I thought that radial and American ball thread were the same thread. One was just made by a particular company and the other is the generic name for it. (Like Advil vs Ibuprofen). Is that not correct?
Same, same, but different is my experience. I've used American Ball pins that fits perfect with a stock Radial thread, but I have also ran into pins that had a slightly bigger minor, about .315" instead of the Radial spec .312"
Usually it's not a problem, but it sucks to run into stuff like that if I' m making a shaft or rethreading a shaft for a customer and don't have the actual cue the shaft is for in my hand. This has happened a few times and it's been a Jacoby every time.