I have a tool that I bought when I had a motorcycle that works pretty good on stuck bolts or screws. You postion it on the offending screw, give it a slight twist to the left, then hit it with a hammer. The hit keeps the bit in the screw and gives it a slight turn to the left. Sometimes it takes a few strikes to get it out, and the head of the screw must be able to hold the bit, so I have to be sure to use it before I have stripped it out. Do not remember what it is called, but it works.
Lee
