[Espeefan]

Screw drives are great. Nice and reliable. Easy to build. Best of all (maybe) no hydraulic leaks! But the one thing I noticed about the screw drives is that the speed at which they raise a dump box is not linear. They lift or lower really fast torwards the bottom of their travel, but then slow down at the middle to top of the lift travel. Not much you can about that, except maybe do a sissors type lift?