For anyone interested, the main flaw is that I threaded the inside of the shaft piece much further than necessary because I couldn't figure out why the Point piece wasn't seating completely. It's been a while since I've done tap and die threading, and this two piece thing is a new idea, as well. I forgot about the need to cut a thread relief in the female threads to make up for the way the die doesn't quite cut threads all the way to the bottom of the (Male) thread tenon.
Bottom line is I drilled and threaded the tap hole far deeper than necessary and that made me chary about cutting too much of a curved shape in the shaft piece. I'll need to make a new shaft piece at some point. Everything else is good though.