Understanding Grit: You’ll see a bunch of numbers being thrown around when discussing the grit of a sharpening stone. The number refers to the size of the grit. The larger the number, the finer the grit. A good beginner stone would be a two-sided stone with #400 and #1000 grit. The #400 grit is the courser stone for working out the nicks and imperfections, the #1000 grit is for refining.
The truth is that there is no one recommendation that we can make that will meet everyone’s needs. Every sharpener’s needs are different and every sharpening toolkit will be different. In order to help beginning sharpeners get started with good sharpening stones to build around, we need to understand their individual needs. So with that in mind, let’s look at the basic needs of a beginning sharpener.
The speed and polishing ability of waterstones attract many sharpeners. Waterstones sharpen quickly and are available in fine polishing grits not found in other stone types. The ability to flatten the stones is a necessity when sharpening with waterstones, so a starting set should include a flattening stone of some kind. Our article, How to Flatten a Waterstone, has more information about keeping waterstones flat.
Low Grit Stones: A sharpening stone with grit number less than a 1000 is generally used for knives and tools that are damaged. If your blade has any nicks or chips in the blade, the stones will take care of them in a jiffy! They usually have a coarse side for nicks and chips, with the other side for general sharpening. Even if the knife’s edge has become totally blunt, the stone will re-sharpen it perfectly.
We tend to recommend natural Japanese water stones only to experienced users who are thoroughly familiar with the synthetic Japanese sharpening stones. Natural stones are not to everybody’s taste and there are inevitably many uncertainties with regard to their grit grade, which cannot be determined exactly, their hardness and their suitability for certain types of steel.
In addition, the most prized of the natural Japanese Water Stones are quarried in the Narutaki District north of Kyoto, Japan and are commonly available as either bench stones or pocket stones in grits ranging from 120 to 12,000. On the other hand, synthetic water stones are made from Aluminum Oxide and commonly available as either bench stones or pocket stones as well in grits ranging from 220 to 8,000 and, although this is the same abrasive material used to make India Oil Stones, the difference between the two is that the binder that holds the abrasive together enables Water Stones to be much softer than India Oil Stones which, in turn, promotes faster cutting because the worn abrasive material breaks away more quickly and is replaced with fresh, sharp, abrasive material more quickly. In addition, because water stones do not become glazed or loaded with swarf like oil stones can, new abrasive particles are constantly exposed as the stone wears so it continues to cut consistently. Plus, they can be lubricated effectively with water (rather than oil which can ruin some water stones) which combines with the fine particles of abrasive from the surface of the stone to form a slurry which polishes the bevel as the stone cuts. However, it should also be noted that Water Stones do become uneven significantly faster than other types of whetstones although, their softness does make them easier to true again.