Lathe spindle drive

This is a stepper drive on a Delta wood lathe. The lathe was retrofitted with a router which requires much lower torque compared to normal wood turning.

The lathe spindle has a 1" - 8 threads per inch and MT2. So the work is held from the MT2 while the spindle is driven from the outside threads.

I'm posting two possible solutions. a single pulley with threads and a pulley with a separate nut. I was concerned that with threaded pulley would loosen and designed the nut & pulley combination.