Lead screw for DIY lathe ??

[Dogtemple]

ok cool, if you're going the plastic route, you may want to consider PTFE or high density polyethylene, they're about the lowest friction plastics you can get and easy to work with. you could get a lump of it and cut your own thread to go with a length of good quality threaded rod, thats what I would do any ways. if you wanted to just do a test, most plastic chopping boards are made from polyethylene.

for the friction on pulleys, check this video out at around the 5.30 mark - https://www.youtube.com/watch?v=iSLmzjE_woQ

[Naboo]

I'm not quite setup to do that kind of thing myself, would love a metal lathe.. maybe one day soon

Those Igus products are either stainless or hardened alloy lead screws, with composite self-lubricating plastics for the nuts, sounds like they'd be super smooth and quiet.
Maybe similar stuff to delrin, or whatever the T-560 uses

Sweet cheers, will give it a watch