…or maybe even in their home machine shop. (I’m certain I fixed that once. How did it sneak back in?)
To be honest, I’ve no freakin’ clue. I’ve got a copy of The Henry Ford Shop Manual and it says that their taper is the easiest to measure, which is absurd, since all tapers are calculated using the same formula, and are made the same way (with minor adjustments to the compound to get the correct ratio), plus, it’s pretty rare that you’re going to need to make a live center, since they’re fairly cheap to buy. I can’t even imagine that it works as a preventative measure against theft because it’s easy to make an adapter.