From: Buzz (muttman@charter.net)
Date: Thu Nov 17 2005 - 21:26:00 PST
Listers,
On Thu, 17 Nov 2005 13:31:35 -0600, you wrote:
To remove broken bolts on old equipment I assume that the bolt is rusted and
that's why it broke. Especially head bolts, or studs, that go into the water
jacket. I don't like using heat because that plays havoc with the temper of the
metal. I've never had much luck welding on nuts because I couldn't get the
proper penetration. Speaking of penetration, penetrating oil will break the
surface rust bond, but after a week it only penetrated a few threads. If I can
get the bolt or nut to move a little then I add more penetrating oil and work it
in and out a little at a time until it comes off.
Back to the original problem.... get the drill. If the part is broken off below
the surface I use the proper size transfer punch to punch it exactly in the
center, then follow up with a regular center punch. I usually start with a
center drill, then a SHARP 1/8" drill. I use enough force to remove material but
not so much that I bend the drill. If too much force is used the drill will
bend and go off center.
I then start using left hand drills 1/16" at a time, up to just below the tap
hole size. If the piece is still in the threads then I tap the hole. Usually
what happens is that as I approach the size of the broken piece it'll spin out
of the hole.
Forget about eze-outs they just break, then your in REAL trouble. The only time
that I've had good results with eze-outs is if the bolt was new and broke from
over tightening, or was sheared off. If I use eze-outs I like the square ones.
The left hand threaded ones seem to swell the bolt then it is tighter.
Buzz
BTW buy a GOOD set of drills because if you come up against a class 8 bolt
you're gonna need a good drill.
>
>What would you do when you have one like the one being discussed that is
>broken off up in the threaded hole?
>
>Sonny
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