Surprisingly,
We use the Chuck Nickloy method--or variations of it.
Usually we will heat up the bolt red hot and then let it cool. We help it along by touching a wax candle on it and you would be amazed to see the wax wick down the threads.
We then tap rather hard on the bolt with chisel several times.
Drive in the torx bit and have fun.
When things get ugly, I weld a hex headed bolt onto the bolt and then very carefull back it out with a wrench--going back and forth.
When things get really, ugly...I bought a tap disentigrator. Burns the bolt right out an leaves the threads.
David
