In my shop I have plenty of NEMA 6-20Rs (240-volt, 20-amp receptacles) and not enough NEMA 5-20Rs (120-volt 20-amp receptacles). These are all right next to the panel.
My goal or my desire: I want to run a 20-foot 10/3 power cord to a two duplex box attached to a work table to run simple motors and perhaps a work light. I want one duplex outlet to be on one 120-volt leg of the 240/20 and the other duplex outlet on the other leg.
Question: Can I use the neutral as a ground or should I use 10/4 for a separate ground?