OK so I did my best, but I must be missing something. I think it has to do with the internal threads not pulling the hub down straight onto the taper. I am getting 3 thousandths runout mid-hub, 7 thou at the end of the hub (ack!) and 3 thou on the face. Interestingly I have a CF spinner backplate that is so uneven the prop tracks perfectly

I re-indicated the hub and all the parts are concentric to within 1 thou, so the thing is simply sitting cock-eyed on the crankshaft, I think.

I would really like some advice on how a real machinist makes threaded parts that align properly when screwed together. I lathe-threaded the prop shaft and bored the corresponding hole before tapping it (using an aligned tailstock and a good chuck). I used a Four-jaw chuck, indicated everything fanatically before each step, etc and when I screwed the stainless shaft into the hub it had so much wobble it was almost funny. I ended up threading a new piece of hex stock, screwed it into the hub and machined the other end with the shaft in the hub. I thought I was such a genius for carefully facing the mating surface and leaving a gap between the threads and the surface etc...

This my first attempt at machining anything, and I have learned a lot, but to say that I am discouraged is an understatement. I have a new appreciation for how complex a simple-looking item can be. My father-in-law thinks I'm being too picky and that if the prop is tracking OK it's alright, but I don't agree. I think I'll give BME a call tomorrow and see if they'll sell me one of their adapters. Ineed to get on with my life.

Suggestions welcome.

KD