Gage Block Calibration Frequency Requirements

[velazedv]

Hi, I have a steel gage block set of 81 pieces and grade B, I keep them protected and they have no wear, surface condition or damage to gage surface.
They were calibrated in 2003 according to NIST 821/261776-99.
If I visually inspected every year, can I use them without send them to calibration???
I only use them to calibrate/verify in-house (once per year) our calipers, micrometers, dial indicators and dial gages.

Any ideas or help????
Thanks

 

[Stijloor]

Re: Help with Gage Blocks

Welcome to The Cove Forums!!

Visual inspections do not provide evidence of dimensional characteristics. Your calibration process should have information at what frequency this set has to be calibrated. Every year? Every 3 years? Every 5 years?

You can not leave that open-ended.

Stijloor.

 

[Jen Kirley]

Re: Gage Blocks Calibration Frequency Requirements

Welcome to the Cove!

As always, Stijloor is correct. What are these gage blocks used to inspect? When we inspect with a traceable standard like gage blocks, the people who buy our products generally expect we have developed a schedule for maintaining the certainty of these standards, traceable to a national standard.

Since it sounds like you don't use these standards rigorously or often, their recalibration* schedule may reflect that fact - little wear means infrequent need for the re-validation of calibration. Depending on your products, needs and customer/industry expectations, your schedule could be one, two or more years apart. But I think If I was the customer, 7 or 8 years is too long.


*As we in the Cove have exhaustively discussed, for gage blocks the term "calibration" can mean validating because no adjustment is needed, yet the accuracy must be confirmed via comparison against a higher-level, nationally traceable standard.

Please also be aware that it's generally expected that we keep records of this calibration, and we have an established (usually written) process or method for determining the schedule.

 

[sbn510]

Re: Gage Blocks Calibration Frequency Requirements

Is it acceptable to place calibrated gages on the shelf and issue say five years from the calibration date. This blocks or gages would be past the due date and frequency interval? Thank you for your replies, this will settle an argument.

 

[AndyN]

Re: Gage Blocks Calibration Frequency Requirements

Is it acceptable to place calibrated gages on the shelf and issue say five years from the calibration date. This blocks or gages would be past the due date and frequency interval? Thank you for your replies, this will settle an argument.

No! If your process requires them to be calibrated before the 5 years and they aren't, then you are not in compliance with your process!

However, if your process says you can write a "Calibration Extension" and record and authorize such a situation, then that's a better way to manage it.

Also, if they are not required to be calibrated for 5 years - reasonably - why would they be over due?

 

[BradM]

Re: Gage Blocks Calibration Frequency Requirements

Depending on the mfg. and specific composition of the blocks, there is expansion/ contraction. So even if there is no excessive physical wear, it's a good idea to get them verified.

 

[dv8shane]

Hi, I have a steel gage block set of 81 pieces and grade B, I keep them protected and they have no wear, surface condition or damage to gage surface.
They were calibrated in 2003 according to NIST 821/261776-99.
If I visually inspected every year, can I use them without send them to calibration???
I only use them to calibrate/verify in-house (once per year) our calipers, micrometers, dial indicators and dial gages.

Any ideas or help????
Thanks

It all depends on what your customers require and what your current quality system defines. Do you clean them, have any been dropped, these are just a few things to consider. I personally can not see justification for more than a 5 year interval if you are using them to verify other tools.

 

[AndyN]

Let's not overlook the practical reality...

Gauge blocks are very precise. They are usually employed to calibrate something at a 4:1 or even 10:1 ratio. This usually means micrometers and suchlike, which resolve to 0.001mm (for example)

It is unlikely, within normal storage (on the shelf) as the most recent poster (sbn510) asked, that they will NOT change in any manner to corrupt the calibration result.

Of course, if they are used during that 5 years, then all bets are off!

 

[sbn510]

Thank you all for your responses. Your thoughts are the same arguments I've made. A quality technician keeps espousing this theory. I wouldn't spend the money on a new gage and put it into storage for use 5-10 years later. If it's an old gage, it isn't new. Must be calibrated. It can't be stored for a period and magically become new. The first thing any machinist would do regardless of type would be check the gage before use. In other words calibrate or certify. If it were food, well just like the technicians theory, it would stink.

 

[Mr.Happy]

Hi, I have a steel gage block set of 81 pieces and grade B, I keep them protected and they have no wear, surface condition or damage to gage surface.
They were calibrated in 2003 according to NIST 821/261776-99.
If I visually inspected every year, can I use them without send them to calibration???
I only use them to calibrate/verify in-house (once per year) our calipers, micrometers, dial indicators and dial gages.

Any ideas or help????
Thanks

Why do you need a set of 81 pieces
Mitutoyo has a special set for calibration of calipers (516?124?10) and allso for micrometers (516?107?60)
I suggest that you send them out for calibration every 5 years (depending on the intensity of use).