Abstract: A rotary grinder for sharpening mulcher blades. A grinding wheel is rotatably mounted atop a work support surface. A platform removably mounted to the work support surface includes a first upwardly facing blade supporting surface and a second upwardly facing blade support surface. The second blade supporting surface is obliquely arranged relative to the first blade supporting surface. The first blade supporting surface contacts the outer portion of the blade positioning the outer edge against the grinding wheel. The method includes moving the blade in a direction so that the outer edge of the blade moves past the grinding wheel with the blade moving off of the first upwardly facing blade supporting surface and onto the second upwardly facing blade supporting surface thereby positioning the obliquely arranged second cutting edge adjacent and against the grinding wheel.