This Problem Has to be Magical...
...because it sure as hell doesn't conform to any laws of God, nature or science.
I have chainring wobble- every revolution, boths rings swing outward slightly. I've tried two different cranksets (one of which has a one-piece carbon crank and spider) so I think I can safely rule out a bent spider, which was my LBS mechanic's opinion.
I've tried both cranks on two seperate bottom brackets (I use ISIS)- same problem, so I don't think it's the bottom bracket.
Both bottom brackets thread in easily, I can tighten the drive-side flush to the frame by hand.
At this point I'm thinking it has to be either odd threading on the frame, or the bottom bracket tube was welded crooked. (It's an '06 Cannondale CAAD8)
Or maybe it's magical and elves did it- I'm stumped. Any thoughts?