Yeah, I'm sure it's 9/16 and since you tapped them, you know they are!! And Lowes, Home Depot, Sears and Northern don't carry tap/dies that size - unless you want to buy a full $129 kit at Sears :shock:
I cleaned the crap out of them again and spun the studs in without too much effort. Took the wrench, but didn't thread the lock nut - so not difficult.
So, as I was fitting it all back together ...

Found the next problem ...

ARRRRRGGGHhhhhhhh 🙁:
The spacer, once installed, is wider than the knuckle and won't allow the brake plate to fit. Just said f*@k it and odered the arms from Ballistic fab - they're having a Labor day sale :!:
More delay, but I can work the brake MC issue I guess :-|
Going to go practice with the bow and have a few beers :razz: