That’s brilliant...  does it actually need the screw to be all the way up the lift?,(reply>), Good question! Probably it does not need the screw all the way to the top. In order to function it would obviously need high friction on the sides, and low friction on the screw. The whole device works on a balance between the frictional forces imparted by the sides of the cylinder, against the weight of particles and fiction on the surface of the screw.,(reply>), I suspect it would take more force to crank it if the screw stopped short of the top?