All I can suggest is to do your best to get the drill centered, that was always the most difficult for me. Don't use the spiral ez-outs as when you break one of them in the hole it takes a carbide bit to drill it out, they expand and lock the broken part, don't ask me how I know. I've had fair success with the tapered square ones, drive as deep as possible then clamp a vise grip on it and using a lady finger, wiggle and pry it out then tap it back in lightly so not to expand the broken part and try turning it out. soaking with penetrating oil or diesel fuel if you can could help also but I'm sure you know that, (caught myself rambling) Good luck. H.