just saw this. a good torx bit makes a pretty fair extractor. they have straight shanks. the wedge extractors expand the threads where they go in. I have very good luck with torx bits, a little heat and a can of air duster spray. heat around broken part , turn air spray upside down propellant will come out. use this to freeze stuck fasterner , use torx bit. IMO this is a much better method than welding as a first step. welding is a last resort, because once you weld a nut drilling is no longer an option. I have better than 90 % success with this method. snap on sells an excellent pipe extractor set, made by ridged. this is my next step. hope this helps .