Diamond stones can sharpen fast and, depending on the grain size, very sharp. This DMT DiaSharp Bench Stone is a good size for all kinds of knives, including large kitchen knives. A major advantage of grinding on a diamond stone is that it does not have to be laid out flat. The DiaSharp stone is mounted on a thick steel plate of 9 mm thick. As a result it stays flat.
Information about grain size DMT sharpening stones
The grain size of a diamond stone and a whetstone are not necessarily comparable, because the materials and the way they are produced are completely different. A whetstone has the abrasive grains processed inside in the stone. During sharpening these granules break loose from the stone and form a slurry. A diamond stone has the diamonds stuck in surface of the stone itself.
Important to know
The DMT stones allow you to choose between dry or wet sharpening. Wet sharpening has the advantage that the stone remains lubricated and excess material is drained. Use only water and never oil. It is also good to know that a diamond sharpening needs a couple of sharpening sessions before it sharpens at its best. A new stone can be a bit too coarse at the beginning. After sharpening 5 to 10 the stone is at its best and final.