It’s incredible that for centuries after Archimedes created his screw, no one thought of the reverse until this guy..<br><br>Round of applause for him,(reply>), @nicolorau Sort of like some 3D printers.,(reply>), @simmojosh I'm sure it was, more than likely it wasn't known by other people or was just forgotten about.,(reply>), You mean milennia.,(reply>), @Ennar The screw is under almost as much stress.  The torque applied to the product by friction is trying the make the product spin, and that spinning torque is transferred to the screw.  The screw also takes all of the vertical force placed by the moving product.,(reply>), not centuries my friend, MILLENIA.