Another option (if the stub-shaft is real hard and can't be threaded easily) is to cut it off, grind a small flat, and use a wheel collar (with set-screw) instead of the traditional nut to retain the prop. Did that for many years... due to custom strut lengths. Additionally, if you're brave, just cut it off, and put a snug piece of tubing behind it... nothing else... I also did that for years... just don't drive like a fool... LOL!