes locked in a machinist's toolbox, sometimes just missing. (Of course they will resurface during an audit.)
We are ISO 9001:2000 registered FAA Repair Station and have an AS9110 audit coming up. I have a few weeks to come up with a better system.

My question is... isn't there a tools control list, especially so for those that require Calibration?
We do breakdown the equipment accountability to the technician as they are the user of the equipment. Location of tools and equipment are as per stated in the list. Bi-weekly or monthly inspection will be done to ensure they are in place. Nothing of the sort of misplacing has happened for past 4 years.

What I'm stuck on is must I identify all the other measuring devices used on the production floor during the daily work details. The guys use these during the build process; they are not used for the critical/final dimension checks. I have been told that I must mark these as "FRO" (For Reference Only). What I want to know is must this be done? I've put a statement in the procedure that indicates any tool not identified as calibrated is by default "For Reference Only". Does this statement cover us per ISO 9001:2000 or must we mark each tool as FRO?

Not sure if this works, separate the control process between the 2 sections and ensure the tools are significantly marked and not used in the critical measurement. Also, create evidence that the tools are checked before used (like verification). I believe some recordings are done for critical measurement, which in the recording form, the device serial number can be including as evidence of using the calibrated tool.

Hi again, another way is to do a reference object verification. Meaning tools sent for Calibration (for the critical measurement as required) measuring a reference object compare to a non-calibrated tool measuring the same reference object. If within the tolerance specified, should be acceptable. This must be included in the Quality process manual.

In my view point even the tools used for measuring critical dimensions are to be calibrated as they are used to assure quality standard. Hence are to marked as appropriate.