Chris Kantarjiev [mailto:cak@dimebank.com] wrote:
>
> Check out http://bosphorus.dimebank.com/tech/BrokenBolt.html for
> a long disccussion of "tried and sometimes true" techniques...
I don't think I'd pay much attention to the above "suggestions". He
seems to recommend using EZ-Outs a lot - even going to the
recommendation of using an impact wrench with EZ-Outs!!
In my experience, EZ-Outs tend to break with the slightest bit of
excess force (I can't even imagine using an impact on them) as they
are very strong, yet very brittle.
I've had luck drilling out broken (and rusted) studs in a cast
iron exhaust manifold - basically, the cast iron tended to be harder
than the steel studs, and it tended to "guide" the drill into the
center even when drilled slightly off center. I started with a
small drill and progressively drilled larger holes until I was at
the drill size for taping the proper size stud. At that point, I
ran the tap into the hole, and it pretty much followed the
original threads in the case iron - simply chipped out what was
left of the stud's original threads.
My other case was the removal of a broken (and corroded) bolt
from an aluminum head. The EZ-Out broke in the hole. Had to
remove the head and take it to a machine shop. They managed
to weld a nut (thru the center of the nut) to the remains of
the stud (in spite of the broken EZ-Out), and the broken bolt
came out easily.
Avoid EZ-Outs. I've yet had one work except when I broke the
bolt while installing it (over tightening it). Any corrosion
and they will just not work and will just make things worse...
Tim Mullen
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