I started with 269oz steppers driving stainless steel threaded rods and after wearing out a couple on the z axis started looking for CHEAP alternatives I have replaced all threaded rods with OLD DISCARDED SATELLITE ACTUATOR acme threaded rods.
After tearing the actuators down and cleaning the threads they work wonderful and the price was perfect. A satellite repair place gave me 10 old ones for free. you get about 24 plus inches of usable acme threads and finding several of the same brand was a snap.