From another thread...
Quote Originally Posted by Rodsmachineshop View Post
I remove grade 8 bolt with my plasma cutter . put torch centered on broken bolt hit trigger for a second woosh bolt gone with clean hole with threads still there
What size bolt diameter was it????

Any other tricks on removing bolts??? Sometimes I get some that will not come out. I know an EZ out only seems to work for loose bolts. If you get carried away you can snap the easy out off and really be in a heck of a mess. Or you can swell the stuck bolt and jam it tighter. I have a friend whose father used to take a stick welder and stick the rod to the bolt and after a while the bolt would get red hot and drip/fall out. I have also heard of welding a nut onto a broken bolt. That worked a little for me. I have heard of heating them up, then waiting to cool off, then heating again helps. I know the big thing is to heat up the nut or casting to swell the hole to get it to release the bolt, not the bolt.

Bolts that are rusted or corroded in place or bottomed out in a blind hole then snapped off are always tough to get out.