[undy]

You're going to have one he!! of a time getting that out. I don't know if a cobalt drill is going to do the trick. Those extractors (even the cheap ones) are very h-a-r-d. I don't know that I wouldn't go immediately adjacent to the broken bolt and drill/tap a new hole and forget about the broken one.It's sort of a jack-leg thing to do but it would end up accomplishing the same thing.

Dave