When I need nut of a particular size, my instinct is to buy one, not make one. Thrifty Bill, I didn't want to believe you were right, but it looks like you were. Internet searching turns up zip, nada--I would have thought that these binder bolts with the undersized nuts would surely be available somewhere. I mean, they were mass produced not that long ago, right? And it's not like they could have been all that rare--I think other Miyata-built bikes, like Univegas, used them, too. Dang it! I'm not entirely confident that I can precisely file a small fraction of a mm off all six faces of a hex nut while maintaining the original geometry, but I guess it's come to that.