I watched a young guy a few years ago struggle to get 6 broken flush grade eight bolts drilled to use an extractor. This was the wing hold down bolts for the sidewings which are famous for breaking off......usually flush or just below flush. He screwed around for over an hour trying to drill one bolt, and after pretty much giving up, came over to me and asked what he should do. I was in the middle of another project so I told him to take a break (which is going to the local convenience store) and I would look at it when he got back. As soon as he left, I took my die grinder with a cutoff wheel , centered the wheel over a different broken bolt...........pushed it into the bolt about 1/4 inch and backed it out with a screwdriver. I removed all of the other 5 broken bolts in less than 5 minutes but left the one he was working on. When he returned, he couldn't believe that I had got the other bolts out so quick and asked what I did. I showed him exactly how to do that with the following statement..........." Son, you have to think outside the box in this business." Before he left the business less than a year ago........He told me that he had learned more working around me than he had ever with anyone else. Too bad he left, he was a great kid that could have gone a long ways in this business with the right lead.