A non-row sensitive corn threshing header (15) comprising a forwardly disposed cutting apparatus (19) for severing standing corn crop from the ground and a rearwardly disposed threshing apparatus for separating kernels from the plant, collecting the kernels, and discarding the remaining plant. The threshing apparatus includes a plurality of screw auger conveyors (30, 40) arranged in upper and lower planes that receive the crop and urge the crop into diminishing space between adjacent auger conveyors (30, 40), the space defined by the auger flighting (34, 44) and the expandingly tapered auger shanks (32, 42). Kernels are separated from the cob as the ears are urged rearwardly in the threshing apparatus. The header (15) may include screens and the like for cleaning the grain of chaff prior to transferring to on-board storage or chaff removal may occur after the grain is off-loaded from the harvester.