Having a spare set of Shopsmith Replacement Planer Knives ensures that you keep working in the event of your Planer blades become dull or nicked over time. Our Replacement Planer Knife Set includes three hardened steel knives, each precision-ground to exacting specifications. The finely-honed cutting edge of the blade is made of hardened M-2 steel fused with a low-carbon steel base for durability. This special process ensures the ideal combination of edge-holding ability and strength, without being brittle. The blades are then treated with a special rust preventative solution for lasting performance. We recommend you always have a spare set of knives on-hand to keep down-time to a minimum. Includes: Set of (3) Replacement Planer Knives. Set your Planer Knives Quickly, Easily and Accurately with the handy Shopsmith Planer Knife Setting Gauge (513414).