We just passed our ISO 9001:2000 annual audit with one minor. The minor was for a disconnect between the customer print, and our inspection criteria. Long story short... what I need is a standard sheet steel gage and tolerance chart. Our customer does not give us a tolerance for material thickness, and they do not refer to any standard. Does anyone have anything out there that might be of help?

Congratulations on a successful audit! :applause:

What do you make? Do you do things like manufacture cold rolled steel? Are you measuring corrosion - or the resulting thickness afterward?

Tolerances are listed on prints, in contracts, and/or in other specifications. I can point you to a gauge-to-inch thickness chart like this one (http://www.benjaminsteel.com/Technical%20Data/sheet-thickness-chart.htm), but tolerances are generally specific due to needs of fit, form, function and appearance. So I'd like more information please.

We manufacture stamped, laser cut, and other steel fabrications. We use steel from 16 gage to 1.25" thick. Our issue was that the print calls for 0.172 steel, but does not specify a tolerance. We quoted, and are making, it out of 7 gage HR steel. The auditor did not like the fact that we saw it two different ways (sales saw it as 0.172 min, quality saw it as 0.172 nom). Is there a chart that shows standard mill thickness tolerances based upon standard thickness?
I see that I did not give all the info needed! Sorry!

Does your supplier offer a tolerance for the thickness of their material? Does the material have a certification? Might be handy to go to them if the customer is not concerned. :cool:

Bobdoering is right - since you are not manufacturing the steel, the thickness tolerance isn't yours to control, but perhaps to verify. However, if the customer does not care about a tolerance you could state as much somewhere to close the information gap.

Isn't there a default tolerance on the customers print. Ex....X=.015, .XX=.01, and tightest .XXX=.005"? If not then I would think your man. eng/QA eng or Eng department would have such a default. The other recourse is that when these issues arise they are taking in consideration in the planning stage. If not on the print contact the customer before product is released to manufacturing. Then just document the results.

Good luck

Thank you all for your input.
1. I will get a letter from the customer as you stated Bob.
2. There is a standard block tolerance, but that will put the material between two different specs (7&8 gage) the block tolerance would give us 0.030!
I was hoping that there was a quick reference chart that I could hang in our QC area to kill this issue.
Then I just have to go thru our system to ensure that we do not have this issue with anyother cusomer!

Do you order to something like an AMS that might define the mil run tollerances?
While the firm you are buying from is probably no more than a distribuitor the actual mfg of the sheet stock has tollerances defined some how.
:2cents:

We are getting certified material (chemical and physicals) for each shipment. We are getting it from a middle man (Steel Wharehouse). I have a wallet card from Charter Steel that states the mins and maxes for each different gage, which is what our sales team uses to quote. We are going to have to start talking with our sales guys more to ensure that we are checking the same thing that they are quoting.

We just passed our ISO 9001:2000 annual audit with one minor. The minor was for a disconnect between the customer print, and our inspection criteria. Long story short... what I need is a standard sheet steel gage and tolerance chart. Our customer does not give us a tolerance for material thickness, and they do not refer to any standard. Does anyone have anything out there that might be of help?

Hi jdtrixler-

I assume you work with commercial quality steel. I have attached a sheet showing industry standrd for different material gage and type - this should help a bit.

Thanks Carol, that is what I already had from our sales people, but I could not find it anywhere else! What about the thicker material, i.e. 1/4 or greater? How does that fall into the mix? We have typically used (not to purchase, or receive, just as a double check when running) +/- 0.010. But it looks like we will have to break this habit!

Thanks Carol, that is what I already had from our sales people, but I could not find it anywhere else! What about the thicker material, i.e. 1/4 or greater? How does that fall into the mix? We have typically used (not to purchase, or receive, just as a double check when running) +/- 0.010. But it looks like we will have to break this habit!This supplier (http://speedymetals.com/information/material29.html) lists .030" tolerance for 1/4 inch plate.

The tolerances should come from your supplier(s). Since you get what they send you, unless your customer lists special requirements I would list the tolerances in your documents as your supplier does.

Thanks Carol, that is what I already had from our sales people, but I could not find it anywhere else! What about the thicker material, i.e. 1/4 or greater? How does that fall into the mix? We have typically used (not to purchase, or receive, just as a double check when running) +/- 0.010. But it looks like we will have to break this habit!

You are very welcome. I would ask your service center rep what the mills use for tolerances - I know we typically see 1/4" plate come it at .240", but we really don't sweat that stuff.

Have you check The Machinery Handbook? It might have info on plate thickness and tolerances.

Your engineers should be helping with this kind of question.

When there's a specification information gap for a fabricated raw material, it's respected engineering practice to try to get the involved parties to agree to use the most applicable industry standard. Then at least you'll be using thickness nominals and tolerances that will correlate to those of commercially available materials, and your purchasers will be able to buy available products.

In the case of rolled steel, the dominant US industry standards organization in regard to setting standards for shape thickness nominals and tolerances is AISI (www.steel.org (http://www.steel.org)). You'll probably find that any chart of commercial nominals and tolerances, such as what your steel center might give you or what you'll find in Machinery Handbook, will be derived from an AISI reference. Note however that many steel mills offer better-than-AISI tolerances as normal practice. Weirton Steel, for instance, normally offers Hot Rolled Carbon Steel at 3/4 AISI. They'll accept some orders for 1/2 AISI, depending on product.

Thank you all for your help on this topic. What we ended up doing, and what was excepted by our customer, was to dig into the ASTM specs and use them as our guideline. What we found was that for thinner material ASTM A568 was the guy to go to. ASTM A568 is the general info for steel sheets.
Then for the thicker items we found to use ASTM A6. This is the same as A568 except for structural steel.
Both of these ASTMs have thickness tolerances for given sheet size, and process in which the material was made. They are written like most other specs that I have read, in a circle, but are very informative.
I hope if anyone else is reading this because of the same question, that this new info here helps!
:thanks:

... I hope if anyone else is reading this because of the same question, that this new info here helps!
It no doubt will - thanks for the update!!:agree: