Shop Tip #318
© Frank Ford 2006; Photo by FF

Sharpening stones wear unevenly as you use them. Oil stones also develop a glazed surface that makes them far less efficient.  The classic method for breaking that glaze and flattening the stones is to rub them on a scrap of plate glass sprinkled with silicon carbide grit.  Water stones can be lubricated with water or left dry, while oil stones should be lubricated with kerosene during this process.  I like to use 80 grit silicon carbide for this job, and if I run out of loose grit, I'll substitute the coarsest silicon grit sanding sheets I can find.