Abstract: In a self-propelled combine, crop material is gathered from a field and transferred by a chain and slat-type feeder house to a fore-and-aft disposed axial flow rotary separator including, from the front, infeed, threshing and separating portions respectively. The infeed portion of the rotor is in the form of a helical conveyor having an outside diameter of approximately equal to that of the threshing and separating portions of the rotor. The chain and slat conveyor of the feeder house, which is considerably wider than the outside diameter of the separator rotor, is arranged to deliver undershot fashion to he underside of the infeed rotor.