[TheForge] Re: drill bit stuck; the final solution :-)

[Keporter at aol.com]

In a message dated 6/1/2005 4:54:48 P.M. Pacific Standard Time,  
sunironworks at yahoo.com writes:

Oh, this  is a manifold off an old military truck, not the kind of thing
I want to  wreck and have to replace. Goes without saying I  suppose.






The best answer for you now is to have the stud removed by  EDM. If you can't 
find anyone with an EDM device set up for stud  removal, and if you feel 
brave, then:
 
Use 5/32" carbon rods in a miniature carbon arc torch, built from a drilled  
out # 4 cutting tip (I think); or was it larger? You can check the  sizes when 
you by the rod and tip at a welding supply store). Cut the back  end off the 
tip, run pipe thread on it and cross cut it, so that a female  nut will cause 
it to tighten around the carbon rod. Drill and tap a hole in its  side for an 
air pipe (which also gets clamped in the welding stinger). Put  an air fitting 
on the other end of the pipe.
 
I don't remember the recommended amperage of this carbon size, but it isn't  
much (less than 75 amps as I remember), and use a 60 PSI air source  (anything 
higher just blows the end off the carbon). The mini carbon arc will  probably 
take you half a day to construct, but Aircar's clumsy version cost four  
bills thirty years ago, and wasn't anywhere near as good as what you  can make 
yourself. The multiple holes around the carbon allow very  clean gouging to be 
done, and fortunately for you, carbon is not  compatible with aluminum. Steel 
and aluminum don't like each other very  much either. With a little patience, 
you can remove your problem very  cleanly, and you get to keep the "eraser" for 
the next nasty job.
 
We used to use them at Boing Boing (Boeing) to get our tails out of a  crack 
every time some engineer made a booboo. Every welder had one in  his toolbox 
for self defense. They are so precise, you could do a sculpture with  one.
Mike P.