Anyone has any expirence with NSK stones?

[Chasingsharpness]

Hi everyone,

im currently looking at getting some NSK stones made in a custom size. I was wondering if anyone had any expirence with them before? As far as I can see they have a softer Kyokuha line, and a harder Hakuto line. Grits seem to go up every 200 grit. they are resin bonded diamonds.

Can anyone speak to the expirence of using these stones? Are they pleasurable to sharpen on and what do they feel like? What kind of longevity can I expect with 3.5mm stone? How are they to flatten and what is the best method?

I understand these are not the most popular stones but just reaching out incase anyone has some insights,

Thank you for your time,

 

[M1k3]

@milangravier @ethompson

 

[milangravier]

I got the Hakutos 200, 400s, 800 grit and 200 grit flattening plate.
They are great stones really. Hakuto are meant to be harder, that's my preference as I work san mai blades. "s" will give a more softer stone, will be useful for honyaki to have that additional impact on hard steel.
The price is quite high for the thickness but as I am using them very often, I can tell you that with care they don't wear too fast. I am working maybe 6/8 blades per month on the 200 grit and I think it will do... 1.5 years maybe 2 years. So 100/150 blades. Not too bad ! I am speaking about shaping wide bevels on san mai blades. About.. 1h/2h (sometimes more..) of work for each knife.
200 hakuto is now my favorite coarse grit stone. It is just super nice for san mai blades, great abrasion.
400s is not my favorite, little too soft for my taste but it's really super fast.
800 is great and precise and can be followed by 1k naniwa pro.
I flatten them with sic powder 80 grit on a granit. I use the flattenning stone too but would say I am not a big fan of it, a bit too soft I would say.
Remember thoses stones and lines (hakuto and kyokuha) are made in partnership with Ivan Fonseca. He is a passionate and great sharpener in Japan and I think he will improve those stones bit by bit through the years. I just mean that what I say about those stones may change in the future as he is improving them from time to time.

About custom size stones : be ready to wait a little bit.

 

[Chasingsharpness]

Thank you for the insights.

The flatterner was something I was curious about. I usually flatten my stones with SiC on granite and atoma 140, so I was thinking if it was a must have or nice to have.

Can I ask what hardness you have? As I understand there are multiple options for the same grit within the Hakuto line. I'm thinking of starting with one stone so thinking perhaps an 800 or 1000. How would you describe the feel/feedback? I've never used a resin bonded diamond stone before. Would you say they are comperable to synthetic stones or are they quite different?

I am attempting to get In touch with Ivan so hopefully will be able to arrange something.

 

[ethompson]

I’ve used the Hakuto, Kyokuha and Oboro line extensively. I echo Milan and prefer the Hakuto. I think he touched on longevity very well.

I’ve used a several different hardnesses and also prefer the std 1 hardness. For edge sharpening the 1s might be nice as it is a little more supple feeling and slightly faster.

The feedback is different than other stones in sharpening. They aren’t glassy but like the smooth creamy feedback my favorite sharpening stones give. They do provide very accurate true to grit feel though so you know exactly what’s happening and where in the finger tips and ears. I’ve gotten some extremely nice clean bevels off mine.

These stones will ruin your atoma and become more glazed over than ever - so don’t try that. I use sic and glass to flatten and then a coarse cheap sic stone flattener to condition the surface

 

[Rangen]

Well this is interesting. Despite owning the 300 and the 10,000(!), I have no advice to offer, in the face of the great advice you are getting from people who have used these stones far more than I have. What I will say is that my time on these stones has been very rewarding. They are the good stuff for sure, and I covet more of them.

I would encourage you to document how you are arranging to get the custom large sizes. Someone may find it useful. I cannot completely rule out that that someone will be me.

You are correct to say that these are "not the most popular stones," but that's not because anyone has expressed the slightest dislike of them, anywhere I've seen. It's just that they're expensive and most have not tried them. I find them not unlike the Naniwa diamond stone line, but they come with more thickness.

 

[Chasingsharpness]

Indeed when I said they were not popular, I meant that they are rare. Everyone I know who has tried them has given great reviews. As far as the custom sizing, I have been told by Tosho that they can get a 290x100mm which I am happy with.

I just need to decide on the grit (800 or 1000.to start with, perhaps a higher or lower grit too like a 400 or 3000} and the hardness. The website says:
The Hakuto Series comes, in order from Hardest to Softest, as ‘1’, ‘1S’, ‘2’, ‘2S’, and ‘3’.
Alot of choice, I'm unsure how to discrimate them. Perhaps a 1 or 1S. I am mostly going to use this to sharpen large cleavers like CCK soft carbon or stainless, but want to leave my options open for the future as I'm considering having a custom made with a harder steel like magnacut.

 

[ethompson]

In general I think their recommendation has been that for higher grits and wider bevels with mono steel the softer you want the stone to be. For instance if doing bevel polishing on a honyaki yanagiba, at 3k or 6k you may start using a 2 or even 2s to keep the speed and feel nice. Personally I have the 1 all the way from 200-6k and don't feel like I'm missing anything. Though feedback is pretty low on my list of priorities for a synth and most of my experience comes from wide bevel work as opposed to edge sharpening.

Any of these stones will cut any steel - nice benefit of diamonds.

You really should just see if you can get their recommendation for a set with either a standard or progressive hardness. One of Tosho's founders, Ivan, who works as a sharpener in Japan now, probably has the most experience of anyone alive using these stones on knives and if you're ordering multiple what Im guess will be $500-600 stones (having looked extensively at the NSK lines / sizes in the past) I'd think he might work with the team at the store to chip in his thoughts.