... not break, chip, crack, hollow or groove. -Very easy to use, no oil required. 6" Diamond Whetstonemainly used for sharpening metal & woodworking tools ... break, chip, crack, hollow or groove. -Very easy to use, no oil required.Blue – Coarse #180/#240Quickly restores a dull edge to ... desire cutting fast action without worry of edge refinement often use our coarse models. Color code: coarse (180 or 240 ...