Grind Finishes

Whether or not a manufacturer makes a convex grind, a high flat grind with v-grind secondary, or a hollow grind they generally all have the following two flaws. First, they are generally not sharp enough for my tastes. Second, the finish is usually very rough and “toothy” which is another attribute I do not like for the way I use knives. There are of course exceptions to this, even from high volume production knife makers (it is not hard to find out who they are). I am speaking in general terms here, and in more cases than not, the above statements will be true.

I used to buy a knife and think “well, the manufacturer must know better than I do and there is no way I could improve upon what they have done.” Boy was I wrong. The more I played with my own edges, and the more I am exposed to manufacturing processes and capabilities at work it all makes sense.

Most knife making companies can not afford to spend a whole lot of time refining the edge they chose for their knife. The reason they chose a particular edge will be discussed more in my Favorite Grinds article. The point being, once the edge geometry is chosen, it is usually refined a certain amount based on manufacturing capabilities, and then things stop there.

It is very rare for me to get a new knife and NOT immediately run it to my belt sander. If I do not like the final grind geometry, I will actually re-grind it a bit. That will take care of the first issue above; not being sharp enough. Keep in mind, you don’t want to really get into doing that unless you understand a little bit about different steels, and what their capabilities SHOULD be. Even if I do like the edge geometry, I will still generally polish the edge using two different leather belts, and two different grades of polishing compounds. That will take care of the second issue above; too rough of a final finish. Why is this important to me?

A toothy edge acts kind of like mini-serrations. They work well for doing things like cutting rope and activities like that where you cut with a slicing motion. However, for most of the stuff that I do, durability and push cutting is more important. When the final edge has a very high polish on it, those mini-serrations are refined until they are very, very small. A highly refined surface like this is more capable of cutting it with a pushing motion. The high polish on the edge also makes it more durable. If you take the “toothy” edge for example, and over-exaggerate it, it will look like a saw blade, with big teeth. If you take that and try to chop a log (like you would with an ax), what would you expect to happen. Probably a tooth or two will end up bent and mangled. See my point? Now try to do that with an ax, and you should see no edge damage. Well, the same concept works on a microscopic level. The difference being that on the “toothy” edge, you will probably not see the damage to the teeth, instead you will just know that your edge is dull.

The more punishment that an edge takes, the higher polished it should be. This almost seems counter-intuitive, but it is true. For that reason, all my axes have a mirror like finish on them. It took me quite a while to learn this. I used to sharpen my hand ax with a file and maybe a coarse stone, and figure “hey….it’s an ax…..that is good enough.” After all, it is just going to get beat on, right? Well, since I learned better, my hand ax goes through all the polishing stages and I have noticed great improvements of the performance.