I sharpen my knife and plates on a large wetstone I have. Coarse on one side fine on the other, have never had to use the coarse side. I have a old comercial 220 volt grinder with several plates and do around 20 deer and 5 or 6 hogs a year. My uncle used to take the plates to the shop he worked at and had them run on a table grinder to flaten them out, that worked great .