Some notes for asymmetric angles

[Leo Barr]

I think the reason most quality Japanese knives for cooking are asymmetric is firstly the harder steels will support lower angles so this allows for very low angles that will give a sharper edge the steep angle on the opposite side is to give strength to the edge .
These blades may well have a centreline that is not vertical but trails off to the left or right depending whether it is for a left or right handed user.
If these knives are not sharpened correctly they will not track properly when cutting. It should be understood that in general these knives are more specific in their applications and been made of harder steels they are unsuitable to sloppy wham bam use.
Certain edc knives may benefit from asymmetric edges say for feather sticking to dressing meat in the field. virtuovice prepares many of his Bark River knives in this way refer to his you tube channel .
Asymmetric knives come from the obvious such as a Yanagi or a Deba whereas Guyutous or other knives may range from 60/40-80/20 in short when sharpening unknown Japanese knives they require careful inspection as most except the pop knives like Shun / Global / Mac are not symmetrical.

[Leo Barr]

A double bevelled knife parts the flesh even like a wedge a single or say asymmetric knife applies pressure more to one side the side which is not held this does considerable less pressure damage to the food both raw fish or food like fruit is not bruised resulting in less cell damage therefore a better flavour crushed celsl rot quickly which will not be pleasant with sashimi and even an apple hacked with a blunt knife or bruised with a broad double bevel knife will discolour more rapidly.

[Zamfir]

So, I can see for a sushi restaurant where they have a big piece of fish, and they are cutting off pieces for a serving and saving the rest for later. I am guessing for a right handed person the bevel would be on the left or the wider bevel? If a chisel grind, the only bevel on the left when holding the knife. This would then cause the damage to the piece being cut off and eaten quickly and it preserves the larger piece from extra cell damage? Is this what you are talking about?

A double bevelled knife parts the flesh even like a wedge a single or say asymmetric knife applies pressure more to one side the side which is not held this does considerable less pressure damage to the food both raw fish or food like fruit is not bruised resulting in less cell damage therefore a better flavour crushed celsl rot quickly which will not be pleasant with sashimi and even an apple hacked with a blunt knife or bruised with a broad double bevel knife will discolour more rapidly.

[Leo Barr]

The bevel with the wide bevel is on the right side as you look down from the spine for a right handed person so this half wedge pushes on the part of the fish or fruit or whatever is not been held so there is minimum pressure damage since it is purely pushing it away from the main body as it is liberated by the cut hence minimal damage since the flat or concave side is exerting very little pressure3 on the main body which is held.
The less the food is damaged the better the flavour even if the food is then cooked.
A piece of steak cut with such a knife prior to cooking will hold in the flavour much more than a damaged slice of steak.This is why there are left and right sided single bevel knives for left or right handed people the slopped side is always on the opposite side to the main body of that which is been sliced.

[Zamfir]

That makes sense. Interesting. Thanks!

[Steven N. Bolin]

In line for sharpening is a Korin Misono UX10. The specs for this particular knife on Korin’s website states it’s a 70/30 bevel.

I thought I’d post a few more awesome diagrams I just found online before I get started… If you’re interested 🙂

source: google images “70/30 bevel sharpening”

Attachments:

• 1167340105-asym_angles_2015-02-07.jpg
• 1167340092-asym_bevels.jpg
• Zatochka.png
• 1377743700-thinningSymmetryadjust.jpg

[Leo Barr]

I have sharpened a few of these – good knives – a thing that became clear on another knife the other day you will clearly see the asymmetric sides if you lay it flat on the blade it is very clear the difference on each side it is also a good test if you suspect a knife is asymmetric but you cannot readily check on the internet.
Here are a couple of pictures of a Sujihiki blue steel asymmetric I did the other week

Attachments:

• IMG_2301.jpg
• IMG_2307.jpg

[Leo Barr]

Here are a few knives with bevel details I have taken these from Japanese Chef Knives since quite a lot of these only have Japanese script on them its a handy reference for me. If you want the PDF PM me.

I had problems uploading the pdf

Attachments:

• K12.pdf
• K22.pdf

[Steven N. Bolin]

Here are a few knives with bevel details I have taken these from Japanese Chef Knives since quite a lot of these only have Japanese script on them its a handy reference for me. If you want the PDF PM me.

I had problems uploading the pdf

Yeah, I downloaded the PDFs you attached and both are no good. I definitely want to check em out so I’m going to PM you with my email address now.

Thank you, Leo!!!

[Leo Barr]

If anyone else wants this slightly messy pdf featuring the id of a few Japanese knives who only have Japanese script on them. lPM me or tell me how to post the pdf onto the site.

[Mark76]

I’m interested.

But what goes wrong Leo? The other PDFs uploaded well, although they don’t show much.

There is a file size limit to what you can upload. The limit is fairly low, around 100 MB. Other than that, I cannot see what may go wrong.

Molecule Polishing: my blog about sharpening with the Wicked Edge

[Leo Barr]

I am not sure it is possible the images in the pdf are oversized even though I reduced the size of the pdf I will reduce the dimensions of the images when I have the chance and have another go .

[Mark76]

The size of the images should not matter. It is the file size of the PDF that matters.

(Although, if there are a large number of images in the PDF, reducing its file size will seriously reduce the image quality. In that case you may consider splitting the PDF file into multiple files.)

Molecule Polishing: my blog about sharpening with the Wicked Edge

[Gerald Welsby]

Hi guys. I’ve been away for a while, and come back to find this interesting topic. Firstly, I’m pretty well convinced that when a knife is specified as being ground 60/40 or 70/30, the numbers refer to the ratio of the angles, not the widths of bevels. In fact, assuming you want your edge to be in the centre of the knife it makes little difference. For example (assuming that my 40 year old trigonometry still serves) taking Leo’s case of a 60/40 split (1.5:1) on a 30° included angle, the ratio of bevel widths comes out at about 1.476:1.
It got me wondering though, how the WE would handle it. I think that initially it would sharpen to the lower point of the two sides. So, the burr would be formed with the edge offset toward the side with the lower angle. Thereafter, you would have to to sharpen only the side with the more acute angle until you judged by eye that the edge were in the centre of the blade.
What do you think?
Gerald.

[Steven N. Bolin]

Misono UX10 Sharpened on Wicked Edge

[Author]

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