From: uniquemachine@air1.net
Date: Tue Sep 24 2002 - 13:38:51 PDT
I have gotten out a fair # of broken bolts/screws/ taps/extractors by
the same method using a mig welder. you just have to be careful.
Jon
>
> >A- A way to get a broken easy out - out of the engine block
>
> You can try any or all of the following. I have done all of these at one
> point or another, not all may be applicable.
>
> Place a nut over the stud and fill in the hole with a welder being sure to
> penetrate into the stud, I have only ever done this with TIG, can't vouch
> for other welding methods. Apply liberal amount of Kroil, several
> applications even, before doing this, and after. Often times the combination
> of Kroil and heat with the little bit of force you can generate with the nut
> is enough.
>
> Heat the stud with a TIG torch, which has very concentrated and high heat,
> and maintain it red/orange for ??? I don't know, 10 seconds or so perhaps.
> This will heat up the surounding metal but no where near what a gas torch
> would, yet the high temp imparted to the stud may be enough to break any
> rust bond. Carefull tapping with suitable chisels/punches tools may allow
> you to unthread it.
>
> Using various chisels, my personal favorite being a round nose cape chisel,
> eat away at the stud till you can expose some of the extractor. Using
> various chisel and punch type tools you may be able to loosen the extractor
> in the hole and get it out or even pulverise it. Be prepaired to ruin the
> points on most of the tools, you'll have to do some resharpening. You also
> may damage some of the thread in the block but that should not be a problem
> as there should be plenty left to maintain full strength, but something to
> at least be aware or.
>
> Drill out the stud and perhaps some or all of the thread in the block with a
> hollow drill, sort of looks like a hole saw but more precise. I've only
> bought one or two of these, don't know what they are actually called or
> where to get them, seems to me they are intended for machine tools as
> opposed to a hand drill as you cannot use a center drill even if it had one.
> This will require you to make a guide block out of steel (most likely) that
> the cutter just fits into, this block gets clamped using whatever is
> available such that you keep it centered over the stud/hole. You may be
> able to drill only the stud, depends on how large the extractor was, or you
> may end up removing the entire thread from the block, in that case you will
> have to install a thread insert, the solid type normally. Lots of variables
> with this method but it may work here, maybe not.
>
> Just a few random thoughts, hope it helps,
>
> good luck,
>
> je
>
>
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