Ah. I thought they were for bending! Threw away all those drill bits. I didn't even hold it very hard. I finished the job with "hard metal" drills tips.
The trick for almost big enough holes is to run the bit anti-clockwise...........it works well, I didn't believe it but it has worked well in the past. I didn't need to do it on any of the BB parts except the camera mount where the print was very rough and needed a lot of clockwise work too.
