RC Premium Diamond Sharpening Stone

I recommend and use 300 / 1000 grit, double-sided, diamond stones as an essential part of my tool sharpening method.  Our diamond stones use only high quality mono-crystalline man-made industrial diamonds permanently adhered by electroplating to a thick, precision milled, steel substrate.  Use the 300 side for flattening your water / ceramic sharpening stones and the 1000 side to establish your secondary bevel or your initial flattening grit. We quality control test EVERY diamond stone we receive to determine if it's flatness is within our standard of being out of flat, either convex or concave, by no more than .004 (4 thousandths) of an inch.  Stones outside our standards are rejected. Diamond stones within our standards are further graded as "Standard" or "Premium" quality. The difference between our standard and the premium version diamond stones is the level of flatness.  Diamond stones that test between .0016 and .004 (1.6 to 4 thousandths of an inch) out of perfectly flat, are gr