A screening apparatus (10) for screening particulate material includes a frame (12) having an open bottom (14) through which screened particles can pass and a plurality of banks of blades (16A 16E) supported on the frame (12). Each bank of blades (16) is rotatable about respect axes of rotation (18A 18E). The blades (20) of each bank (16) are evenly spaced and arranged in a single row coincident with their respective axes of rotation (18). At least one of the banks of blades (16) is able to slide linearly along its respective axis of rotation (18) to provide a predetermined amount of axial freeplay. When the blades (20) agitate rotated and a particulate material is placed in screen frame (12), the rotating blades (20) agitate and/or crush the material to allow particles of a size equal to or smaller than a gap formed between each of the adjacent blades to fall through the open bottom.
