The smaller the angle between the blade and stone, the sharper the knife will be, but the less side force is needed to bend the edge over or chip it off. The angle between the blade and the stone is the edge angle – the angle from the vertical to one of the knife edges, and equals the angle at which the blade is held. The total angle from one side to the other is called the included angle – on a symmetric double-ground edge (a wedge shape), the angle from one edge to the other is thus twice the edge angle. Typical edge angles are about 20° (making the included angle 40° on a double-ground edge).[1] The edge angle for very sharp knives can be as little as 10 degrees (for a 20° included angle). Knives that require a tough edge (such as those that chop) may sharpen at 25° or more.
In terms of feedback, in the eyes, and in the hands of many sharpeners, the feedback on this particular brand of stones is not to their liking and often it is enough to stop them from using them. These are thinner than other stones as well so you may get the impression that you are not getting your moneys worth. They are very hard stones, there is no soft, creamy sensation as you sharpen, there is not much feedback at all in fact.

Both Belgian Blue and Vielsalm Coticule are ancient stone layers found in the Belgian Ardenne Mountains with characteristics similar to both Novaculite and Siliciclastic sedimentary stone in that it is a metamorphic stone consisting of both gray and yellow volcanic ash mixed with tiny Spessartite Garnet crystals suspended in a clay matrix. However, due to its geology, both types of stone occur only in vertical seams sandwiched between two thick layers of bluish-purple slate and thus, they must be meticulously extracted mostly by hand. However, this type of extraction process is both very time-consuming and very labor-intensive and, quarrymen can only extract the stone for a few months each year due to inclement weather conditions. Consequently, both Belgium Blue and Coticule whetstones tend to be somewhat expensive.
The smaller the angle between the blade and stone, the sharper the knife will be, but the less side force is needed to bend the edge over or chip it off. The angle between the blade and the stone is the edge angle – the angle from the vertical to one of the knife edges, and equals the angle at which the blade is held. The total angle from one side to the other is called the included angle – on a symmetric double-ground edge (a wedge shape), the angle from one edge to the other is thus twice the edge angle. Typical edge angles are about 20° (making the included angle 40° on a double-ground edge).[1] The edge angle for very sharp knives can be as little as 10 degrees (for a 20° included angle). Knives that require a tough edge (such as those that chop) may sharpen at 25° or more.
This was the first Whetstone that I've ever purchased. After reviewing several 'how-to' videos, I jumped right in to use it. I found the process nearly meditative and the BearMoo stone extremely effective! The first knife I sharpened was very dull with small, jagged edges. The 1000 grit side effectively removed the jagged indentations and created a nice cutting edge. The 4000 grit side made the knife razor sharp. The process took nearly 40-minutes.
The sharpener has come a long way in the past couple of thousand years and yet it hasn’t. That is, while there have been incredible advances in the development of mechanical knife sharpeners the classic and very ancient sharpening stone is still with us and very much in use as you read this. The best knife sharpener for you will be one that meets the needs of your cuisine and your temperament but which, first and foremost, reliably produces the sharp knives (look after your knife!) you need with the least hassle.
Visually, a very sharp knife has an edge that is too small to see with the eye; it may even be hard or impossible to focus in a microscope. The shape near the edge can be highlighted by rotating the knife and watching changes in reflection. Nicks and rolled edges can also be seen, as the rolled edge provides a reflective surface, while a properly straightened edge will be invisible when viewed head-on.

Aluminum-Oxide oil stones are very popular man-made sharpening stones produced by an abrasives company called Norton and which are commonly called India Stones. Generally less expensive than Arkansas stones (aka Novaculite), these stones are graded coarse, medium, and fine and are designed for fast cutting. Yet, when the fine grit is used, they can also produce a relatively fine edge. Also, because India Oil Stones are both softer and coarser than Arkansas Stones, they are commonly used in conjunction with Novaculite to cut the initial edge bevels or, repair extremely dull or damaged edges before refining and polishing the bevel with an Arkansas Stone.


Cutting angle – With a manual stick or sharpening stone you set the angle yourself so this does not factor into the equation when choosing that type of sharpener. When shopping for an electric sharpener however it does. You’ll want to decide if you want your knives to have the 15 degree “Asian” style angle so that you can make precise cuts or the Western standard 20 degrees or 22-degree sharpening angle. Most people will opt for the 20 or 22-degree angle simply because their cuisine doesn’t call for a lot of finesse from their knives and those knives are probably of a heavier Western variety anyway.
These are very popular stones. 8" Dia-Sharps have a single grit per stone making them more expensive, but at 8" by 3" they are wider than the 8" DuoSharps, offering a good working surface. The 8" Dia-Sharp line also has the widest range of grits available from DMT, with extra extra coarse, medium extra fine and extra extra fine options not available in other sizes, so it is good line to consider. One coarse and one fine stone is a good starting point.
Removing the burr is fairly simple. You'll need a leather strop or block (this sort of thing), which is designed to catch the metal fibres from the knife. You could do it with a fibrous tea towel or some newspaper if you like, but I'd suggest going with leather to begin with. The motion is fairly similar to sharpening. Draw the knife over the leather, going away from the edge at roughly the same angle as when you sharpened. 
Removing the burr is fairly simple. You'll need a leather strop or block (this sort of thing), which is designed to catch the metal fibres from the knife. You could do it with a fibrous tea towel or some newspaper if you like, but I'd suggest going with leather to begin with. The motion is fairly similar to sharpening. Draw the knife over the leather, going away from the edge at roughly the same angle as when you sharpened. 
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