Interesting post and SEM images of dual grit sharpening on Scienceofsharp.

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A burr forms the edge. We know this bug, Here it migt be a feature.

Grinding with pressure can bend up the edge. This way material can be be taken off behind the edge and leave a burr of undamaged steel. But what are the effects of dual grit sharpening?
 
I guess the only real advantage is because most people wouldn't be able to push that burr like that on the same stone, a very fine grit would just be easier to handle as it would make some residual burr at best. Funny enough, there's some mentioned there.
 
For us and kitchen knives that are regularly sharpened at 9 to 15 degrees, I'm not thinking this particular technique would have any real advantage but thought it cool and out of the box. Love that with SEM we can actually see what going on on the edge instead of imagining it. Cant tell you how many of my imagined scenarios have been totally off base over the years :)
 
But something is somehow missing. 1:1 comparison over Maxamet, diamond/cbn edges constantly outperformed other abrasives. Cbn finish always outperformed spyderco UF and Glass 16k. And that sounds like something impossible. So the real question is why. Because, let's say okay, it's as seen, why do we experience something else? I won't even go to other results, studies. I just need an opinion about this one.
 
what i'm interpreting from this is that all coarse stones will create a burr, and if its flexed it will have cracked carbides in it.
then i see that all coarse stones wear and/or pulverize carbides to some degree.

woulds be nice to see more of higher grit stones used in this test. maybe a 2-6k diamond/sic/alox. free hand. not guided systems.
to see if this also creates a burr with cracked carbides or if it will simply look like the maxamet/jnat result.

i will have to read both of these again.
 
So... Has anyone actually tried this technique on japanese kitchen knives?
 
So... Has anyone actually tried this technique on japanese kitchen knives?

I've never tried that, but I would guess that impacting the board would weaken the "good burr" and roll it/fold it/break it over time.

Not having an SEM to test at home, sadly, and having techniques that work great already, I'll stick to what works for me rather then risk losing extra steel off the edge if this doesn't work well for a kitchen knife.
 
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So... Has anyone actually tried this technique on japanese kitchen knives?
I can’t say I have tried creating such an edge myself, but I had a honesuki that was intentionally finished low(er) grit on one side and higher on the other from factory - masakage yuki. I can dig the sharpener’s stamp up if you want to know who it is. Didn’t notice much difference in the edge performance vs single finisher, but deboning chicken thighs doesn’t give me much fine feedback. Sadly that stock edge is long gone, I touch it up before each use because I suck at deboning.
 
My Yuki had a crazy good factory edge, one of the best I've ever seen.
I agree, it definitely wasn’t one of those “choose your own adventure” type of edges, very deliberate and well done finishing.

Now that you mention it, maybe I do some experimenting. Maybe not for the mythical good-burr, but this type of hybrid edge.
 
@Cliff @Pie - Masakage Koishi also comes with a hybrid edge. When I received the knife I asked Ellie @ Knifewear about it, and it's apparently 800/8000. I didn't keep it up, but OOTB sharpness was best I'd had until my Watanabe nakiri arrived. I believe the Koishi sharpener is Takayuki Shibata, possibly Yuki line too, not sure.

Edit: corrected grits from 1000/4000, which Ellie says should also work.
 
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Does it matter which edge is which? Sharpen the right side with the 1K and then deburr with the 4K? My Wat Gyuto came with a zero grind I was too scared to use.
 
Does it matter which edge is which? Sharpen the right side with the 1K and then deburr with the 4K? My Wat Gyuto came with a zero grind I was too scared to use.
Can't believe such an edge is meant to be actually used for board work. Looks to me rather as a kind of service to the end user, who can put his own edge on it with only a few strokes.
 
@Cliff @Pie - Masakage Koishi also comes with a hybrid edge. When I received the knife I asked Ellie @ Knifewear about it, and it's apparently 800/8000. I didn't keep it up, but OOTB sharpness was best I'd had until my Watanabe nakiri arrived. I believe the Koishi sharpener is Takayuki Shibata, possibly Yuki line too, not sure.

Edit: corrected grits from 1000/4000, which Ellie says should also work.
I feel kinda dumb for scrubbing the stock edge away if shibata was the last guy to work on it 😬. I was told something similar by the guys at Knifewear, I mean it sounds sexy from a marketing perspective but I’m not sure if the real world application of such edges. I too have been nervous about/experienced the stock zero edge, on both my mazaki’s. Sharp, but inconsistent and lacking durability. At this point in the journey I’m a fan of the opportunity to pull out the stones.

My hypothetical mixed edge would probably end up NP400/medium jnat finisher.. got crazy good results with @branwell’s hybrid edge method.

I really need more stuff to sharpen :(.
 
Do you go from NP400 to a Natsuya/Aoto? Seems like a big jump to me.
Oh man I go 400 to like… 5-8k mirror finisher - it’s a mean, fast suita. Huge jump but this stone can handle it, it eats deep scratches for breakfast. My ultra fine finishers I’m still not confident enough to produce consistent, reliable results.
 
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