Need help getting rusty grade 5 bolt out of stainless steel.

[DarkBlack]

Back in the dark ages I helped a bud with one like that. We ground the broken bolt flat, then drilled and tapped.

That’s never the best solution in my experience. Unless you over size, you’re all but guaranteed to drill/tap into existing threads, with partial old threads falling out and an oval shaped loose finished hole

 

[sixdogs]

Back in the dark ages I helped a bud with one like that. We ground the broken bolt flat, then drilled and tapped.

I'm lucky I had enough if a stub to heat and then grip onto with a pipe wrench. Otherwise I would be trying to drill a part with a curve in it.

 

[RV1]

That’s never the best solution in my experience. Unless you over size, you’re all but guaranteed to drill/tap into existing threads, with partial old threads falling out and an oval shaped loose finished hole

I agree. Lately I would weld a nut onto a broken stud, even if the stud is flush to the piece around it, welding in the center of the nut to make good contact. Then I put a wrench on it and back the broken stud out. The welding heats up the stud and helps it to break loose and the nut gives you something to put a wrench or socket onto. If the weld breaks, grab another nut and try again.

 

[CalG]

OK, soft flame however.

On these two broken off cap screws, I used a rock hard flame, reheated to red hot multiple times, and then welded on a nut to turn them out.

Welding on the nuts assured they were good and HOT ;-)