Flatness is the key to sharpening. In order to make a sharpening stone flat that isn’t, you need something flat and abrasive. Several companies make flattening stones, and we’ve heard concrete driveways are pretty flat, but we’ve always used a DMT® stone because we know it is pretty flat. However, it is hard on them, and they don’t last long. DMT® heard our pleas and created the Dia-Flat™ Lapping Plate. The Dia-Flat™ is designed to flatten all oilstones and waterstones. Flat to +/-0.0005 and coated with the revolutionary DMT® Diamond Hardcoat Technology™, the aggressive diamond coating makes short work of not only flattening any conventional oilstone or waterstone, but with a lighter touch, and is also the go-to tool for maintaining your as well.