... It makes so much sense. The weight of whatever is being lifted isn't baring down on what's being rotated. If it was a standard type of auger, the weight of the sand would be pushing down on the screw making it harder and harder to turn. With the casing rotating, the screw can be a structural part. It could be made to support that weight which is easy cause it can remain stationary.,(reply>), @Stephen Willard To quote some of you origonal comment: "With the casing rotating, the screw can be a structural part. It could be made to support that weight which is easy cause it can remain stationary".  But still has to be housed within the outer tube, and as I commented somewhere below, the Olds arrangement should (simplistically) half the rotational forces on the inner flight, unless some traditional long flight augers power the inner flight from both ends, which they well might?<br> But other than that it does not matter if the outer tube is rotated or the inner flight, the mechanism moving the material and the forces so induced remain exactly the same. Regards, Marcus,(reply>), @Marcus Gault So you think I'm saying the weight of the material being lifted isn't bearing down on the flights of the Old's elevator? I'm just trying to clarify what you think I'm saying.,(reply>), @Stephen Willard Stephen, it is clear that since the rotating outer tube, through friction, drags the material around the inner helical "auger", and thus forcing it to rise up the endless incline, this same, equal and opposite force must therefore be transmitted "down" onto the inner auger, whether the inner flight or auger is stationary or  rotating makes nary the bit of difference. The weight, or mass of the entire column of material being moved must be supported, and is still mostly supported by the inner auger or flight. If the inner auger flight were disconnected from the outer tube, and both were free to move  freely and vertically, while either were rotated, the outer tube would rise against the inner flight, or the inner flight would fall relative to the outer tube. Simple mechanics at work, from my limited farm based and traditional using auger experience 40 to 50 year ago. I also studied Civil Engineering at Uni, dropping out in final year.<br>But I kinda understand simple mechanics, simply put, there are no free lunches.,(reply>), @Marcus Gault I really don't understand where you think I'm making a logical fallacy. What do you think I'm saying in my original comment? Like, I know what I'm trying to say but it obviously not communicating the same message to you. Can you explain where I'm wrong?,(reply>), @Stephen Willard Perhaps I shall demonstrate by posting a video, where I lift myself by my bootlaces, being the same same logical fallacy, well kinda.