"jonnie.nightbar" wrote in news:PMXTa.640$ snipped-for-privacy@newsfep1-win.server.ntli.net:
I read on welding group that the way to tackle this one is to place a nut over the top of the bolt and stick weld through the nut onto the bolt, i.e. weld the two together "from the inside".
Apparently there is a special welding rod for this job. Your friendly specialist welding supplier may know. Then simply get your spanner and unscrew. The heat of the welding helps loosen the bolt. Or so they say. Note: I've never tried it!
Derry