i've done that in my research. You break a stud off in a $20,000 vacuum
pump... so you tig weld a stud or nut to the remainder of the stud to be
able to grasp it to back-it-out.  Very common.
matthew

John Rodgers wrote:
>
> sanford schulwolf wrote:
>
> > I was working in my friends shop last week - he is a
> > top vw syncro guy in SF and saw him working on the
> > exact problem.  What he did ( stay with me as I don't
> > know all of the proper terms) was cut a tubular piece
> > of some type of Metal , on one side he welded a lage
> > bold head.  Next he cut a 4mm (about) section out of
> > the tube- length wise, through, about a 1/4 of the
> > tube. (whole tube was seated from the base of the
> > broken stud to the original length)  ........  He then
> > welded this tube to the broken stud and simply
> > unscrewed it.
\\