1. hollow grinding
The hollow grinding or concave cut is is really very sharp, but the blade is weakened, it is very thin. Razor blades are sharpened with that grind, but also some "alround knifes" where the focus is on the cutting.
Regarding razor blades it is important that they are really aharp and thin. A hollow grinded blade can by no means used for chopping or cutting under high pressure.
The hollow grind is mostly used for cutting tools and weapons.
However, the blade is weakened and has a lower stability with this kind of cut. This form of the carving represents a geometry of cutting that has come into existence by grinding.
This cut may be a year. Because of this special way of sharpening the blade get thinner and thinner. This cut gives a high sharpness, but, as already mentioned decreases the stability of the blade. Moreover, this is not as robust. Therefore, the hollow ground is used to cut soft material.
There are 08/15-Sharpening tools like those mostly seen in kitchens or where cooking knifes can be sharpened. These devices mostly have two "rolls" (rotating or still) where the blade can be drawn in a 90° angle. This creates a new sharp edge very fast. But this sharpness creates a kind of " hollowing out" and the edge is very thin and frgile. In most cases this does not make sense for knifes used in the kitchen. When you use it normal the edge will break and you have to sharpen it again very fast, because it is vulnerable for breaking.
2. spherical grinding (spherical cut)
The crowned cut (convex edge) is also known as "Eisenhauer cut" (comming from special swords of the medieval times) or "Solingen cut". It looks like two arcs coming together. The benefits of this cut is a quite good sharpness together with a good stability of the cutting edge. This cut can be found in many of these kitchen knives (European knifes). The biggest advantage is the stability and durabilty of the edge .
A clear advantage of this type of cut is that the blades after a blow in solid materials ( wood, bone ) can not jam or jam so easily.
This is due to the initially quite sharp angle in the vicinity of the cutting edge. A little later the materialis getting thicker, which contributes to the robustness of the edge. As I said, the spherical ground does not led to an outstanding sharpness, but offers a very high stability of the cutting edge. Is very suitable for chopping tools, such as an ax.
However, a spherical section can also occur unintentionally due to an improper grinding of the blade.
3. surface grinding
This is the simplest form of cut . Stable than the hollow ground but not quite as sharp. The surface grind is a good compromise between the edge of the hollow grinding and the stability of the spherical grinding.
Knife with this finish, they have a unique sharpness. The sharpness of the blades is given by the fact that they lie flat on a stone and then sharpened on each side. In this process, a slight oblique procedure should be performed on the stone.
It is relatively easy to resharpen blades with this cut .
4. single sided grinding
The single-sided-cut can be found by most of the Japanese knives and a plurality of tool cutters used . it gives a very strong blade and is very easy to regrind. The grinding angle varies depending on the application . In America, it is also called "Chisel Grind" . Through this cut results in a sharp and quite stable cutting.
