Randy, I'm DAMN jealous of your CNC capabilities -- I've done mine with the low-tech hammer-and-anvil techniques, working off the bearing outer diameter and the existing planes and bolt holes... it is precise enough to work, but everything hinges off the initial assumptions, as opposed to pulling the centers off the mill display, with equal precision and no cascading dependencies.

I oversimplified above -- as Randy noted, there's some mojo in making the stickout depth of the input shaft, retainer, pilot, clutch, and etc... and the clutch linkage and throws all have to be worked out, as well, but those were pretty easy, compared to getting the shafts in line and in axis.

Randii (also a Randy, BTW)