Knife Grinds Explained

This first diagram shows a few of the more popular knife grinds.

Scandi

The scandi grind is about as simple as there is to understand. In the world of primary and secondary grinds, things and terminology can get confusing real quick. A scandi grind is simple, because there is only one grind, and you are looking at it. It is typically in the range of 12.5 degrees per side, or 25 degrees inclusive. With this being the only grind on the blade, the bevel created is wide and flat.

This grind is typically recommended for beginning bushcrafters because the width of the grind makes it very easy to sharpen. Other thinner grinds can make it harder to determine what the proper sharpening angle is. With the scandi grind, being wide, you can just lay it down, pivot the knife on to the grind, and it becomes obvious that you are holding it at the correct sharpening angle.
This is just my opinion that will continue to pop up multiple places on this site; if you don’t know how to sharpen your knife you have no business using it or carrying it. If you are out in the woods with a dull compound bevel knife and do not have the knowledge to do anything about it, you are in trouble. That is the reason the scandi grind is usually so highly recommended.

While we are on this grind, I want to comment on two more points. One of the most popular and disturbing recommendations that I come across is putting a secondary grind on a knife like this. The recommendation usually goes like this “You can just run it across the Spyderco Sharpmaker (which is 20 degrees per side) and put a secondary bevel on it.” This recommendation just makes me cringe! The WHOLE POINT of the scandi grind is to avoid a secondary grind. If you want a secondary grind, you are much better off going with a different grind all together, like a high flat grind.

Second is the idea of the edge becoming convex with time. Many knife makers claim that over time the scandi grind will become convex through many sharpening sessions. I have no information to support that, but I also have no reason to doubt that the edge will become slightly convex in time. The problem is that I believe that the edge would only become mildly convex and would be very hard to tell with your eye alone. In order to prove that statement, I believe you would need precise measuring instruments. Either way, the point does change a thing for me in terms of the type of grind. I am all about end results in real use.

Hollow

The hollow grind as shown has a concave profile for the main grind. Every hollow ground knife that I have seen has a secondary bevel on it, which is typically a v-grind. The hollow grind is one of the weakest grind types due to less metal being present. The grind is supposed to be good for skinning purposed. I personally do not use them, so I can not comment on them much more than that.

Full Convex

This grind is very much the opposite of the hollow grind. There is no real apparent bevel on this grind. As shown in the diagram, the blade profile is convex with continuous curvature from the spine to the edge. There is no flat area of the blade as with other grinds. The diagram helps to show this.

High Flat

This type of grind is pretty self explanatory and shown in the diagram. The main grind is flat, and ends closer to the spine are of the knife. Where things can get confusing with this type of grind (and a full flat grind) is the secondary bevel. It can be a v-grind, a convex grind, or a compound grind (which is multiple angles of a v-grind closely simulating a convex grind).

People tend to get confused because someone will say that they put a “convex edge” on their knife. It often gets interpreted as a full convex (referenced earlier). Obviously, putting a full convex edge on a high flat ground knife would be very difficult. What they are usually talking about is the secondary bevel has been put on with a convex profile. To see more about doing this, and how to do it, please visit the sharpening area of this website.

Full Flat

Very similar to a high flat grind with the exception that the flat grind goes all the way to the top of the spine. As shown in the diagram, there is no flat section of blade near the spine. The flat grind is a single line from the knife spine down to the secondary bevel. The secondary bevel (similar to the high flat grind) can be a v-grind, convex, or compound also.