Abstract: In a grader device grain is fed down a slide which ejects the grain outwardly and forwardly into an airstream. The slide is provided by a resilient flexible sheet, the contour and inclination of which is adjusted by a plurality of support rods against which the sheet presses and the positions of which are adjustable. A plurality of transverse collecting troughs with adjustable baffles, receive the separated grains according to the weight thereof with the top quality grain being heaviest, collecting in the forward trough. A suction fan extracts dust before it reaches the main airstream and diverts it into a cyclone or the like. Accurate airstream control is achieved by a plurality of adjustable wind boards strategically situated within the grader device.