Abstract: A feed cup mechanism, of the type generally used in grain drills, includes interchangeable feed wheels of various seed metering circumferential surfaces, of various tooth sizes or surface irregularities, and of various thicknesses. Interchangeable spacers of various thicknesses and of various peripheral sizes complement respective ones of the feed wheels to provide a metering passage having a suitable radial thickness for a particular type of seed and having a suitable width for metering a suitable quantity of seed. A pivoted seal is provided which cooperates with the various sizes of the feed wheels and with complementary ones of the spacers to prevent seed from passing from a receiving opening to a discharge spout except through the metering passage. Optionally, the pivoted seal is oscillated to agitate the incoming seed and thereby to provide more uniform metering of the seed.BACKGROUND OF THE INVENTION1.