Asymmetry – The REAL DEAL

[ThEoRy]

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.

"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..."

[Dave Martell]

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.

[jayhay]

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.

[Yoni Lang]

Amazing people even take the time to make videos like these.

agreed

[Slypig5000]

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.

[tripleq]

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!!

[Dave Martell]

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!!

I'm happy that you got something from this Norm.

[sharp knfing]

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

[Dave Martell]

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

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.

[sharp knfing]

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