Asymmetry – The REAL DEAL

[Zwiefel]

This is how i understand it :



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

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).

[Korin_Mari]

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..

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!

[Dave Martell]

I'm always glad to hear someone agreeing with me.....LOL

Thanks Mari

[lanel]

Do you advocate steeling the 70/30 edge and if so what sort of steel do you reccommend?

[knyfeknerd]

Do you advocate steeling the 70/30 edge and if so what sort of steel do you reccommend?

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.

[Yoni Lang]

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..

[bieniek]

I made some HQ image of whats happening and I would ask you guys to opinionate



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.

?

[ThEoRy]

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?

[Dave Martell]

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.

[chinacats]