Did you try rotating the "scooping" tube without the screw being there? It would seem that just the tube would force product into the bottom and its only path to escape, is up. Sorry, I didn't find this 'til today.,(reply>), I believe the screw is taking some of the weight of the 'scooped' material, so it can be lifted higher before the weight of the accumulated stuff is more than the 'pressure' of new stuff getting scooped. So, it's not absolutely necessary in all applications, but it makes it more efficient in most cases.