Cutting and easy outs

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Ok, so this isn't really off topic, but maybe it is.Broke off a bolt today in a very important project.  Doing some restoration work and I really messed up.  The bolt was out.  I put anti-seize on it and put it back in.  All was ok till my last turn, then it snapped off (it was old and rusty).  Remember, I never claimed to be smart.  So, since it had anti-seize on it, I figured I could drill into it and use an easy out fairly easily right?  Nope, easy out snapped off and now I have a huge problem.No, acess from other side is not an option.  There's about 1" of the bolt and the whole think is countersunk into cast iron about 1".  WOuld one of those carbide tipped bore dremmel type things work to get this out?  It's too big of a piece to put in a drill press etc, but this is driving me nuts.Any thoughts?
Reply:I am not sure how you are going to get it out,, but a carbide wont work.  We use new bolts and thats one reason why,, tap holes first.  Is there enough thread to use a shorter bolt?  Is this in a head?  Manifold still on?Last edited by Sberry; 03-09-2004 at 02:40 AM.www.urkafarms.com
Reply:What is the diameter of the bolt?Appreciation Gains You Recognition-
Reply:Can you post some pictures?
Reply:Presuming: the hole is large enough to get into (doesn't need to be very large) and you get get the part to a shop, the easiest way to get the easy-out out is EDM.  Other things I have used: Diamond point on a dental drill-- very slow, but effective.  Work the flutes, not the bolt. Acid flush--good with aluminum castings, iffy with steel and cast. Dilute nitric preferentially etches ferrite, and even a fairly short etch will break up the surface of a tap or and extractor enough to remove it. Unfortuantely, not real good in cast iron. If you can re-thread or use an insert, this might be an option. Use a syringe to flush the acid into the flutes of the extractor.In a large bolt, it is possible to drill along the flute of the extractor and spread the bolt and work broken bit free. Often requires drilling into the threads.DO NOT try to chip it out. Any impact will wedge it in harder, also spreading the bolt and making that tougher to get out as well.  Make note for the future: Easy-outs are not real useful, in particular if you drilled with a standard bit. Tend to spread the bolt at the top and wedge it into the hole, then snap off. Try to use a left hand drill bit for drilling these, as the right hand often jams the bolt so tight it won't come out. Lefty bits often walk the bolt out without the extractor.
Reply:Wow, sorry, wasn't expecting this much help.  I guess my next purchase needs to be a digital camera because taking pictures and waiting to get film back for the whole roll takes way too long.It's a 1/4" diameter bolt, that is very old, and has surface rust.  Length was about 2".  The last 1" broke off and is all the way in.  Basically, I over-tightened it (again, never claimed to be intelligent).  The easy out broke off almost flush with the bolt, which means there is less than 1/32" of a lip sticking out - tried needle nose to no avail.This is in a piece of 60 year old machinery that I'm trying to restore - it's really embarrassing too.  Feel like a real moron.  I have actually never heard of a left hand drill bit till now, but I can assure you that I will get some if I can find them.Thanks
Reply:Mig weld a washer over the bolt. Then weld a nut to the washer. I have done this to  a sheared off 8-32 screw.
Reply:It's recessed too far in to weld it.  This is only a 1/4" diameter hole and the hole is 1" deep before you reach the bolt which itself has about 1" of it lodged in there.
Reply:Here's a drawing of what I have - maybe this will help.  I'm sure it will get a few chuckles.I tried to borrow a camera, but the pictures were not coming out. Attached Images
Reply:What's the base metal?  In steel for example, you only need about 1.5X the bolt diameter to prevent stripping the threads.  For 1/4" bolts this is a 3/8" deep tapped hole.For aluminum, I typically use twice the diameter, or 1/2".
Reply:Thanks Aaron, this is into cast iron (about 50 year old).  You mean 50% of the bolt diameter not 150% right?
Reply:Hey, that is a good drawing.     If this is real important I would have it done with an EDM machine. I have heard of using a cutting torch to blow out a broken bolt in cast iron. It is not supposed to hurt the threads.Hmmmn.....I wonder if you had a copper sleeve that would go in the hole.......and then slid in an arc welding rod and arc it to the top of the bolt. Maybe yes, maybe no.
Reply:EDM is best and most accurate.  Another thing you can do is use a carbide drill or 2 flute end mill, which should be able to drill thru the whole thing.  You will probably not be able to do this by hand since the mill will want to walk into the cast iron.  Assuming you don't have access to either, can you drill a hole on either side of the broken bolt and make a little spanner wrench to fit down into the hole?  This assumes what's left of the EZ-Out won't interfere.  You probably can't go bigger than 3/32 since this is 1/4 hole.  Let the drill bit wander to one side and chew out some of the threads then make a spanner to fit.  Good luck.
Reply:I agree with Aaron, maybe tap the hole up a size and use a larger shorter bolt if you can.www.urkafarms.com
Reply:Originally posted by Newb Thanks Aaron, this is into cast iron (about 50 year old).  You mean 50% of the bolt diameter not 150% right?
Reply:For a bolt that small, EDM really is likely to be the best option.Another thought: I haven't done this in a long time, but if you have access to the back side where the bolt hole is, and can grind enough of a flat on the CI to spot a small drill (maybe 1/8") roughly in line with the center of the bolt, drill in to the bottom of the hole from the blind side, heat the CI around the hole SLIGHTLY to try to grow it (may 50 degrees above ambient) drill into the bottom of the bolt with a RH drill and see if it will grab the stub and spin it out. I'v done this in Aluminum, but if you arn't DEAD on line, and near center, it can make a real mess. Also Al grows MUCH more than CI relative to the steel bolt. The hole needed to be liquid tight, so it got filled with putty.Hey, just thought of something... If you can get in from the bottom end this way, you may be able to drill into the bolt enough to knock the extractor out with a pin punch....  Never tried going that far.I wouldn't try sticking a rod to the top of the bolt except as a last resort. You might be able to get a hold of the easyout and pull it free, or it might weld in to the bolt tighter. Very likely to blast the cast iron threads-- not much room to get a sleeve in for protection. With the extractor in there, you probably won't be able to turn the bolt stub, due to spread by the wedging action. If you can get the extractor loose with a welding rod or EDM, the bolt will likely take enough heat to turn out rather easily by sticking another rod into the top of it (the heat will loosen it a tad, and the shrinking weld metal will loosen it more) The hole in the bolt will tend to protect the CI around it.
Reply:You might try a 1/8" - 5/32" cobalt bit using a 1/4" OD (nominal) sleeve of some sort as a drill bushing to keep it centered.  That way, you should be able to remove most of the broken Easy-Out.  Then try a bit of heat (MAPP, O/A) around the hole to expand the cast iron slightly and then use the left hand bit trick previously mentioned to back out the broken screw.It sounds like the casting threads must have had some rust, causing the old bolt to fail.  Suggest chasing the threads with a 1/4" tap (1/4"-20 most likely) before installing a new bolt.
Reply:It's so bad now, I'd probably get pissed and blow the bolt out with O/A, and then helicoil the hole or retap it 5/16, since my free EDM source ran dry.Make a NOTE: next time break a bigger bolt, they are easier to work on.Appreciation Gains You Recognition-
Reply:One of the mechanics at a local golf course swears by this method.  I couldn't find another link very quickly.  I know there are other brands of electrodes to do this with.  http://www.messer-welding.com/MgS600new.htm