@DavidR8
I'm a little late to the party.
I think I might make it as follows:
Put the stock in a your lathe chuck with about 3" stick-out.
Turn the OD and blade-side face/counterbore.
Drill and bore arbor hole to precision fit. My washer is a very close fit. When removing, if cocked at all, it binds. That's a good thing.
Part off at finished length.
Turn a spud on the stock with OD precision fit to washer ID.
Face the stock to mate with saw-side of washer (mounted on the spud).
Drill and tap the spud for 1/4-20 or 28 retaining screw.
Mount workpiece on spud and retain with a flat washer and a button head (hex socket) cap screw.
Turn conical feature to suit. If the flat washer gets in the way, cut it too.
Take some pictures of finished part and post them.
EDIT: Make 3 or 4 more and sell them on eBay for less than the competition.