Class 12 metric washers? (also posted in structural)

[Ibreakstuffdigitally]

Hello, I wasn't sure where best to ask this so I've also posted this in the structural forums...

My understanding is that to prevent creep, even at moderate temperature, it is desirable to use a class of washer that matches that of the bolt. In the past, we have used class 12 washers when needed, to match class 12.9 fasteners.

Recently, it has become difficult to obtain 12.9 fasteners, and all but impossible to obtain matched washers.

Is there a reason for this?

Does anyone know of a source for these parts? Our only option seems to be having a very small run of custom hardened parts made, and this is going to be costly.

Our previous suppliers now carry 10.9 only.

Thanks in advance for any help

 

[Philrock]

You may be able to find high-strength washers from tooling supply companies like Carr-Lane, Jergens, and Reid Supply. They may not be "officially" rated class 12.9, but may still have adequate properties.

 

[diamondjim]

Do the bolts have to be metric?
We must have domestic sources for
inch size bolts and washers in a
higher grade. What sizes do you
typically order?

 

[Ibreakstuffdigitally]

unfortunately, these are replacements for existing parts, so metric is a requirement

In the future, we are likely to limit ourselves to 10.9 wherever possible, since the 12.9 fasteners are becoming such a hassle

about 50% of our fasteners must be metric,