I have had one of these for years and have NEVER failed to remove a stud when using it. The only caveat to that statement (there is ALWAYS a caveat) is that you need to get reasonably close to where the stud enters the casting (or whatever) otherwise you will simply twist the stud until it shears.
Of course do the usual heat thing first and remember that this device will probably destroy your screw/bolt thread, but it would certainly get a screw out of a lambretta hub.
Unfortunately I can't remember where I got mine, but it has no brand on it, so I doubt it was anything of reasonable reputation. I think it only cost me £10 to £20, but it has been invaluable.
I'm not on commission!
