Fastener/Hardware Specifications - ISO 2

[AMontembeault]

We're looking at revamping our methods of controlling hardware in our CAD modeling and drafting processes. As we're going through this effort, we've been digging into the relevant standards (typically DIN, Iso, etc.) to understand tolerances, naming conventions, and so on.

Reccently, when working with some washers, manufacturerer's literature generally indicates that the washers are compliant with ISO 7089, which seems to have consolodated the old DIN 125 standard. Where we're running into some confusion stems from material choice - go to any vendor, and they'll tell you a brass washer complies with ISO 7089, but if you look in the actual standard itself, only steel and stainless steel washers are referenced.

So we're a bit confused as to how materials not specified in the standard can still pertain to this standard - has anyone else run into this? How did you resolve it? Am i just missing something in the overal ISO standard system which makes this possible?

Thanks

 

[MintJulep]

Simple answer is that you are right and vendors are wrong.

Longer answer:

Way back (circa 1968) DIN 125 was dimensional only (I think, can't find a copy anywhere)

DIN 125 was superseded DIN 125-1 and 125-2 that added material requirements for hardness and possibly other properties.

At some point those morphed into DIN 125-A and 125-B, maintaining the hardness requirements.

And finally those were replaced by ISO 7089 maintaining the hardness requirements.

So these brass washers meet the dimensional requirements of the 48 year only, long ago withdrawn DIN 125.

But tracing the history of DIN 125 typically results in "Superseded by ISO 7089"

So you end up having soft brass washers that match the dimensional requirements of ISO 7089, but not the hardness or other material requirements being advertised as "Complies with ISO 7089".

Which is exactly why certificates of compliance are worthless.

 

[Tunalover]

If you can get your hands on a Bossard catalog you'll be in luck. It references all the ISO and DIN standards governing fasteners. With that you'd need nothing else. Part nos can be constructed that are universally understood.

Tunalover