Upper and Lower Feed Rolls grip the wood to ensure a positive feed rate. This coupled with variable speed allows the operator to change particle size from a sawdust product to a biomass chip for outside furnaces. The SC-12 and the SC-18 Slab Chippers are sawdust producing machines designed to fit into a sawmill operation. It will process your slabs as they come off the mill into either Sawdust for livestock bedding or biomass material for outside chip burners, simply by changing the rate of feed. The top half of the SC-18 opens with a hydraulic lift system for easy access to the chip blades.