The vast majority of desktop 3D printers in use today use one or more lead screws for the Z-axis. Sometimes you need to think outside of the box to make an improvement on something. Sometimes you ...
In order to upgrade his Prusa i3, [Daniel] designed and printed his own z-axis carriages to use with the lead screw. If you have a Prusa i3 too, he’s uploaded the design files to Thingiverse.