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I saw this in YTMAG. Removing Broken Bolts Another great discussion from the Tool Talk Discussion Forum. The discussion started out with the following post: " How would I remove a bolt thats broken off in a piece of metal and I want to save the treads in the metal and then put in a new bolt. " What followed are some interesting replies: " I have had good luck with the following method- heard about it several years ago and never would have believed it until I tried it. It works best if there is some bolt still sticking up where you can get ahold of it. Here goes: 1. Heat the bolt only first, then let it cool naturally.
2. Heat the area around the bolt AND the bolt at the same time.
3. While the bolt and surrounding area are hot, get an ice cube and put on the bolt ONLY. BE CAREFUL-WEAR GLOVES FOR PROTECTION.
4. Normally, if you can get a pair of vice-grips on the bolt, it will spin right out. No drilling required. Hard to believe, but it works. Try it. " " Drill a hole in the middle an weld it shut with 6013 then weld a nut on it ,and turn it out because it shrinks the bolt. " " All good advice, what I usually do though, is drill a hole in the bolt using a cobalt or titanium nitride bit. They cut better in higher grade bolts, but use lots of lubricant. Then I heat the bolt with a torch until it's red hot. Then, walk away and do something else until it's completely cool. The expansion and contraction will usually free up the bolt enough to make an easy-out effective. If this fails, I get out the trusty die grinder. Good luck! " " You can use an easy out. All you do is drill a hole (the size wil be given on the easy out) then screw in this thing that looks like a drywall screw with very coarse threads. They run opposite of the bolt threads, so the tighter you turn, the better the grip. You can also weld a nut on the end. The heat from welding will help loosen it up, as well. " " If you are going to drill a hole use a reversable drill with a left handed bit. Sometimes you get lucky and the drill bit will spin that bolt right out. " " Be careful with the easy-out. If the bolt was stuck enough to break off, it's usually stuck enough to break an easy-out, and then you have BIG problems. If any of the bolt is sticking up where you can get at it, welding on a nut works fairly often. Also, before trying anything, get some penetrating oil, such as Kroil or Liquid Wrench, and soak the area good and tap firmly on the bolt off and on for a couple of days. " " There's also another method that works, but "It Ain't Cheap" and is mentioned in case you have a one of a kind thingy that can't be replaced and money is not the issue (I had it done once on an engine block and the chair I was sitting in still looks like it was set up for pulling a gooseneck trailer). It's called E.D.M. or electric discharge machining. It really can burn an exotic alloy bolt out of a much weaker metal without damaging the weaker metal (seen it done or I wouldn't have believed it). "
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