loose hay or the like is delivered into a progressively narrowing axial space between two rows of identical teeth which project towards each other from side locations on a pair of obliquely related wheels . the hay or other material is simultaneously compressed and advanced by the teeth as they come together . the teeth form axial boundaries for pockets or chambers in which the hay or other material is compressed into blocks . the radial boundaries of such pockets or chambers are formed by an annular outer wall carried by one of the wheels and an annular inner wall carried by the other wheel . one of the wheels is mounted for rotation in a fixed position . the other wheel is mounted for rotation by mounting means which can be shifted in position for the purpose of varying the axial space between the two wheels , for adjustment of the pocket size .