Help Stuck Key in Rear Dually Hub

[adis]

Can someone offer advice on how to get a stuck key out of the rear hub on my 80 dually? I want to look at the brakes but cant do anything until I get that little bugger out. I've tried a magnet, patiently tapping from side to side with lots of WD40 (it moves and the lock nut moves as well), I tried heating it with propane, I tried drilling into it to tap a screw, I tried welding a nail on to it, I tried cutting the retaining lock nut - nothing has been successful and I've spilled two beers and cut my thumb and am getting to the point of "hulk smash." I think that maybe it might have been tapped in and the back side might be mushroomed a bit? I can't figure how it is stuck in there. Thanks for any ideas? - mark