The Deulen Tools planer and jointer knife sharpeners are precision engineered designed to accurately sharpen and hone the blades used in woodworking planers and jointers. Planers and jointers are essential woodworking tools that use rotating helical or straight blades to smoothly flatten, straighten, and trim lumber as it passes over the cutterhead. Over time and use, these blades naturally become dull and nicked, decreasing the quality of the cuts and finish they produce. Sharpening them is critical for maintaining optimal performance.