Thread: What is Grit in Japanese Natural Stones, and How Important Is It.

Originally Posted by SharpMan

Ok things just got more difficult. Which pictures are you referring to
when you said the scratch pattern from a coticule is much finer than
that of a shapton 30K?

I was under the impression that CrOx 0.5 micron was the same size
as the 30k Shapton particles.Vasilis where do you read that the scratches
left are 0.49 micron?

Sharpman

Regarding this post, I don't remember where I read about the 0.49 micron scratches, but I do remember that it was a reliable person and kind of makes sense. Looking at the photos of scratches from a coticule and this 30k shapton, it doesn't really looks like its somewhere near 30k. Most of the people who have one say that they are excellent for shaving, so I don't know what's going on. And, yes, the CrOx 0.5 micron and the 0.49 micron particles of the Shapton should leave comparable edges. I would like to know your opinion, if you have one Shapton 30k how fine is it compared to the CrOx.

I may be an idiot for thinking this, but if Japan and Oregon were joined at one time wouldn't it have the same basic geology?
Has anyone ever checked out the rock from Oregon? Is that to far fetched?

Originally Posted by Wintchase

I may be an idiot for thinking this, but if Japan and Oregon were joined at one time wouldn't it have the same basic geology?
Has anyone ever checked out the rock from Oregon? Is that to far fetched?

Correct me if I'm wrong, but I believe that the origins of these fantastic Japanese stones was a volcanic event, so it would depend on whether the event occurred while the two landmasses were still joined or not. I'm thinking that this occurred after they already separated.

Given that though, Oregon does have some volcanic activity, so it's possible that at some point in the past a volcano in Oregon threw up some similar materials, and they just need to be found and mined...

Anyone from Oregon want to start searching?

The world is full of hones. The Japanese ones are just the most famous. And, it's not just volcanic activity. Under there, there should be the correct conditions, temperatures, pressure, for the rocks to become hones, and must find them the right moment, when they have the best characteristics. In 100000 years from now if humankind still exists, they might be able to use the sand of Sahara to strop their razors. And this sand, I don't know, 1mil years ago? could have been rocks, and those rocks might have been excellent sharpening stones. In the history of earth, hones come and go. Today's cheap slate tiles, in 5000 years might become the finest hone ever existed, and our descendants (is this the right word?) might pay in their currency, 1000$ for a 5x2" piece.

Everything on the earth gets recycled. All the rock is weathered and then washed into the seas and then gets re-manufactured into rock again and the cycle goes on and on. What makes some rocks different is just happenstance. The right combination of minerals under the right conditions. I remember years ago during a geology Field trip going to Franklin, N.J which is a very famous locality for a vast assemblage of fluorescent minerals and had a variety of iron, manganese and Zinc Minerals. It sits on a hill and you can look across a broad valley to a ridge across which is Stirling Hill and both locations have these minerals. Most of the economically valuable ore went between the two and it was all weathered away leaving these two "tiny" legs left over.

I am looking for 2 straight razor users to come to Sonoma for a honing session to act as independent participants. I believe that I can prove that the grit from Japanese tennen toishi is as fine or finer than a Shapton 30k stone.
I will provide a 600x microscope for all of us to use, I have a Shapton 30k on glass stone, of course a few stones to play with, and lunch.

It would be helpful is one of the users has a video camera, HD prefered and knows how to use it, and a seperate Shapton 30k. If those fellows or gals who can come do not have either of those items, maybe they can borrow, beg or steal the items.
Professional sharpeners welcome as well as observers. I have a dedicate shop.

In the past a few of you have been to my shop and you know I love to sharpen for hours and hours and hours. So those who can come be prepared to spend the better part of a day here.

Because I am self employed almost any day of the week will work although Sundays - Thursdays are best.
No reason not to communicate through this thread. best wishes, Alex

It would be very interesting to see the results of this honing session! With text and hd video even better there a lot of people on here interested in j-nats and how to use them.

Originally Posted by alx

I am looking for 2 straight razor users to come to Sonoma for a honing session to act as independent participants. I believe that I can prove that the grit from Japanese tennen toishi is as fine or finer than a Shapton 30k stone.
I will provide a 600x microscope for all of us to use, I have a Shapton 30k on glass stone, of course a few stones to play with, and lunch.

It would be helpful is one of the users has a video camera, HD prefered and knows how to use it, and a seperate Shapton 30k. If those fellows or gals who can come do not have either of those items, maybe they can borrow, beg or steal the items.
Professional sharpeners welcome as well as observers. I have a dedicate shop.

In the past a few of you have been to my shop and you know I love to sharpen for hours and hours and hours. So those who can come be prepared to spend the better part of a day here.

Because I am self employed almost any day of the week will work although Sundays - Thursdays are best.
No reason not to communicate through this thread. best wishes, Alex

Did you find 2 candidates for this honing session?
I was reading that not to many razors can take the edge from sharpton 30k, any experienced with that?
perhaps its different with j-nats to get to the 30k range but nevertheless the article im talking about claims that
many razors collapsed meaning the edge off the sharpton 30k.

The original photos I took for my website about 5 years ago were not very good quality and they were in my opinion flawed in that the scratch patterns photographed on the blades were made with a slurried stone. All the stones I tested including the Shapton stones had a slurry generated with the same diamomd plate. I now think that the granuals in the slurry reflected the grit of the diamond plate rather than the stones intrinsic grit particle size. The same is true I believe of the actual surface of the diamond conditioned stone itself, there must be grooves left on the stone that more represent the diamond plates action rather than the stones intrinsic grit.

It is for this reason that the popular polishing techniques of the razor hone users here are encouraged to "polish their stones" to a mirror like shine that reflects a perfect image when held at a low angle. When a high quality tennen toishi is polished with a tomo or hon nagura the surface will become smoother without a doubt, and a harder stone will achieve a higher polish by definition. If a stone has a high polish working surface, this granular polish will effect the steel being applied in a likewise hard polished manner, simple physics.

Likewise if that same stone has a rough surface, the roughness will more agressively abrade the steel.

As I believe Stefan suggests and it is a good one, any tests would benifit by the: any slurry made up using a hon-nagura (a portion of the base stone). And I feel that any tests done without a slurry should be done with polished host stones Natural or Synthetic, with equally prepared surfaces. Alx

Originally Posted by Vasilis

Regarding this post, I don't remember where I read about the 0.49 micron scratches, but I do remember that it was a reliable person and kind of makes sense. Looking at the photos of scratches from a coticule and this 30k shapton, it doesn't really looks like its somewhere near 30k. Most of the people who have one say that they are excellent for shaving, so I don't know what's going on. And, yes, the CrOx 0.5 micron and the 0.49 micron particles of the Shapton should leave comparable edges. I would like to know your opinion, if you have one Shapton 30k how fine is it compared to the CrOx.