The adapters are 1/2" thick and
zinc coated. Since one of the adapters was so wildly warped, about 1/16" across the 6" diameter, I'm thinking that they might be heat treating the adapters and causing them to warp. It's hard to tell if the adapter faces are even machined with the coating they have on them. I get the new adapter today so I'll mount it up and see what the runout is and make some decisions based on what I find. If the new one runs true I'll send the other one back and hopefully get a true replacement.
Kim