I would like to know the appropriate way for claibrating bore gages..
Should I calibrate the whole component, with the bars, the anvils and everything..assembled..? Or can I calibrate only the dial gage..? I would be very grateful if someone can help me..Thanks so much..

I would like to know the appropriate way for claibrating bore gages..
Should I calibrate the whole component, with the bars, the anvils and everything..assembled..? Or can I calibrate only the dial gage..? I would be very grateful if someone can help me..Thanks so much..

If you're not sure about how to go about it, it's probably best to have it done by a qualified calibration lab.

If you're not sure about how to go about it, it's probably best to have it done by a qualified calibration lab.I agree! Plus, it may be time to check your definition of what YOU mean by "calibration" which you should compare with "certification" to NIST Standards.

Almost always, the mere fact one asks such a question is a strong indicator the person asking is not clear on what really needs to be done.

Most metrology experts would cringe in a manner similar to a brain surgeon cringing when someone asks what size hole saw to use to open a patient's skull.

why?

We have saved lots of money by calibrating instruments inside..
I have temperature and humidity control, an analyst very well trained, good work instructions.., good masters , We are a machining factory, we have hundreds of different kinds of instruments therefore, we are really saving a lot of money, because several instruments are very easy to calibrate..

Anyway, I still have that doubt, because some people in the plant have complained to us..when they see that we disassemble the bore gage to calibrate it and we only calibrate the dial gage.I tell them that the accesories does not have any kind of identification, I mean, that there is no traceability, and because of that it is possible to interchange them with any dial indicator and in that way it is impossible to know if the calibration has been made with a specific group of accesories , that is the reason why I calibrate only the dial indicator.
But, I am very interested in knowing other opinions..I would be very grateful if you can help me with further information

and anyone know how a certified calibration lab do it?....

If your company qualifies, you can join www.gidep.org (http://www.gidep.org) and obtain calibration procedures.

I would like to know the appropriate way for claibrating bore gages..
Should I calibrate the whole component, with the bars, the anvils and everything..assembled..? Or can I calibrate only the dial gage..? I would be very grateful if someone can help me..Thanks so much..

hiiiiiiiiiii

i think you should concentrate on the IS for bore gauges related information.

we used to calibrate in assembled condition.
You can use a ring gauge for internal calibration.

If you have elctronic probes you may go for calibration with ring gauge using TIR method, but probe calibration is must in it.

Ring gauges for calibration you can get from good instrument manuf organization or prepare inhouse

just dont forget to get it hardened chrome plated to minimise the rate of wear.

one more thing if you calibrate it by ring matster gauge you need not get it calibrated from external lab if your master ring is calibrated from NABL / IEC 17025 accredated lab.

i will provide you in detail knowledge in a few hours as i am a bit busy

At present I calibrate only the dial indicator with primary calibrated block gages..

If I calibrate the complete bore gage as you say with master rings I should have hundreds of different master rings..because I must calibrate in 0%, 25%, 50%, 75 % and 100% of the total range of the instrument and in that way you have lots of possibilities because each different accesory gives a differente range of measurement to the device, I cant imagine dealing with such a complexity..

anyones hasa procedure or work instruction?

At present I calibrate only the dial indicator with primary calibrated block gages..

If I calibrate the complete bore gage as you say with master rings I should have hundreds of different master rings..because I must calibrate in 0%, 25%, 50%, 75 % and 100% of the total range of the instrument and in that way you have lots of possibilities because each different accesory gives a differente range of measurement to the device, I cant imagine dealing with such a complexity..

anyones hasa procedure or work instruction?
Calibration should include the entire gage. So what if the dial indicator is calibrated. If the anvils are worn or damaged, the bore gage will have bias regardless of whether the dial indicator is calibrated or not.

At present I calibrate only the dial indicator with primary calibrated block gages..

If I calibrate the complete bore gage as you say with master rings I should have hundreds of different master rings..because I must calibrate in 0%, 25%, 50%, 75 % and 100% of the total range of the instrument and in that way you have lots of possibilities because each different accesory gives a differente range of measurement to the device, I cant imagine dealing with such a complexity..

anyones hasa procedure or work instruction?


if thats case

you can use the calibration setup's from different manufacturers like LVDT based etc.

Questions for Bore Gages: What type of bore gage are you using? Does it have a three point measuring head or two? Does it have a removable dial indicator? Does it have setting rings with it?

The previous suggestion of GIDEP is a good one. They have a nice procedure that I would like to attach except that that would be a federal crime! If you have 1 military contract, go to www.gidep.org and sign up for free.

We are an accredited lab for bore gages. For a threee point measurment device, we specifically make a note on our accreditation scope that if the gage has a removable dial indicator, that we will remove it and just calibrate the indicator. We will then peform a function test of the bore mechanism and fixtures.

If the gage has two points, we will use an id stack of gage blocks and calibrate everything.

If the gage has setting rings, we calibrate those and use the rings to check the bore gage.



If the gage has setting rings, we will

The previous suggestion of GIDEP is a good one. They have a nice procedure that I would like to attach except that that would be a federal crime! If you have 1 military contract, go to www.gidep.org (http://www.gidep.org) and sign up for free.
Unless the rules changed, if you supplied to a company that supplied to the US government, you could join for free. This meant that any supplier of GM could join.

I would really like to know the opinion of some professional who works on a specialized lab..

Anyone there..?
Anyone has sent a bore gage to calibrate in a lab?

I would really like to know the opinion of some professional who works on a specialized lab..

Anyone there..?
Anyone has sent a bore gage to calibrate in a lab?

Yes yes! We are here, and many of my Fellow Covers have tried to help you. :yes:

The most obvious response to your request would be: "Have you talked to the manufacturer of the bore gage?"

In addition, most equipment comes with operating- and calibration information/instructions.

Many organizations use these types of gages. Your best bet is, and just to make sure, is to go to the source.

Stijloor.

I would really like to know the opinion of some professional who works on a specialized lab..

Anyone there..?
Anyone has sent a bore gage to calibrate in a lab?

......................We are an accredited lab for bore gages. For a three point measurment device, we specifically make a note on our accreditation scope that if the gage has a removable dial indicator, that we will remove it and just calibrate the indicator. We will then peform a function test of the bore mechanism and fixtures.

If the gage has two points, we will use an id stack of gage blocks and calibrate everything.

If the gage has setting rings, we calibrate those and use the rings to check the bore gage.

Have you missed the above response? It's from the Lab Manager of an accreditated lab for bore gages.

I would recogmend calibrating the indicator and then the bore gauge as whole system/unit. You could always put a tamper eseal on the gauge to verify the indicator hasn't been changed. We calibrate bore gauges with master ring gauges and also with a bore gauge calibration fixture (developed in house).

People with more knowledge than I have answered but I will tell you how I accomplish the task.

I have many (close to 40) different size bore gages. I use Mahr Federal Maxum gages and Marposs E4 column with M1 Star handles. I have always calibrated my bore gages as one solid piece (yes they can be interchanged but no one but the gage lab is allowed to do that, so they would be re-calibrated).

My method of calibration was to certified NIST traceable gage blocks and certified Nist traceable parrallel bars. I would place the bars in a vice and stack the blocks to the correct minimum and maximum size and take readings on the bore gage. This was very time consuming so I started purchasing minimum rings and maximum rings (always have nominal rings with the gage). This made the process go a lot faster and in the long run saved money. Now that is not to 25%, 50%, 75%, and 100% of the tolerance but it allowed me to check nominal, min to that specific bore gage size, and max to the same size. I have never had an auditor find any problem with either method that I used. We are an automotive supplier and are audited to ISO and 17025 so I cannot speak on other areas of manufacturing but what I deal with daily.

Hopefully this will give you some idea what is possible. Another point is that the rings are calibrated to an outside source. I have the equipment to do the rings but it also is time consuming so I am still sending them out.

Dale