[A Quiet Boom]

Actually it's a standard black oxide coated bit in a Black and Decker keyless (worthless) chuck drill motor. A lefthand bit is won't work because the tool is drilling out the core of the stud leaving only the threads behind. We started out trying to weld nuts onto one of the studs and heating it cherry red but it just broke off. It was quicker and easier to just drill them. I brought along a second tool body with a bushing large enough for a bit for time cert taps but didn't need it since all of threads came out rather easily. The fifth picture down shows the threads spiralling out of the hole. I apologize for the poor photo quality, my digicam is broke and I had to use my camera phone.