A friend gave me this shaft to try out and to sell. It's quick release Predator type. Would anyone know what the thread would be. I don't own a Predator cue. It's piloted and 31" and shaft is new. Maybe a 5/16x14 butt would work? Guessing it should be worth $150.
No, a 5/16x14 butt will not work. You need a butt with a Uniloc pin to fit it. You also need to be careful because OK Healing also sells a slightly different pin that looks like a Uniloc, but isn't quite the same, and only fits their own off-branded Uniloc style butts.
I've seen these on Aliexpress. They're ~$70 - $100 brand new from the manufacturer (OK Healing). They come in a variety of lengths between 690mm (27") and 788mm (31"), and in a variety of joints, and a variety of tip diameters, and in both conical and pro taper. You'd be hard pressed to sell it for the same cost as a new one, let alone for more.