quattroworld

worked great for a couple, sadly in the end the head had to come out because of one that was just down low and too tough to get in situ.

accordingly, here's another tip: if the stud is broken off just ABOVE the face, (and assuming not enough and/or you can't take a welded-nut approach) you can use the nub that is left as a centering peg for a jig. get a nice thick chunk of steel plate, and using a true drill press, drill a small pilot hole all the way through. then drill a tiny pocket from one side exactly the OD of the fastener just deep enough for the fastener nub. you can then fit the plate over the nub, and using the small pilot hole, progressively drill the fastener out knowing you are dead-centered.

one mistake however I have also made is jumping too far in size while drilling. if you get too ambitious with drill bit jumps, the drill will be more apt to ignore the previous pilot hole and wander off center.

to make the centering more accurate I have also seen more elaborate jigs with a hunk of channel or angle tacked on above the plate so that the effective guide length doubles or triples, but you need not only room for that jig but also long enough drill bits to accomodate.