Naniwa Aotoshi 2k Green Brick - "green brick of joy"
August 19, 2014 05:42PM
This is a massive stone : 2 3/4" x 8 3/8" x 2 3/16" and it is one of the most commonly praised stones on the internets.

-cut with the speed of a 1k stone
-gives the finish of a 2-3k stone
-feels silky smooth, almost like a natural japanese waterstone

and the only complaint is :

-it dishes very fast

and the neutral description :

-it is muddy

A few comments from the forum :

" I have one, and have not had good luck with it...well it's worked well to increase the edge polish but not the sharpness."

-[www.cliffstamp.com]

and :

"I have a love hate relationship with this stone, and it all depends on what knife i am using. IMO this stone excels with carbon steels like 1095 or stainless steels like AUS8. With those steels the stone produces a nice mud and gives excellent refinement. The stone gives decent feedback during use and again depending on the steel it can load super fast. I use this stone splash n go style as well as i havent seen any benefit of soaking it. Of all the stones this one requires lapping the most. You can get a really nice edge off this stone depending on the steel, mud, and wheither or not its loaded or not. For polishing let the stone load, then start, but for sharpening the stone needs to be freshly lapped, and if it is not producing a slurry, either lap it a few times or I have found using a simple cheap kitchen knife works up a nice mud then i will switch to whatever knife i was going to work on. Im on the fence about this stone, as for some steels its great but others not so much, so I dont know if the value is there or not. "

-ref : [www.cliffstamp.com]

Now a few details :

-it is so massive I can't fully soak it, though I will at some point
-it needs a lot of water, but again I don't have it fully wet
-it forms a slurry so fast/thick that it would be described as muddy

This is it dry :



It is very fine (no surprise).

I had not been intending to use it yet but I had been having some chipping problems with the Maxamet mules : [www.cliffstamp.com] and even the well used Bester 700 was giving a much more coarse finish than I would want (pre-DMT 600) :



I decided to throw it in the deep end and use it to sharpen a 69 HRC maxamet mule. To be clear I did the prep work on the Bester 700 but stopping just as the light started to be removed from the edge. I only did 250 pps on the Naniwa and it looked like this :



The reason why it is so dark is because the bevel is becoming reflective (mirror) and it is overloading the sensors. This is also without any burr removal/minimization techniques. It certainly does appear to behave as it is described :

-the very high rate of mud gives constant fresh abrasive

which explains :

-the high cutting speed, high finish and fast rate of wear

This brought the edge up to speed so fast on a very hard to grind steel when I was working the primary so it is likely possible that this could prep edges that were not visibly damaged.

Now for the downside, the very high rate and thick mud formation that this stone produces is likely to give people fits unless they know exactly how to deal with it because if you don't then what will happen is that the edge will look very polished but will not actually get sharp and could in fact actually start to dull.

In addition to that, because it is soft and wears rapidly then it will start to add a curve to the edge and thus if you jump from this to a much harder higher grit stone then nothing will happen and the edge will now start to feel horrible because you will have convexed it but then it will start to rock/plane on the harder stone.

In short, I can readily see how this stone gets so much praised as a prep stone but really can frustrate people at the same time. It will be interesting to work with.


PB album : [s7.photobucket.com]
Re: Naniwa Aotoshi 2k Green Brick - "green brick of joy"
August 20, 2014 04:58PM
very nice review Cliff!

So when you say "thick mud formation that this stone produces is likely to give people fits unless they know exactly how to deal with it because if you don't then what will happen is that the edge will look very polished but will not actually get sharp and could in fact actually start to dull..." what is the proper way to use water stones? Do you have any sources I could read up on that you would recommend?
Re: Naniwa Aotoshi 2k Green Brick - "green brick of joy"
August 20, 2014 05:04PM
I think Cliff is getting at the following:

As you approach the apex, or if you have apexed and are now looking to sharpen the mud will only hinder you because as you are plowing through it, while yes, the apex is being abraded, it is also being smashed into the grit contained in the mud, so it kind of becomes a stalemate without the refinement of the apex necessary for actual sharpening.
So once you are at that point you have to clean the mud off the stone, make sure it is flat, and then sharpen with light pressure, essentially avoiding mud development.

_______________________________________________________________________________________________

Always in search of a good choppa'
Re: Naniwa Aotoshi 2k Green Brick - "green brick of joy"
August 20, 2014 06:06PM
Essentially, the thing to realise though is that the slurry/mud is part of what is cutting and the reason it gets so polished. If you rinse it off then the finish will be degraded though it is easier to sharpen it then. This is why the razor guys will build up a slurry, get the edge to the polish they want and then start diluting the slurry to keep that fine abrasive mix -but- thin it out so it rounds the apex less and less.

However unless you really have to constrain yourself to that stone I would recommend that you treat the Naniwa Aotoshi as a prep-stone and once the bevel is polished and the apex ready then finish it on a finer and slightly harder stone which isn't muddy. This assumes you want to retain the polish, or you can just micro-bevel with a coarse stone as well.

You can also try very slow and edge trailing passes to minimize the slurry rounding off the apex and as well when you are building up the slurry use very light force so that you break down the slurry which forms rather than constantly grind new abrasive into it. Note as well that not all parts of the stone will have the thick slurry and you can also let it dry out to create a new surface to work with.

There are many ways to use a soft / muddy stone so experiment a little.

However they can be very frustrating/aggravating if you focus on the actual apex refinement and the sharpness produced from it so I would recommend always have the viewpoint/goal of using them as prep stones as shaping stones as scratch removal stones. This way there is no negative when/if the apex doesn't actually get sharpened and it is stress free.


Basically I take the edge from the Bester 700, note that I want to refine the apex to remove all scratches, minimize the burr and have a nice and even apex line as prep for the DMT micro-bevel. If it is actually sharp - excellent, but the goal isn't really there specifically. But if it comes, then that isn't a problem.

The maxamet mules will all dry shave (arm) easily from the Naniwa Aotoshi even though there is no burr minimization done and I don't specifically try to refine the apex (shaping only). These may sound like word games, however your brain is really quite stupid and your ability to perform when you are happy is much higher (for most people) than when you are aggravated, so be happy and make sure your focus is where it should be.



Edited 1 time(s). Last edit at 08/20/2014 06:11PM by CliffStamp.
Re: Naniwa Aotoshi 2k Green Brick - "green brick of joy"
August 21, 2014 04:13PM
Quote
CliffStamp


To be clear I did the prep work on the Bester 700 but stopping just as the light started to be removed from the edge.

After sharpening all of the Mules now I need to refine this statement. The Naniwa Aotoshi 2k doesn't cut as fast as the Bester 700, it is significantly slower. This isn't surprising but the speed of this stone is often a bit over claimed (cuts as fast as a 1k). Now it cuts well, but if it cuts as fast as a 1k stone then you have a pretty slow cutting 1k stone.

Ideally I catch the edge on the Bester 700 just as it is about the apex and then I can set the edge with a little work on the Naniwa Aotoshi. However if I try to do it a little too early I can do 1000 passes on the Naniwa and little to nothing happens. Now to be clear this is me trying to minimize steel loss (and having a bit of a challenge/fun) if you don't care about than and just want maximum speed then just apex on the Bester 700[*] and then refine on the Naniwa Aotoshi before the final apex bevel.

[*] well ideally you apex on something a bit more coarse as the Bester 700 can take > 1000 passes on some of these hard to grind steel when I am working a large bevel.
Re: Naniwa Aotoshi 2k Green Brick - "green brick of joy"
August 23, 2014 05:04AM
Out of curiosity, what are you using to flatten this stone? Do you use a finer stone or just the regular cheap hardware store stone?

_______________________________________________________________________________________________

Always in search of a good choppa'
Re: Naniwa Aotoshi 2k Green Brick - "green brick of joy"
August 23, 2014 11:51AM
Quote
C Amber
Out of curiosity, what are you using to flatten this stone?

I will use the Bester if it needs to be flattened, otherwise the hardware store stone however I have not as of yet. It still shows perfectly flat with a metal rules. I have just under 10k pps on it so far but I have been experimenting with a few different honing patterns to even out wear and periodically using a very small coarse stone to just work the stone over like a sort of mini-flattening.

--



This is after 750 pps (1500 passes total) and you can see how it brings up mud heavily (the big glob on the side). This is a very soft/muddy stone. I am only using very light force here, 1-2 lbs and working on a very wide bevel 1.5 cm so the pressure is very low. Ideally you want to use just enough force so that the much just barely forms (as otherwise you are wasting abrasive). However it is difficult to do that with this stone because it is just so soft.



Here is an assortment of some cheap kitchen knives, all very soft, low carbide steels. They all had light reflecting from the edge and the edge was cut off with two cuts into the Bester 700. I attempted to use the Naniwa Aotoshi to sharpen and use less than 1 lbs to reduce the mud formation/wear, but it was not practical :

-Levco utility, 1000 pps, light still strongly reflecting
-Martha Stewart Chef, 500 pps, light still strongly reflecting

I then attempted the Henckels which has the original very narrow bevel (< 1 mm wide) and it still took 875 pps to apex the bevel. In short it isn't practical to resharpen by itself on knives which are seriously blunted (but not damaged). This isn't surprising of course. To apex the knives I used the Bester 700 which took :

-Levco, 125 pps
-Japanese Bread knife, 250 pps
-Wiltshire Chef, 250 pps
-Martha Stewart Chef, 75 pps

These all have very close to zero bevels so the part being sharpened is fairly wide, > 1/8" .

--

Now of course if I didn't cut the edge back on the Bester 700 to start it would be likely that the Naniwa Aotoshi should be able to micro-bevel the knives to keep them sharp and as well if the knives were just blunted but not used so harsh that they showed visual impaction then it likely could work the entire bevel as well.
Re: Naniwa Aotoshi 2k Green Brick - "green brick of joy"
August 23, 2014 12:06PM
Thank you for the answer, and for the look at the other work.

Doesn't look like it would be great as a one stone option for regular sharpening unless the work one does is generally very low stress.

_______________________________________________________________________________________________

Always in search of a good choppa'
Re: Naniwa Aotoshi 2k Green Brick - "green brick of joy"
October 20, 2014 05:48PM
This is proving to be a very nice prep stone :



That is on a 3Cr13 steel, ~5 dps :

-Suehiro Chemical, intentionally over ground to a visible burr (as an experiment)
-No burr removal specifically, just grinding on the Aotoshi

The edge push cuts exercise paper at ~1/2" from the point of hold without even trying to sharpen it on the Aotoshi. Now this is a very easy to grind steel and easy to sharpen if you understand how it works (can be frustrating if you don't). With a steel with a much lower grindability this won't work and you have to do something like :

-Suehiro Chemical, ideally not to apex
-Naniwa Superstone 400, to apex
-Naniwa Aotoshi

This leaves the edge in near perfect form for micro-bevels, even ones with very high polish, i.e. MXF DMT, or Spyderco F, etc. .
Re: Naniwa Aotoshi 2k Green Brick - "green brick of joy"
October 21, 2014 04:30AM
Quote
CliffStamp
Now this is a very easy to grind steel (3Cr13) and easy to sharpen if you understand how it works (can be frustrating if you don't).

Do you mean very prone to hard to remove burr formation? A burr that will just flip flop a lot

Quote

With a steel with a much lower grindability this won't work and you have to do something like :

-Suehiro Chemical, ideally not to apex
-Naniwa Superstone 400, to apex
-Naniwa Aotoshi

This leaves the edge in near perfect form for micro-bevels, even ones with very high polish, i.e. MXF DMT, or Spyderco F, etc. .

Is this because forming a burr on the Suehiro, or just apexing even would leave the edge very jagged from the large grit size?

_______________________________________________________________________________________________

Always in search of a good choppa'
Re: Naniwa Aotoshi 2k Green Brick - "green brick of joy"
October 21, 2014 04:49AM
Quote
C Amber

Do you mean very prone to hard to remove burr formation? A burr that will just flip flop a lot

Yes exactly and once it is formed it will tend to bend vs just cut off. A somewhat muddy stone tends to prevent it and form an apex which is just under sharp but not burred which can then be easily finished. However if you spend too much time and put too much force into it then you will just push the edge around again. Of course any of this only matters if you are trying to obtain very high sharpness.

Quote

Is this because forming a burr on the Suehiro, or just apexing even would leave the edge very jagged from the large grit size?

Yes and the low grindability means the Aotoshi would not be able to take them out as the cutting speed would be far too low.
Re: Naniwa Aotoshi 2k Green Brick - "green brick of joy"
October 21, 2014 10:17AM
Here is a link I turned up then lost, found again :

- [www.chefknivestogoforum.com]

Explanations?
Re: Naniwa Aotoshi 2k Green Brick - "green brick of joy"
October 21, 2014 11:33AM
Explanation? How about 3 posts up from this smiling smiley

_______________________________________________________________________________________________

Always in search of a good choppa'
Re: Naniwa Aotoshi 2k Green Brick - "green brick of joy"
October 25, 2014 11:00AM
Edge retention, initial sharpness, micro-bevel setting : [www.cliffstamp.com] .
Re: Naniwa Aotoshi 2k Green Brick - "green brick of joy"
November 11, 2014 05:41AM
I just got another CRKT Veff MUK, after my original two where lost, and it's 2Cr13 steel, and it's burr is a real pain to get rid of.



Edited 1 time(s). Last edit at 03/29/2015 02:40PM by CliffStamp.
Re: Naniwa Aotoshi 2k Green Brick - "green brick of joy"
November 11, 2014 07:58AM
Quote
jasonstone20

[...]

I just got another CRKT Veff MUK, after my original two where lost, and it's 2Cr13 steel, and it's burr is a real pain to get rid of.

I have not used that knife, but the simplest solution to this is to use a very muddy stone which is very resistant to heavy burr formation. If one does form then use the same stone with double the edge angle to micro-bevel with 1-2 light passes, alternating sides. This heavy micro-bevel doesn't need to be left on, it is just to cut the bevel off.
Re: Naniwa Aotoshi 2k Green Brick - "green brick of joy"
November 11, 2014 08:15AM
As a general update on this stone, the one big issue I have with this isn't an issue specifically but it relates to the fact that it is much more slow wearing than the stones that proceed it. If I am doing a find finish I can typically run similar to :

-Suehiro 'Chemical'
-Naniwa Superstone 400
-King 1000

However when I use the Naniwa Aotoshi 2000 there is a high chance it will just facet the edge and not hit the actual apex because it will be flatter than the King and the stones that proceed it and even if they are freshly flattened they wear enough and generate thick enough mud they will slightly curve the edge. I think for those stones it would be more efficient to use a stone with a weaker binder or more friable abrasive as it would more easily match them. What I do now is slightly elevate the knife when using the Aotoshi to ensure the apex is hit.

Of course if I used different stones the Aotoshi would be preferred. For example it works well after a DMT stone for the exact same reason it doesn't work well after a King 1000. Now you can also artificially work up a very heavy slurry on the Aotoshi to force a thick mud and thus get a curvature without raising the blade, but that times time, is fairly messy and not that efficient.
Re: Naniwa Aotoshi 2k Green Brick - "green brick of joy"
November 21, 2014 11:53AM
I used this recently to sharpen a plane blade, finish was acceptable for use which was mainly trimming cedar shakes. I used it very muddy to form the apex with minimal burr, then flushed it and set a small micro-bevel. It would easily catch hairs above the skin and is likely the sharpest that plane has even been and ever will be. In general there is no reason it would not benefit from a higher finish but I think only a finish carpenter is likely to notice it and this wasn't really finish work technically (debatable but yo have to draw the line somewhere).
Re: Naniwa Aotoshi 2k Green Brick - "green brick of joy"
January 04, 2015 07:47PM
As an update, I have been using this more and more on knives which are just likely dulled, have no visible damage but can not cut newsprint well for example. I don't use it to set the apex but I use it to recut the edge and remove the micro-bevel and leave the apex ready for a new micro-bevel. It will generally do this with 100-200 pps, even with high carbide steels - again though this assumes no apex damage, just very light blunting. If the knife is used on demanding work and the apex roll/chips this stone can't be used by itself (too slow) and the edge has to be reset with something like the Suehiro 'Chemical' and then the Naniwa Superstone 400 + Aotoshi 2000 leaves the edge ready for a micro-bevel again.
Re: Naniwa Aotoshi 2k Green Brick - "green brick of joy"
January 05, 2015 04:04AM
Good update. Thank you. I didn't realize it could really cut that well, but then again I've only tried it a couple of times.

How badly is it wearing / dishing?

_______________________________________________________________________________________________

Always in search of a good choppa'
Re: Naniwa Aotoshi 2k Green Brick - "green brick of joy"
January 05, 2015 06:03PM
I don't do a lot of grinding with it, and work the entire surface so maybe 100-200 pps and I flatten it every ten sessions or so. Because I am using it intentionally to remove micro-bevels I don't even mind the 1-2 dps convexing of light wear anyway. Plus this stone is so soft you could flatten it with anything, I just use a cheap benchstone.
Re: Naniwa Aotoshi 2k Green Brick - "green brick of joy"
January 08, 2015 05:56AM
Quote
CliffStamp
The simplest solution to this is to use a very muddy stone which is very resistant to heavy burr formation. If one does form then use the same stone with double the edge angle to micro-bevel with 1-2 light passes, alternating sides. This heavy micro-bevel doesn't need to be left on, it is just to cut the bevel off.

Would it still work to add mud to a non-muddy stone by way of some loose grit? Something like 400 to 600 grit SiC. Is the burr reduction merely the result of the edge running through the abrasive mud on the surface of the stone or does the stone itself have some effect on this?
Re: Naniwa Aotoshi 2k Green Brick - "green brick of joy"
January 08, 2015 09:56AM
Quote
Mr.Wizard

Would it still work to add mud to a non-muddy stone by way of some loose grit?

I can't see how it would make much difference as long as you didn't dilute it in use.

Quote

Is the burr reduction merely the result of the edge running through the abrasive mud on the surface of the stone or does the stone itself have some effect on this?

It seems to me to be the combination of a lot of things :

-muddy stones tend to cut well as the abrasive isn't loaded/worn, this means more cutting, less ploughing

-the mud itself grind off any burr

-because of the first factor there is a tenancy to use less force, again less deformation and more cutting
Re: Naniwa Aotoshi 2k Green Brick - "green brick of joy"
January 27, 2015 03:46PM
I was interested in this stone too, but gave up looking considering the price of shipping from wherever it would be available from. Are there more common stones that behave like this one?
Re: Naniwa Aotoshi 2k Green Brick - "green brick of joy"
March 29, 2015 05:18PM
Quote
SecondCrack
Are there more common stones that behave like this one?

I just wrote up my notes on this stone : [www.cliffstamp.com]

I am not sure what you mean by behave. I tend to see this stone in the same group as :

-Naniwa Superstone 400
-King 1000

They are all equally very frustrating to use to set the apex. It can be done but it is like walking a cat, you really want to be doing it for the sake of doing it.

But as a prep stone, they are all wonderful and they make setting the final apex trivial. I have started using them all to set the final edges (depending on the micro-bevel finish). They have simplified sharpening so much there is almost no skill in it any more. Here is the basic process :

-set the edge, do any shaping with the Sigma Power 120, or Suehiro 'Chemical'

-use the Naniwa Superstone or Aotoshi or King to produce an apex

-micro-bevel, usually with the MXF DMT

As those second stones will not produce a burr readily, even if you sloppy over grind then it means all the fancy burr removal techniques are not necessary.

The only caution I would make is that with western knives with very small bevels and high curvatures then the pressure can be high enough, even if you apply 1/2 lbs or so, that you can cut into the Aotoshi readily. However it isn't needed to use such high loads on such minimal contact areas as this stone cuts well even on less than 5 psi applied.
Re: Naniwa Aotoshi 2k Green Brick - "green brick of joy"
March 29, 2015 05:37PM
Good information as usual, my impressions overlap with yours.
You mentioned things for which I have not even thought about.thumbs upsmileys with beer
Nowadays I rarely pass 1500 grit and when I do it is very hard natural local stones.
Probably I will convert my green brick in 800 grit kohetsu or 1k Shingata Akamon

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Life is GOOD!

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Re: Naniwa Aotoshi 2k Green Brick - "green brick of joy"
March 31, 2015 07:35PM
Stephen,

I rarely use ultra-high polishes, but on kitchen knives I like MXF DMT or similar, Soft Arkansas is nice as well. A really nice combination is :



-Suehiro 'Chemical' to form an apex
-Naniwa Aotoshi to polish the edge and prepare for the micro-bevel, remove the burr
-micro-bevel on Soft Arkansas

This is a very fast process. If the edge is only lightly dulled then then Naniwa Superstone 400 can be used instead. It is so fine that it can be just a two step process :

-Naniwa Superstone 400
-Soft Arkansas

This is mainly for the chopping knives, for the slicing knives then the Norton Economy/Crystolon leaves a nice finish, the Fine India a little finer which is nicer for a dual purpose type blade. Just takes a little experimenting to find the grit finish which works for the type of cutting.
Re: Naniwa Aotoshi 2k Green Brick - "green brick of joy"
May 05, 2015 07:13PM
So I managed to find a store locally that had one of these stones and I picked it up today.

I can see why they call this thing the green brick of joy. I took one of my knives and cut the edge off with 2 passes into a Spyderco medium rod, and then proceeded to remove the existing micro-bevel and eliminate light reflecting from the apex in ~50 pps. I was quite surprised at how quickly that was achieved, so I grabbed 4 other pocket knives of mine and repeated the process, each edge bevel was prepared for receiving a new micro-bevel in 50-100 pps.

My initial impression is that the cutting speed of this stone is higher than the Atoma 1200, while leaving a significantly finer finish and not forming a burr. The stone also gives much better feedback than my diamond plates (feedback in the sense of auditory and tactile indication when the angle is correct vs. not). The stone leaves an apex easily able to take a Spyderco M rod/benchstone micro-bevel.

Next time I use this stone, I'm going to let it soak for a bit longer. It didn't feel quite as muddy as this thread describes and I'd like to use it quite muddy going forwards. I am eager to see whether extended use will confirm my initial impression that this stone will often be able to function as a one stone solution for setting the edge bevels on my EDC knives.
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