Resistance of two clamped chunks of metal

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Sorry. I don't recall the details, just that it had 1 bolt. Art

Correct. And maintaining design pressure as temperature varies (different coefficients of expansion) is important as well.

The OP should Google "belleville washers".

Paul,

Yes indeed. We're already looking into Belleville washers, wave washers, and other similar springy things to keep the pressure constant and make the connection more foolproof for installation in manufacturing and in the field.

What I'm searching for is some type of spring washer that will provide (relatively) constant force of about 100lbs over 0.100" displacement. There are some fancy devices available, but I'm looking for something simple. Belleville washers provide a standard F=kx type of response. That will work, but I would prefer constant force due to our method of clamping the two bars together.

I've done some initial testing. With about 100lbs of clamping force, two 1" x 1" (uncleaned) copper surfaces develop about 0.6mV at 50A (or 12uohm). So, if the resistance stays put at 500A then my losses will be acceptable in this 12V system.

Bob