Little bit of trouble with the (blue) JNS Aoto Matukusuyama

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Hi there,

I thought I would post this here as it's a specific question and I'm hoping to reach others who use this stone.

I've been using it for a few months, but I've not been completely happy with the edge I've been getting (on various steels, blue#2, victorinox, CCK).

I mostly use the SP1000 and I'm very comfortable with it. I get a burr, flip, burr, flip again, lighter pressure, burr, flip, lighter pressure, burr, then do some alternating stropping strokes (5,5,4,4,3,3,2,2,1,1,1,1,1,1 or something like that) until the burr is gone (but depending on the steel, I may do some edge leading strokes to remove the burr a bit more aggressively earlier on). This gives me a good, sharp edge. I can push cut newspaper against the grain.

But I move on to the Aoto to refine it a bit. I use lighter pressure, not aiming to make a burr, but just looking at the scratches on the bevel. I finish in the same way (light stropping strokes). The first few times I used it, I kinda felt a more refined edge, but I also noticed it was not as sharp. It would slice newspaper in a more refined way, but it would no longer push cut it (in any direction).

I noticed the stones surface was not flat (which must have happened from factory), so I flattened it, and this helped, but it was still not as sharp as the SP1000. I had another go the other day, and I was about to give up, and when I was putting the stone away I realised the surface was not clean. I had not been using a nagura of any sort (I usually look at the surface to see if it's clean, but because of the colour, I realised you cant see any grit). So I got a nagura and cleaned it up and finished again with stropping strokes. The stone felt completely different, much less resistance as the knife went over it (much faster, like skating on ice), and I got a better edge. Improvement.

But I tried another knife yesterday (blue#2 petty), using the SP1000, and then the Aoto, making sure the Aoto's surface was flat and clean. My final edge was definitely better than before, it cut the paper well, but I still felt it was not as sharp as the SP1000's edge. I'm not expecting the Aoto's edge to be sharper, but just more refined (although I understand it's a mix of grits, but it's still higher grit than the SP1000), but it's the fact that I feel it's getting less sharp that I'm possibly doing something wrong.

Doing just a couple of swipes on a leather strop improves things, so I'm wondering if there's a tiny burr, but if there is, surely there would also be a burr after the SP1000? I also did not have this problem going from the SP1000 to the SP5000, I always felt a big improvement in terms of sharpness and refinement (although I have since sold that stone as I didn't enjoy using it)

Thanks
 

MowgFace

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Ref-

I also have the JNS Blue Aoto and find that it is a great stone! Usually i use it for touch ups, but it serves as a final edge for a couple of my knives. One stainless and one carbon. I literally have never used a nagura on it, so i doubt that the stone can be causing anything.

Usually when threads like this come up the root cause seems to be angle consistency &/or deburring most of the time. Most recommendations are to go slow, utilize the sharpie trick, and deburr, deburr, deburr. I do not believe this to be any different.
 

Desert Rat

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I have seen edges with less tooth perform worse on paper. Try something you have to slice like maybe a paper towel or kleenex.
 

Steampunk

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Sounds like either a residual burr problem, or - more likely - convexing. The JNS Blue Speckled Aoto is a medium-density stone, and the softness can sometimes create more edge bevel convexity than hard or ultra-hard stones like Shapton. That convexity can rob you some of that 'crispness' that one looks for in edge tests. My JNS Blue Aoto is a lovely stone in terms of feel, especially since I've been perma-soaking, but doesn't create the edge I like on most of the steels I use... I like it on D2/SLD.

My guess? This isn't 'your edge'... Keep looking. You'll find your favorite finishing stone(s).

- Steampunk
 

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I also have the JNS Blue Aoto and find that it is a great stone! Usually i use it for touch ups, but it serves as a final edge for a couple of my knives. One stainless and one carbon. I literally have never used a nagura on it, so i doubt that the stone can be causing anything.

Usually when threads like this come up the root cause seems to be angle consistency &/or deburring most of the time. Most recommendations are to go slow, utilize the sharpie trick, and deburr, deburr, deburr. I do not believe this to be any different.
My angle is quite good now, but I will try make sure there's no burr left. The thing which confuses me is that I definitely don't have a burr left over on the SP1000, and I'm doing the same thing (lighter pressure in fact) on the Aoto.


I have seen edges with less tooth perform worse on paper. Try something you have to slice like maybe a paper towel or kleenex.
I will try this too thanks

Sounds like either a residual burr problem, or - more likely - convexing. The JNS Blue Speckled Aoto is a medium-density stone, and the softness can sometimes create more edge bevel convexity than hard or ultra-hard stones like Shapton. That convexity can rob you some of that 'crispness' that one looks for in edge tests. My JNS Blue Aoto is a lovely stone in terms of feel, especially since I've been perma-soaking, but doesn't create the edge I like on most of the steels I use... I like it on D2/SLD.

My guess? This isn't 'your edge'... Keep looking. You'll find your favorite finishing stone(s).

- Steampunk
What stones do you usually use to get the edge you like on most of the steels you own?
 

Steampunk

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What stones do you usually use to get the edge you like on most of the steels you own?
Oft, I favor naturals... J-Nats, Belgians, or Arkansas depending on the knife in question. Sometimes synthetics... Here's a review thread I started with some notes on stones I use:

Stone Review Thread - 3-6K Synthetics...

If we're talking about the Aogami #2 you own, I favor Belgian Blue's, and probably the Shapton GS 4K or Gesshin 6K S&G.

For the Victorinox, Soft Arkansas or a good White Binsui, or the JNS 800 Matukusuyama is probably the best places I've stopped.

CCK (Assuming Carbon), I'd probably go Hard Arkansas, Naniwa Pro 800, etc... Nothing too high.

Arks are close to peerless on soft, simple steels, but are unforgiving to use and slow, and worthless on alloyed steels with hard carbides. The JNS 800 is a real workhorse on soft western SS like Victorinox. Belgians cut Tungsten steels very effectively for a natural; better than J-Nats.

Steels are unique. There's no one stone that suits every knife, or creates a finish for every situation. It's also quite a personal decision; it takes some experimentation to figure out what you like.

Hope this helps...

- Steampunk
 
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