Bought my first dressing tool. Both wheels on bench grinder had deep grooves in them. The dressing disc wore down to round washers in first use but still working. I decided to make my own disc from 1/4" steel plate, slugs produced from iron worker. Used 1 1/4" punch , drilled 1/4" hole through concave side made by punching plate. Grind down the convex side of washer making it possible for to install 2 washers in dressing tool. Works better and longer than original tool.