General Specifications for NRG COMPANY, INCORPORATED Screw Conveyors Part 2 - Products 2.1 Shafting   End shafts shall be drilled for coupling bolts and fitted for a key on the drive side. All shafts shall turn in the bearings mounted on the side walls. Split, cast iron set collars shall be attached to the shafts with stainless steel hardware and held in place by stainless steel set screws to keep the shafts in proper alignment.