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Removing Broken Bolts

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  • Orrin
    replied
    "I have over the years blown out literally hundreds of broken studs in cast iron manifolds using a acet/oxy torch, sometimes sacrificing the first couple of threads (sometimes not)"

    Now that is impressive to me! Maybe all the rest of you are good with an o/a torch but i've only used one, maybe 10 times. I can't manage those awsome smooth cuts and delicate stuff you all can. I think thats really cool!
    The oxy-acetylene approach is my preferred method when the stud is obviously stuck, solidly.

    The less drastic tricks should be used first, such as left-hand drill, slotting with a Dremel cut-off wheel, etc.

    The trick to the oxy-acetylene method is to work fast. If the stud is stuck in cast-iron, speed isn't quite so important. In steel, work fast in order to keep the base material from reaching ignition temperature.

    I've never tried burning a stud out of aluminum. IMHO, the risk of failure is too high. In such a case I'll drill the stud considerably under-sized, then carefully open up the hold with a carbide burr to the point where the threads are visible all the way around.

    At that point the remainder of the stud can be picked out with a scribe.

    Regards,

    Orrin

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  • pkastagehand
    replied
    slightly off topic

    Originally posted by Ken_Shea
    I have over the years blown out literally hundreds of broken studs in cast iron manifolds using a acet/oxy torch, sometimes sacrificing the first couple of threads (sometimes not) but after that they are ok.
    There is learned technique to it but it is easily done.
    I've used a similar technique on exhaust systems to get the stub from a muffler or pipe out of the inside of another pipe. In this case putting the heat of the flame along the length of the pipe. The rust/corrosion between pipes is somewhat of an insulator and if done right keeps the outer piece from getting hot enough to melt.

    I suspect there is some of that happening with the steel studs in the casting. I imagine the back spatter in your face must be something though...

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  • Timleech
    replied
    Anyone tried the Loctite freeze spray for this job? I've used it to help with shrink fitting shaft couplings in situ, never used it for its intended purpose.

    Tim

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  • jmm360
    replied
    If you're using an EZ out you're already having a bad day. Don't make it worse by breaking off the ez out. Left handed drills are great, I hear the welding on a nut trick is great, but I say stop and take a breather. Not long ago I broke the heads off 2 of 3 bolts removing an air brake pedal. After removing the treadle I soaked the bolts with PB blaster, the repair got put on the back burner. When I got back to it 2 months later, one tap of the hammer on each and I unscrewed the broken bolts with only my fingers, the boss and my coworkers still don't believe me but it's the truth.

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  • Marv Frankel
    replied
    Forgot the easiest method!!!

    Guys,
    I forgot to mention the easiest method for removing broken bolts or even broken taps. One of the other members of our Southern California Home Shop Machinists, lives about 2 miles from me. He has the cutest little homemade EDM machine, that will cut holes through nearly anything. When it's finished cutting, the sides of the broken piece, which are nearly disintegrated, are easily removed with a pick.

    Marv Frankel

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  • Marv Frankel
    replied
    Slightly different method

    Guys,
    A lot of years ago, I found that EZ-Outs were pretty much useless. Primarily, because they screw into the drilled hole, and continue to apply pressure as you try to unscrew the broken part. I've been far more successfuly making my own tools, by grinding a long, slim square taper on the appropriate size toolbit, and driving it into the drilled hole. This almost broaches a square into the hole. Then, clamp a tap wrench on the toolbit, and carefully unscrew the broken part. Some kind of penetrant doesn't hurt the process. Back in the "old days", I used to use Carbon Tetrachloride, from a hand held fire extinguisher, but I think that's been banned.
    I've even used the above method to remove broken spark plugs from aircraft engines, as far back as about 1950.

    Marv Frankel
    Los Angeles

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  • Guest's Avatar
    Guest replied
    There you are, AK, they need you on the Chinese bike thread!

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  • A.K. Boomer
    replied
    The V/6 nissan pathfinder has a design flaw in its exaust manifolds -- they like to pop there rear studs, there is no room for drilling so i take my high rpm air powered little disc saw and cut a regular head slot in the broken stud and then i can spin them out with a shorty regular screw driver, sometimes i have to get into the head material but what are ya gonna do u know....

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  • pcarpenter
    replied
    By design, an e-z out tends to expand the bolt in its hole...which does seem counter productive. My uncle showed me some broken bolt removal devices he had that came from Rigid as I recall. It was a better design, but pretty expensive.

    I have had amazing success using the "weld a nut to the bolt" technique that has been discussed at length here. I believe it even showed up in one of the magazines onece. It worked like a charm the two times I have had a chance to use it since learning of it.

    It is successful for two reasons. The first is that you have a great handle on the piece of remaining bolt when you are done. The second, and perhaps more important issue when the bolt broke due to being frozen in place is that it heats and cools the bolt, helping to break the bond. It also potentially shrinks the portion of the bolt that ends up near the weld. This technique has been mentioned here for removing failed ball bearing races from blind bores...you weld around the perimeter of the outer race and when it cools, it shrinks.

    Of course, the welded nut technique begs for a wire feed welder as it makes it much easier to reach down through the hole when dealing with smaller nuts.

    Paul

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  • Guest's Avatar
    Guest replied
    Prefer left-hand bits, but hang on to the ez-outs.

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  • wierdscience
    replied
    Easy-outs area contradiction in terms,the meaning is the reverse.If the bolt will come out easy they will work(almost able to catch with a fingernail and spinout).I do hundreds of broken bolts a year and never use easy-outs.Most times if it's loose enough for an easy-out to work a Dremel and a carbide burr will mill a slot in the bolt for a screwdriver that will do the same job with no chance of it snapping off in the hole.

    I weld out nearly 95% of the bolts I see.Over the years the methods I use have evolved.I used to use washers,but ditched that for angle iron clips.

    You can punch a hole in one leg of an angle clip to fit the bolt,place the clip on top and weld through the clip to the bolt,this protects the machined surface from spatter and leaves a handy tab sticking up for a cresent wrench or vise-grips to latch onto.In addition it allows for more mass which retains more heat which soaks into the bolt and increases the effect.

    You want the bolt to expand in the hole and transfer that heat to the surrounding metal.The bolt will be the first part to cool which allows clearence in the thread interface.

    Thread clearence or the lack there of account for the 5% I drill.Bolts that have been cross threaded,bolts that are rotten and cooked into a hole and selftapping bolts have no clearence to speak of and as a result the play on expansion does nothing to aid removing them.These will be drilled and insert repaired anyway so I don't bother trying to weld them out.

    I have welded out bolts broken off an inch or better below the surface of the part,but that is a different method all together and I am tired.

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  • Fasttrack
    replied
    "Easy outs are only good if the bolt is able to be threaded out by hand and is not frozen in place. Of course, if that were the case then the damn thing wouldn't have broken in the first place."

    That what i have found as well - personally i like using those e-z lock thread inserts. Especially for applications for my trans pan bolts where i was working under a car and trying to drill in the center of a grade five bolt with an uneven surface and a crumby center punch mark thats surrounded by aluminum...well lets just say i certainly wasn't good enough to be able to manage that!! With a square piece of steel and square holes drilled in it, i drilled the bolt hole oversize, threaded it and inserted the ez-lok and its worked great since! I understand this isn't an acceptable solution in many situations, but if you can, it really worked great. Took alot less time than trying to drill the center and then pound it out (which i've done to a varying degree of succes on exhaust manifolds )


    "I have over the years blown out literally hundreds of broken studs in cast iron manifolds using a acet/oxy torch, sometimes sacrificing the first couple of threads (sometimes not)"

    Now that is impressive to me! Maybe all the rest of you are good with an o/a torch but i've only used one, maybe 10 times. I can't manage those awsome smooth cuts and delicate stuff you all can. I think thats really cool!

    Leave a comment:


  • garyphansen
    replied
    How much do I have to sent you to get you to send me your easy outs? I have had good luck with them when ever I used them. Gary P. Hansen

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  • Ken_Shea
    replied
    I have over the years blown out literally hundreds of broken studs in cast iron manifolds using a acet/oxy torch, sometimes sacrificing the first couple of threads (sometimes not) but after that they are ok.
    There is learned technique to it but it is easily done.

    Lots of oxy, 60-80 lbs.

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  • A.K. Boomer
    replied
    Its easy to do the "uncoil" if the part can fit on your mill but a hand held drill and its difficult, most easyouts are junk, i really dont like the reverse spiral ones because they spread the bolt out and make things worse, iv had a little luck with those straight splined ones though, you drill to a certain size and then they kind of broach in --- they dont spread the stud like the others and will work most times if the hole is drilled pretty much to the center...

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