Thread: The new High Carbon Glass stones are excellent

Originally Posted by ZethLent

FYI, I have no desire to buy and use the GS stones, I am happy with the Naniwa Chosera's and J-nat that I currently use. But I am interested in the Gokumyo stones that are also made in Japan, but by Suehiro. But these are only available in #10000 #15000 and #20000 and cost a pretty penny too.

Oh come on, Seth! It's just 75,000 for the set!

Originally Posted by JimR

Oh come on, Seth! It's just 75,000 for the set!

Well, I got excited when I looked at the link but was less so when I did the yen to dollar conversion and got $928!
Maybe not this week.

Originally Posted by JimR

Oh come on, Seth! It's just 75,000 for the set!

Ha Ha Ha... Well it is about what I paid for my current set up of three hones, my finisher bearing the majority of that cost. And it's only 1/3 what I reccently paid for my new set of GHB, and that is where time and money are being directed right now so it's a NG for the time being.

In comparison to j-nats they are quite nicely priced. But in comaprison to other ceramics, they are in another echelon. I have been told though that they aren't as hard/slick as the GS stones and aren't as soft as the Naniwa's. They are reputed to not change shape when soaked as some of the Naniwa's will do from time to time. And in the write-up it says they are quite heat resistant too.

Hi Zeth,


I once was able to try the Gukomyo 20k for several days and razors.
I tried it for Razors as well as kitchen knives and wrote some of my experiences down in the Knifeforums:
20000 grit stone anyone? - Knifeforums.com - Intelligent Discussion for the Knife Enthusiast - Powered by FusionBB

I found the 20k to be comparable in hardnes and feel to the Chosera line.
And btw. they are in fact available at other grit ranges, but still cost a fortune:
http://www.suehiro-toishi.com/gokumyo/gmseries.html

Meybe that will help you.


Regarding the Shapton GS white vs grey, I don´t really see a big difference.
I own the 1k (white), 4k, 6k, 8k (all grey) and 16k and 30k (white again) and am having no difficulties with inconsistencies.
I don´t believe anybody would have difficulties using the whole set in white, either.

Manufacturers sometimes have funny ways of examining and rating their products.
I have no Idea why a Shapton 16k would be not considered for razors.
But to give Shapton credit, I don´t think they would call it a no-no,
they just don´t recommend it wich means, they haven´t tested it.
Usually manufacturers will only recommend soemthing, if they have tested it and are 100% sure it works.
Otherwise they tend to say "don´t do it, we haven´t tested it so it could go wrong"

I will have to very respectably disagree with you on some points, I read your review on the 20k stone and I think some of your opinions are maybe a bit flawed. For example why would shapton a very reputable stone manufacturer not test their stones on razors? Even if they didn't the edge that the stones they produce isn't vastly different from the edge on a knife or axe, the method for sharpening is.

I have also tried explaining several times that a grit rating while useful isn't that important when it comes to the edge produced, for example everyone knows that garnets in coticules are pretty big compared to other stones that achieve a similar effect on steel. Also the so called scratch pattern is flawed in terms of how sharp the object is, for example if I were to use a knife and cut the steel it would leave a perfectly smooth bevel, no scratches at all, yet the edge might not be as good as say the edge off a JNAT which leaves a pretty harsh scratch pattern but the depth of the scratches is pretty shallow and also the serrations on the edge are different giving a different cutting effect.

So I just had a few free minutes and thought I'd call up Shapton and find out what they had to say. I spoke to a guy named Nakai (may.

Apparently, the recommendations are based on the idea that the 30000 is the finisher, and everything else is decided on how much time it takes to move up in that progression. Thus, the jump from 10000 to 30000 is not so high, and the jump from 3000 to 10000 is not so high, and that's your progression. They (not too surprisingly for Japanese honing) think that anything less than 3K is too rough for a razor, and an 8K is not fine enough for a finish for a razor, and the jump between 8K and 30K is too big. He didn't even mention 16K, but it was clear--the 30K is their finisher.

He also mentioned that, if you WERE to use the 8K, he recommended the HC version, as although the grit size is the same as the other stones they tend to be less exposed and thus leave a finer finish. (Not clear how that works, but that's what he said.)

As a closer, he told me I should call Harrelson Stanley at HMS enterprises, saying the guy knows more than anyone about Shapton stones...but I got some good Japanese practice, anyway.

I dont have the HC stones but I do have the 1/4/8/16k white ceramic on glass stones and they really are excellent.

I love the finish from the Naniwa stones but I do find they load up quite fast and dish pretty easily. The Shaptons are more aggressive cutters so you have to be more careful with them, but they are very hard wearing and put a killer edge on a razor.

Hi Memorael

no offense taken, non at all
I hear what you say about the scratch pattern and the shaving quality. I do not get tired to point out well enough that these two hardly have anything in common. I just prefer a tidy polish AND a good level of sharpness.
Like I mentioned, the 20k as well as the GS30k or a Nakayama produces a very nice, smooth edge.
If it didn´t, the stone was crap.
But at that expense I want the edge to be smooth, and well polished.


What I meant with Shapton didn´t test it, is probably they didn´t test it officially.
Let me give an example. I used to work for a company that makes surface technologies for corrosion protection.
They invented a product that can be applied to a steel surface to protect it.
The lawyers of our company said we were not to say it works on any steel
but only on these types we tried and have actual proof it works.
This includes many test runs wich are time consuming.
So we went on saying it works only for these we tried it on.

The thing is you never know if it *really* works the way you want it.
If it doesn´t (ie the edge of a razor is not shavable) but you said it works,
you can get sued yur pants off.
That´s why I thought maybe shapton didn´t go all the way with the gs 16k
and examining the edges produced on most razor steels,
but only for their high level 30k.

But that´s only an assumption, and to be honest Jims explaination is even better.
They want to market their 30k as an ultimate finisher (wich in my opinion it is ) and not te 16k

Awesome that makes perfect sense, I have a funny story about my stones. A couple of months ago I was getting pretty tired of having to soak stones and then put them away and what not that I was like ok screw it, and ended up buying a bucket and putting ALL my stones in there including some choceras, SS and other magnesia based stones and what not... I am actually thinking about throwing in my naturals too which are inexpensive of course. Anyway up to today I have had no problems whatsoever with cracking or melting away or any other bad thing that could happen to my stones, the cool thing is they actually take on a whole different set of characteristics some became softer and some I can't really prove but I think became harder but the cool part at least for me is they all behave differently and in my opinion I like them better like that.

The educational part is most of these stones are not meant to be soaked indefinitely which I think is similar to your explanation about the 16k not tested officially. One other thing, I am having a hard time finding a better finishing stone than the SS10k (in terms of more balance than other stones) I get the best mirror finish, the sharpest edge and overall the best ease of use. Some other stones leave a better edge but the polish lacks and I can't find a better mirror finish than SS10k. Well I hope you guys get the point. Thanks for reading!!!

I highly doubt that the 16000 is 'untested'. Look at the pdf of the glass hones (BEWARE this is a 36 MB download for slower internet connections it might take quite a while to download). Even though it is in Japanese you can see the pics of the edge after it has been honed on each hone. There are also 3D images of the scratch pattern on the bevel left by some of the hones. The blade in all of the photos is a razor made of Swedish steel.

The pentagon graph that accompanies each photo describes the five characteristics being tested. Starting at the top (and moving clockwise) of the pentagon is Feedback, Matrix Strength, Resistance, Hardness of Abrasive, Abrasive Grain Distribution.

I also had translated the descriptions of the 1~5 for each element on the pentagon graph but I cannot seem to find it. I am pretty sure that the hones are all tested equally.

The apparent difference in the #16000 over the #10000 and the #30000 is the lower number for grain distribution. Maybe that is all that sets it at the lesser categorization for razors...

It is also possible that the person doing the honing test for each hone is not using light pressure and has therefore made the #16000 the lesser categorization from heavy handed honing. This is just speculation on my part though.