"John" wrote in message
...
I'm trying to determine which of the acids we used to use, in the old
days,
to disintegrate broken taps or drills. I remember when that was done
occasionally, but don't remember which acid was used. I have a friend who
has a broken drill in cast iron and I thought this might be a possibility
before we start chopping at it with carbide tools and make matters worse.
It
might at least loosen it up enough to remove by hand. It's a 1/8" dia.
drill
and not in too deep, about 3/16", but it's bound pretty tight.

Thanks
John
=----

One trick I have used in the past with quite good results is an arc
welder. Put a sleeve down the hole to protect the sides, use a
piece of mild steel with the welder set on fairly low current. Stick
the "electrode" down the sleeve until it "sticks" to the whatever you
are trying to get out. Turn the welder off - you now have an extension
on the whatever it is stuck in the hole. Actually works fairly well
many times.

mikey