I’ve been using this #10-24 (~5mm) leadscrew for almost a month now, and it’s been working flawlessly. The coupling is just zip ties on vinyl tubing. No slippage at all due to the reduced friction of the tiny nut vs an 8mm nut. Thin leadscrew + flexible coupling = no leadscrew wobble (aka z-wobble) + less friction = lower torque (and current) requirements on z-motors. The threads are a finer pitch (24 threads/in) than 5/16″ screws, which are usually 18 threads/in, so the resolution is better, too.