Originally Posted by
3alarmer
...just so you know before you start, if the drill bit gets locked in there and the bolt as a unit starts spinning, there's no way to hold it steady after you've drilled out the hexagonal socket in the top bolt portion. Which is an excellent reason not to do it that way.
And after you've spun that nut a few times, it will have polished/enlarged the hole in the crankset and your replacement nut is unlikely to lock itself into place. (I love cranksets where the nut seats simply tightening the bolt. Need to get it out? Back off the bolt slightly and give it a gentle tap with a hammer.)