Uneven Bevels and Asymmetrical Grinds and What They Do

We’ve had a lot of conversation and threads posted on this misunderstood and often confused subject.  This Forum is considered a place to post questions and find answers to our questions on how to use our Wicked Edge Precision Sharpeners, (WEPS).  It also is a place to share information on how to utilize and maximize our WEPS to sharpen a variety of grinds applied to knives.

Usually when we speak of “uneven bevels” what first comes to one’s mind is when we look at our knives we noticed our bevel height from one side of the knife to the other doesn’t match.  Aesthetically the knife doesn’t appear even.  This is a constant battle and a source of difficulty to the new WEPS users and anyone trying to sharpen their knives so they “look good”.  The question “why do I have” or “how do I fix” my uneven bevels is posted at least a few times a year, as new users, getting through the “learning curve” with their WEPS notice the bevel height difference from side to side and seek help to correct and avoid it. This issue was always a non-issue in the past. Probably something we most certainly never noticed or at least didn’t really care about.

Now that we’re able to apply our own self-directed precision grind to our knives we’re sharpening, it becomes a real a source pride. Even sized bevels ground and polished at an accurate precise angle, of our choice, becomes our reason for why we bought this fancy expensive vice. The ability to do it repeatedly is the cherry-on-top!

There is a different kind of “Uneven Bevels” or “Asymmetrical Grinds’ that is done intentionally. Actually, there are many of these, that have a function and serve a real purpose.

http://www.africanxmag.com/Knifesharp%20Edge%20Types.jpg

Recently I purchase several new chef’s knives that made for right or for left handed users. The grind is different from side to side, and done the opposite way, depending on which hand you hold your knife. These knives are called 70/30 grind. That, in itself, raises the question “what does it mean”.

I have some of these style knives already in my collection. When I sharpened those knives I followed WEPS protocol and techniques and used my sharpie to match the bevels and just went with it. I decided I wanted to get the right answer on what angle to sharpen them to. I took my question outside our Forum, as is sometimes necessary, to find a different body of experience. I posted my question to the “Kitchen Knife Forum” looking for help to sharpen my new knives.

Jon Broida of Japanese Knife Imports gave me permission to share his posted reply:

Sharpening angles are one of the most common things I am asked about. I find it’s often important to talk about them together with asymmetry, but let me address the sharpening angles first. In general, there is not going to be an exact angle that is correct, but rather a range of angles that works. For instance, most double bevel Japanese knives will work well with angles somewhere between 10-15 degrees per side. The closer you are to the 10-degree side of things, the sharper the knife will feel, but it will also be more fragile, brittle, and may not hold its edge as long. The closer you are to the 15-degree side of things, the more tough and durable the knife will be, though it won’t feel quite as sharp. It’s also ok to go even lower or higher than this, depending on your personal preference, though I often recommend staying within this range until you have a better understanding of how things work for you. For what its worth, Japanese craftsmen aren’t measuring the angles when they make or sharpen the knives either. Lastly, it’s important to keep in mind that you don’t have to always use the exact same angle. If you want your knife to feel a bit sharper, go a bit lower. If you need a more tough and durable edge, go a bit higher.

As for asymmetry, it seems that this is a rather confusing issue for many. Part of the confusion stems from the fact that many of the ways that we describe these asymmetries are gross oversimplifications. For example, the ratios like 50/50 or 60/40 don’t really describe anything of substance. Is it the ratio of the percentage of sharpening on each side? Is it a ratio of the angles on each side? In reality, it’s neither. No craftsman in Japan it’s there and measures angles or ratios. What really matters is the way that the knife cuts. The asymmetry deals with two main issues-thinness behind the edge and steering. The more asymmetrical a knife is, assuming the angles are equal, the thinner the knife is behind the edge. However, the more asymmetrical the knife is, the more likely it is to steer. It’s also important to keep in mind that the angles are not always equal. When figuring out asymmetry for any given knife, the first thing that you want to do is cut with the knife. When you cut with a knife, you want to assess whether it is steering to the right or to the left, and how easily it moves through the food. If you notice that your knife is steering to one direction or the other, you want to create more surface area on the side that it is steering towards, so that the knife cuts straight. This can be done by adjusting the angle (either more or less acute) and/or adjusting the amount of time spent sharpening on each side. If you notice that the knife is wedging in food as it goes through, this may mean that you need to sharpen at a more acute angle, or that you need to thin behind the edge. Some of this can also be dealt with through adjusting asymmetry, as previously mentioned. Does that make sense?

Another Forum senior member shared this link which I’ll share here.

I hope this is helpful and interesting to our Wicked Edge Forum.  It provided the insight and answers I was looking for.

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