Asymmetry – The REAL DEAL

Japanese Knives - by Tokushu Knife
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dbesed said:
This is how i understand it :

grinds.png


The right is the right side of a knife when you hold it in the hand. I think that Dave talks about picture 3.


Please corect me if i am wrong :sad0:
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fantastic graphic...thank you!

I think I understand what Dave is promoting....either of the first or the last in this picture, right? Not the middle two.

I just don't understand why (like some of the others).
 
Dave Martell said:
EdgePro type device retailers will tell you to just pick an angle and grind more from one side than the other or maybe to count strokes (like 7 strokes on this side and 3 on another for 70/30 grinds)…..they state that this will allow for correct asymmetrical ground edges. I respond to this by stating that this is an irresponsible solution to tell people to sharpen their knives this way as I know from my years of experience that this will only lead to an unevenly sharpened knife that steers and wedges while cutting.

So if you’re using an EdgePro type device and you have to adjust the stone arm’s angle for each side of the knife to properly hit the edge bevel in the correct position then do so. Yes this sucks but this is what you’ve decided to use to sharpen your asymmetric Japanese knives with. If you’re upset with having to do this then tell this to the people who sold you the myth, but sharpen your knives correctly..
Click to expand...

Omg thank you. Yes, it is just an incredibly irresponsible solution to give people who just want to sharpen their knives. I have had so many people come up to me and tell me about their Edge Pro recently. I had no idea what it was, until I youtubed it. It looks silly and I wasn't sure if it actually worked, but you just answered by question.

Awesome post by the way!
 
Do you advocate steeling the 70/30 edge and if so what sort of steel do you reccommend?
 
lanel said:
Do you advocate steeling the 70/30 edge and if so what sort of steel do you reccommend?
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First of all, it depends on what type of steel the knife is and what you are using as a honing rod. I only use steel rods for german knives/soft steels, etc.
When I do hone my knives that are 70/30 or any other asymmetric bevel, I use a ceramic rod. The most important thing is to adjust your honing angle to that of the edge. I sometimes will view my placement of the edge against the rod by looking at it from the top to begin. Just to make sure my angles are right.
 
Thanks Dave for this.. had a lot of questions and found this topic to answer a lot of them.. I feel over the past year or so I've complicated sharpening by not fully understanding the basics before moving onto some of the more advanced aspects of sharpening. Think I had a better grasp on sharpening when I was first being taught. This definitely steered me back on to the right track.. Still lots of questions though... Not sure where this thirst for sharpening knowledge has suddenly come from.. Maybe working with people with razors has opened my eyes to what an actual sharp knife is, or maybe it was when someone asked when the last time I sharpened my butter knife was.. :laugh:
 
I made some HQ image of whats happening and I would ask you guys to opinionate

Beznbsptytu1420u_zps52cc84ca.jpg


So what we have here is a knife assymetrically ground be it Misono Swedish, but with a 50/50 same size and angle bevels on both sides.

My understanding is that

1. because of how the blade is ground, when cutting [a carrrot] the right side is trying to push the produce to the right hand side.
2. Because the bevel on left han side is significant it tries to push the whole blade to the right hand side, and wedging occurs.

?
 
Ever try to cut a piece of wood with a circular saw between two supports? Don't do it! I can imagine this might be similar. Pressure from both sides of the product pressing into the blade causing the wedge perhaps?
 
A member sent me the link to this video and after reviewing it I thought it warrants that I show it here in this thread.

The video demonstrates exactly what I was talking about when I mentioned how you have to be careful who you get your information from on this subject. Here we have a guided sharpening system salesman talking about his take on how to grind asymmetric knives. I find this demo all wrong - just wrong.

Besides the worst belt grinder technique seen on the interweb...

1. The knife being used IS NOT a Japanese asymmetric knife - it's a super market western made 50/50 clunker. You can't possibly demo this topic on a 50/50 ground knife!

2. He's "showing grinding at a constant angle" yet he's free handing which isn't "holding a constant angle" at all.

3. He talks about how grinding more from one side of the knife than the other is how you adjust the asymmetric ratios. This is true of coarse - but only if you're talking about skewing the ratio so bad that the f-ing knife steers, twists, and cleaves your food apart. This is so basic of an understanding to me that I'm stunned to see him make these comments and demo this in public.


So even though I don't believe in promoting this guys BS I'm posting this for everyone to see the exact opposite of what the REAL DEAL on asymmetry is.


[video=youtube;dDsWh_M7Rek]http://www.youtube.com/watch?feature=player_embedded&v=dDsWh_M7Rek[/video]
 
Dave Martell said:
A member sent me the link to this video and after reviewing it I thought it warrants that I show it here in this thread.

The video demonstrates exactly what I was talking about when I mentioned how you have to be careful who you get your information from on this subject. Here we have a guided sharpening system salesman talking about his take on how to grind asymmetric knives. I find this demo all wrong - just wrong.

Besides the worst belt grinder technique seen on the interweb...

1. The knife being used IS NOT a Japanese asymmetric knife - it's a super market western made 50/50 clunker. You can't possibly demo this topic on a 50/50 ground knife!

2. He's "showing grinding at a constant angle" yet he's free handing which isn't "holding a constant angle" at all.

3. He talks about how grinding more from one side of the knife than the other is how you adjust the asymmetric ratios. This is true of coarse - but only if you're talking about skewing the ratio so bad that the f-ing knife steers, twists, and cleaves your food apart. This is so basic of an understanding to me that I'm stunned to see him make these comments and demo this in public.


So even though I don't believe in promoting this guys BS I'm posting this for everyone to see the exact opposite of what the REAL DEAL on asymmetry is.


[video=youtube;dDsWh_M7Rek]http://www.youtube.com/watch?feature=player_embedded&v=dDsWh_M7Rek[/video]
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"My name is Ken ******** and I'm going to show you the traditional way to sharpen a Japanese knife with this Target brand knife on a belt grinder..."

wth.jpg
 
What he doesn't get, or address, is that it's not about making a choice to either grind more (from one side or the other) or change angles (on one side or the other) - it's about doing what the specific knife's edge requires (which might be a combination of both or whatever method) needed for each side (edge) to stay in relation to the blade's asymmetric shape.
 
Wow, Kens voice is really annoying. I've never used a Burr-King, but do you really have the belt cut towards the knifes edge? Seems like it could grab the edge if you grind at too high of an angle, and shoot the blade at your body.

Amazing people even take the time to make videos like these.
 
I read this this morning, I know it's not a j knife, but I have a 40 year old beater dexter that I resharpened to 80/20. Curious to see what this does for the knife.
 
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Hey Dave. I know I'm late to this thread but I wanted to let you know that it shed some light on a few things for me. When I started sharpening I would hold my angles the same on both the right and left side and just as you describe I saw less bevel on the left side vs the right. I started adjusting my left side angle lower (or right side higher) till I had about the same amount of bevel on each side. I never really questioned what was behind it but I felt it was of importance. Thanks for taking the time to explain it!!
 
tripleq said:
Hey Dave. I know I'm late to this thread but I wanted to let you know that it shed some light on a few things for me. When I started sharpening I would hold my angles the same on both the right and left side and just as you describe I saw less bevel on the left side vs the right. I started adjusting my left side angle lower (or right side higher) till I had about the same amount of bevel on each side. I never really questioned what was behind it but I felt it was of importance. Thanks for taking the time to explain it!!
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I'm happy that you got something from this Norm. :)
 
Sp lets see if I finally have this....

Using the example diagram of an asymmetric flat grind with an asymmetric 70/30 bevel on a right handed knife , to achieve a 30 ° included angle , the angles would be:
Left side of blade 70 X 30°= 21°
Right side of blade 30 X 30°= 9 °

Am I off on this?

Thanks in advance

Douglas
 
sharp knfing said:
Sp lets see if I finally have this....

Using the example diagram of an asymmetric flat grind with an asymmetric 70/30 bevel on a right handed knife , to achieve a 30 ° included angle , the angles would be:
Left side of blade 70 X 30°= 21°
Right side of blade 30 X 30°= 9 °

Am I off on this?

Thanks in advance

Douglas
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IMO it's a mistake to apply math, or to make a set rules to follow, when sharpening these knives. I feel that you'll be best served by following the asymmetry of the blade when sharpening vs using angle measurements.

If you're just trying to understand the principle, then you're warm. :)

Well what I mean is that you're part of the way there, what you're missing is that we're talking about approximates with hand made knives so there's no rules that apply hence you're not going to do well if you try to figure out an exact ratio and then use math to sharpen to specific angles. You are getting the rough idea of it all correct though.
 
Thanks for the reponse.
I have sharpened 2 asymmetrical knives to equal angles on both sides and would like to get them back to what it was designed.
While math might not be the exact answer at least it will put me back in the ballpark.

Thank you for the info.

Douglas
 
I am picture sort of person, so the more I read the more puzzled I become. Is there a link with pictures within this forum? :dazed::scared4:
 
smilesenpai said:
I am picture sort of person, so the more I read the more puzzled I become. Is there a link with pictures within this forum? :dazed::scared4:
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There are a few illustrations on page 6&7. Did those help?
 
tripleq said:
There are a few illustrations on page 6&7. Did those help?
Click to expand...

I didnt see those. I read up to page 4 and was so lost, hence the post.

Those do give me a better idea. I will do more, reading now I have see these images and hopefully, I make more sense of this.

Cheers.
 
Wait, I have a 2 questions that I don't think has been addressed regarding kens demo. 1) why the hell would you have to set the platen to any degree of a angle? I mean at any degree is it not still the flat platen and edge angle going to be the same? 2) and more important isn't he messing up the whole font part of that knife by follow the curve of the knife? It looks to me tat the scratch pattern is laving the front part to thick and destroying the tip in the same move? Wouldn't it work better and be easer if he just kept the knife straight?
 
Chef Niloc said:
Wait, I have a 2 questions that I don't think has been addressed regarding kens demo. 1) why the hell would you have to set the platen to any degree of a angle? I mean at any degree is it not still the flat platen and edge angle going to be the same? 2) and more important isn't he messing up the whole font part of that knife by follow the curve of the knife? It looks to me tat the scratch pattern is laving the front part to thick and destroying the tip in the same move? Wouldn't it work better and be easer if he just kept the knife straight?
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He is the expert! :D
 
Chef Niloc said:
Wait, I have a 2 questions that I don't think has been addressed regarding kens demo. 1) why the hell would you have to set the platen to any degree of a angle? I mean at any degree is it not still the flat platen and edge angle going to be the same? 2) and more important isn't he messing up the whole font part of that knife by follow the curve of the knife? It looks to me tat the scratch pattern is laving the front part to thick and destroying the tip in the same move? Wouldn't it work better and be easer if he just kept the knife straight?
Click to expand...

:popcorn:
 
I've just recently sharpened my first 2 asymmetric knives beyond 70-30 and realized what a HUGE learning curve it is. These were my buddys knives and one was his first Yanagi (a Masamoto) and another was a Misono UX-10 he'd set up to about 99 and 1. He had obviously been learning himself when he sharpened these and I quickly realized what a mess he'd made of the edges and how far I had to go to learn proper asymmetric sharpening.

Firstly, it felt wrong sharpening at these angles , secondly, he had not done them well. I feel like I am now ready for a single bevel of my own to learn properly on but one that doesn't have the multitude of crazy bevels he had on his.

Couldn't have learned any of this without the knowledge from this forum. Thanks guys.
 
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