The easiest way to keep your planer knives in good condition without removing them from the machine. The diamond hone consists of two diamond slips, 325 and 600 mesh, held at an angle in a wooden handle for topping and backing the blade. Applying the diamond to the edge of the blade and moving it along the length with a uniform pressure should restore the blades to their former glory. Please note, these are for honing the blades, they will not restore chipped or very dull blades. See online video. Suitable for HSS or TCT edged blades.