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Up Topic American Welding Society Services / Technical Standards & Publications / calibration
- - By mall Date 02-24-2016 05:03
hi all,
ive been searching for a while and found nothing or missed it.
what is the standard used to calibrated cam bridge gauge, weld fillet gauge, v-wac?
Parent - By welderbrent (*****) Date 02-24-2016 06:29
WELCOME TO THE AWS WELDING FORUM!!

Some gauges can be 'certified' as to accuracy but not 'calibrated'.

To be calibrated there must be a way to adjust the zero. 

A company QC policy should state how and how often this is accomplished.  Usually some form of machined block for total flat line adjustable positioning on the bridge cam.  Weld fillet gauges and v-wacs can be checked for conformance to industry standard using a 'certified' set to see if they are worn or damaged but generally can not be 'calibrated'.

He Is In Control, Have a Great Day,  Brent
Parent - By another1 Date 02-24-2016 15:20
A small certified surface table and a couple of gage blocks with certs can take care of a lot.  This gives you some traceability.  Granite surface and ceramic block will last indefinitely, but steel will rust if not always rigorously maintained.
Parent - By pipewelder_1999 (****) Date 02-25-2016 11:10
I had a small block manufactured that contained steps, holes, chamfers etc. and had the mfg document all of the dimensions using a measuring system traceable to NIST standards and document the measured dimensions on the drawing along with a signature and references to the machine used.

I then have a "working standard" that is suitable for the degree of precision established within our quality policies and supporting procedures. It also works for tape measures, steel rules, micrometers, calipers etc... . My next one will be slightly larger because its a pit tricky for the base of the bridge cam gauge.

Have a great day.
Gerald Austin
- - By mall Date 02-24-2016 07:46
does that mean there is no reference standard to certified thiis kind of equipment?
Parent - - By 60John (*) Date 02-24-2016 13:08 Edited 02-24-2016 13:11
I use the 3,4,5 method to calibrate a framing square( 2' ) using 12" 16" and 20" between points and measure the 1st 1" using a calibrated tape measure. That will do the cam and weld gauges. Gage blocks will do the v-wac gage everything should be traceable back to a national standard. I was told by AISC in the past it didn't have to be an American standard just a national standard (the reason I asked them as we had metal shims from Germany for the dft gauge calibrated to the German national standard and we had an audit coming up).Plus what Brent said weld fillet gauges toss them if out of the tolerance you or your company set.
Parent - By jwright650 (*****) Date 02-24-2016 20:53
When I was a QC manager for a small fabricator, I survived many years of AISC audits like 60John stated by using  calibrated fillet weld gages from Gal Gage and compared the shop gages to the certified gage....same with the tapes used with a tension pull handle and framing squares(again the 3,4,5 rule works for compliance).
- By 803056 (*****) Date 02-24-2016 19:10
There is no national standard I know of for fillet gages. I believe GAL certifies their "certified" gage to be plus or minus 0.004 inch.

Your employer should include a statement regarding the required precision of fillet gages and other gages used for production work and perhaps a slightly more stringent precision for final inspection. As mentioned in a previous post, the gages can be checked with a $40 surface plate and gage blocks.

Fillet gages are typically in 1/16 increments for small weld sizes, 1/8 inch increments for welds larger than ½ inch. The required precision is dependent on the welding standard, but none of the more common standards place limits on welds that are too big.
That being the case, check the gages to see they are measuring welds as being larger than they actually are. In other words, if the gage is stamped as 3/16, the gage should be no less than 3/16, but if it a 1/64 inch too big there is no fowl.

GAL will make special gages to order. They will make fillet weld gages in 1/32 inch increments for the right price. If the contractor has the necessary equipment, i.e., a laser cutting machine, they can make their own gages. Most lasers can hold the required accuracy to produce gages with the necessary precision for fillet gages.

Undercut gages, that is a different story. There is a pivot and a hole, either of which can be positioned incorrectly or the hole might get worn (in a thousand years of use) to the point where it needs to be replace. Again, the surface plate and gage blocks will provide the necessary information whether to replace the gage or not.

The best thing to do is put a system in place before some anal QC/QA auditor gets involved and screws up your entire manufacturing operation.

Just my thoughts.

Al
- By mall Date 02-25-2016 01:27
thanks for this info.
its help a lot!
Up Topic American Welding Society Services / Technical Standards & Publications / calibration

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