QUOTE(914 RZ-1 @ Apr 27 2020, 03:38 PM)
I've tried using the bolt extractors and have broken them every time.
Throw the bolt extractors away. In the end they only cause more problems by breaking off and then leaving you with a hardened piece of tool steel in your way. The only practical way to get a broken tap or bolt extractor out is via EDM machining and that is not cheap.
1) PB blaster - days in advance
2) Heat is your friend. MAPP Gas is the cheap solution. OxyAcetylene is better. Try heating and turning it out with vice grips.
3) If #1 and #2 fail, Locate center of bolt head. Use center puch to mark it.
4) Drill out the core of the bolt with
Left hand drill bits. With any luck it might loosen during drilling but probably won't.
5) When you have about 3/16" core out of the bolt. Try heat and vice grips again. Removing the core allow some stress to come of the threads.
6) Be aware the anchor is only spot welded to the long. If that breaks free - you're absolutely screwed so don't use a break bar or excessive force!
7) If all this has failed then keep drilling outward as RZ-1 suggets until you get to the root diameter of the fastener. At that point pick out the threads and/or try to retap on-size.
8) If you've still failed, you probably will have to drill the bobbin oversize and then helicoil it.