Damn. It's thursday, so I might be too late with my suggestion.
Drill through the center of the bolt.
Slowly working your way up in bit sizes.
In the hopes that once enough of the center of the bolt is gone. That the sides will compress enough to let go of their hold.
Sounds like you're loosing your butt on this one.
Thursday, December 18th, 2008 AT 8:39 PM