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Asymmetric vs Convex?

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jgraeff

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So im debating on whether or not AS ground knives are better for releasing food than a convex grind.

Or is a AS with a Convex grind even better?

Anyone have any input on this?
 

Benuser

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The AS are asymmetric: left side flat, right side convex. Left side very small bevel, straight; right side large convex bevel. If the right side were flat one should expect wedging.
 

heirkb

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He's not referring to Hiromoto AS. He's using AS as an abbreviation for asymmetric.
 

NO ChoP!

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I think when one says convex grind it conjures the thought of the entire knife face, where as a convex bevel, which is what you're talking about, obviously denotes the bevel only....
 

Marko Tsourkan

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The way I understand asymmetric grind (different from asymmetrically sharpened), is to have one side ground at one angle and the other side at another (higher angle on a cutting side), as opposed to a symmetric grind, where both sides are ground at the same angle. Asymmetric grind offsets the edge line from the center (on a symmetric grind) to left or right, depending on whether it is for right or left hand user.

For instance, Watanabe branded knives are ground asymmetric. For a right handed use, left side is ground at lower angle and right at slightly higher angle. Both sides are convex ground from 1/3 down approximately, though left side has a shallower convex and appears to be flat to a naked eye. However, if you put a straight edge to each side, you will see that they are convex ground.

Whether asymmetric grind has an edge :) over symmetric, I don't know. I am curious about it myself.

M
 

David Metzger

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This asymmetric grind idea has me very excited! Thanks Marko for the info on the Watanabe. Yeah, asymmetry is not about whether it is convex. Some Japanese knives are concave on the left side like Usuba and Yanagi-ba I believe.

I am curious if the Japanese maker wants the edge in the center or to the left on a gyuto?

Marko, Dave Martell and the other premier knife makers - On your knives are you going for the assymetry or not? I will have to try both to see which I like better.
 

Pensacola Tiger

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Just to illustrate what Marko is saying, here's a shot of a Watanabe Pro 24 cm wa-gyuto:



Rick
 

tk59

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Food release depends on how well the food can contact the surface of the knife. It depends on a lot of things including the kind and size of the food you are cutting. Anything that deviates from a polished, flat surface will work. The further from the polish and the flat, the better. With regard to edges, the larger the bevel the more it contributes to the overall shape of the face of the blade. Asymmetry allows for thinner geometries. There is not black and white answer to your question. The answer is food, technique and "trade-off" dependent.
 

jgraeff

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Tk- good response and I do agree that all those factors come into play.

I'm wondering if you had the same profile knife ground several different ways lets say both flat with 50/50, one with asymmetric grind but 50/50 bevel, asymmetric grind with AS bevel, a convex ground with 50/50, and another convex ground asymmetric bevel an used it in the same food which would be better overall. I know it hypothetical just curious as to which would perform better.
 

David Metzger

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Thanks tiger and 59, That's a great photo showing the grind! The edge is really to the one side quite a bit. The expertise, craftsmanship and creativeness of the Japanese Knives are amazing. tk59, Thanks for your insight, it makes a lot of sense.
 

tk59

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Tk- good response and I do agree that all those factors come into play.

I'm wondering if you had the same profile knife ground several different ways lets say both flat with 50/50, one with asymmetric grind but 50/50 bevel, asymmetric grind with AS bevel, a convex ground with 50/50, and another convex ground asymmetric bevel an used it in the same food which would be better overall. I know it hypothetical just curious as to which would perform better.
If we are talking strictly about food release on a nice-cutting knife (thin behind the edge), flat will be worst regardless of edge unless the bevel is very large. Asymmetric, not flat grind with asymmetric, large bevel will be best, in most cases.
 

jgraeff

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Interesting thanks for the info TK! As far as sharpening asymmertric bevels, what's your method? I normally do about 60% on the right side at about 10-15 degree and about 40% on the back at about 18.

Is this correct? My edge doesn't look like that watanabe though wish they did :)
 

olpappy

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Kanetsugu from JCK are both asymmetric and convex. They cut superbly...
 

tk59

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Kanetsugu from JCK are both asymmetric and convex. They cut superbly...
A lot of Japanese knives are, maybe even most of them. My Rottman knives are also asymmetrically ground.
 

jgraeff

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This knife would be far from my first choice. Just saying.It looks almost barbaric.

He mailed this one in.
What don't you like about the grind salty? Seems like its done pretty well am I wrong?

Also how do asymmetric edges compare to symmetric edges in terms of edge retention?
 

Salty dog

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Forgive me for lack of lingo, from this perspective the food facing side shows some finesse albeit bold. The back side is all over the place but has the right idea.

We won't talk about that choil.
 

tk59

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...Also how do asymmetric edges compare to symmetric edges in terms of edge retention?
Should be the same. The only disadvantages are some "steering" which is really only a problem (I actually like it this way.) in extreme cases like the Watanabe shown and there isn't quite as much metal behind the edge so they don't work as well for hammering, lol.
 

Salty dog

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If you're used to a typical 50/50 ish this knife will take some getting used to.
 
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