It's fun and informative to read your posts, George. :-)

If I accurately picture the device you are describing, we made something vaguely similar in the boat ship, to work with wood -- far easier of course. We took a roll pin, and filed crude teeth on its circumference. After trying every other method to remove broken screw shanks from planking, we would pop this disposable tool in a drill, and drill around the offending shank. Rotating counter-clockwise (left-handed, lefty-loosey), it would often grab the shank and extract it. (Still had to deal with the now-larger hole in the plank.)