"dpb" wrote in message ...
DoN. Nichols wrote:
On 2007-12-30, Oren wrote:
On Sun, 30 Dec 2007 16:18:19 -0500, wrote:
Any tool for extraction will work but it's the setup that counts.
[ ... ]
1. If broken bolt is above surface grab it with vise grips, use a
engraving tool to buzz it out, or turn it with a sharp punch.
[ ... ]
Good post. I've never heard of the engraving tool trick.
By "buzz it out", do you mean the vibration helps the bolt to turn
easier?
This is (I think) the kind of engraving tool which has a carbide
point in an adjustable vibrator Something like a "Burgess Vibro-Graver".
You place the point on an area away from the center of the broken bolt,
but not too close to the threads, and angle it so is is driving both
down into the bolt and CCW. This is likely to get the bolt out --
though to be honest, I've never tried it.
In that case, what's the point of the vise grips?
This suggestion needs more explanation to make any sense to me -- if the
bolt is so bound as to have caused it to twist off in place, seems
unlikely this is going to work -- although I've no such engraving tool,
either.
I'm the heat cycle kinda' guy, meself... 
I do like the idea of the tack-weld a new nut on -- now if I only had a
MIG or wire-feed unit instead of (or in addition to) the stick...
Sometimes a bolt head will shear off because of sideways forces, and not be
in the threads hard. Sometimes there is not enough sticking up to get a
vise grip on there. I have had several that once you got it turned a couple
of turns with an ice pick, you could get it the rest of the way out with
your fingers.
They're all different.
Steve