Thread: Nagura Pr0n...

After reading a reccent post on Jim's blog the Eastern Smooth about his full honing progression and the inclusion and use of nagura stones I decided to get a taste of the same, having easy access to these stones.

I have just placed an order for three nagura. I ordered a Koma, a mejiro and a botan.

A point I don't think Jim has made in his posts about nagura is that they are graded by name, but they are also divided in to four catagories within each grade. This extra labeling indicates the colour and shape of the nagura. Jim posted his nagura two of which are called 'Betsu jou' (別上) these are designated a white colour and an odd shape. The next is 'Bestu dai jou' (別大上), these are also white but are a uniform square shape. The next 'tokkyuu' (特級) has a striped appearance and is an odd shape. The last is 'Jou tokkyuu' (上特級) which is striped and a square shape. The divisions are not to designate a level of quality or fineness, but only denote scarcity.

I should also mention that I have seen nagura that have been stamped with a 'for razor use' instead of the above mentioned four divisions. And I have seen a stamped 'Iwasaki' nagura, although I don't know how authentic such a stone might be.

Here are each of the three that I bought, as advertised on the site I bought them from. They are all designated Tokkyuu nagura.

Koma:



Mejiro:



Botan:




I will also post some details of my own trial and I would assume errors when I have had success.

Check out this piece of koma priced at 76,860 yen. And it isn't even one of the 'scarce' striped ones...

This is really great stuff.

I have been playing with a nagura stone from Japanese Woodworker and a Coticule rubbing stone on my Coticule, Escher, Asagi, Kiita and a Chinese 12K going from a heavy slurry to a light slurry and then just water for a while now.

Can't wait to hear the techniques you guys use and the results with the different types of razors.

Thanks!!

Lynn

So I don't understand.

Do these stones make a slurry from the stone you use them on, or do they break down themselves to create the slurry? Or does it depend on the stone you are using them on?

I use a diamond plate on my Asagi if I want to create a slurry. To be frank, I doubt there would be a nagura hard enough to work up an asagi slurry on my stone - the best I would get would be the nagura slurrying itself, and what's the point of that?

James.

Originally Posted by Jimbo

So I don't understand.

Do these stones make a slurry from the stone you use them on, or do they break down themselves to create the slurry? Or does it depend on the stone you are using them on?

I use a diamond plate on my Asagi if I want to create a slurry. To be frank, I doubt there would be a nagura hard enough to work up an asagi slurry on my stone - the best I would get would be the nagura slurrying itself, and what's the point of that?

James.

Please forgive the new guy if I make a mistake here, but my understanding is that - like you said - you would work up a nagura slurry on the asagi and hone with that. But you go through a progression of, say, 3 naguras, e.g., from 'coarser' (Botan or Teijou) to 'finer' (Mejiro) to 'finest' (Koma), and then finish with a slurry created directly on the asagi with somethng like a diamond plate.

Or something like that....

Originally Posted by Woodash

Please forgive the new guy if I make a mistake here, but my understanding is that - like you said - you would work up a nagura slurry on the asagi and hone with that. But you go through a progression of, say, 3 naguras, e.g., from 'coarser' (Botan or Teijou) to 'finer' (Mejiro) to 'finest' (Koma), and then finish with a slurry created directly on the asagi with somethng like a diamond plate.

Or something like that....

Yep, pretty much that. Except that Tenjou is closer to Mejiro in fineness.

My only experiment so far,
1k bevel set, then Mejiro nagura on C12k (works on my Asagi too) then Asagi finish, worked great, and pretty fast.
I'll take some pics of the naguras and post tomorrow.
Now I have Koma nagura too but have not have time to play with it yet.
I can't use the nagura method on my Kiita because its of similar hardness as the nagura and I get mix of both stones in the slurry.

I see. So these naguras, where do they fit in the progression? You create the bevel using your usual stone, then hit the naguras? Do they kick in around the Norton 4/8 mark? Higher?

James.

James,
as far s I am aware there is coarse naguras that can be used for bevel setting too.


Here an interesting quote posted by Telly:

The true Mikawa Shiro Nagura stone is mined from the 12 layers of the Miwamura mountain in the Aichi prefecture. The four famous and most usable strata are Botan, Tenjo, Mejiro, and Koma.

Koma: The finest particles; used for JP swords.
Mejiro: Very fine; prepares edge for final finishing stage; the best for razors
Tenjo: Intermediate grit; mean for light repairs; white ones are soft and fast while ones with layers (usually yellow) are hard and slow
Botan: coarsest and fastest; meant for major repairs

Dr. Kosuke Iwasaki, Mr. Shigeyoshi Iwaski's father, believed that you could use different nagura in different stages of the honing process on the same Nakayama stone. This would allow you to progress from a dull edge to a shave ready edge without the need for other stones. However, to gain the most out your J-nat, he believed that your final nagura wasn't a nagura at all but a tomonagura.

Tomo = same
Nagura = slurry stone

It means a slurry stone that is identical to your finishing stone. If your stone is a Nakayama Kiita, then you would use a small piece of a Nakayama Kiita as your tomonagura. If your stone is an Ozuku Asagi, then you would use a small piece of an Ozuku Asagi as your tomonagura. It doesn't have to be a piece broken off of your whetstone but it should have similar characteristics.

Since most of us don't have a smaller yet identical piece of our Japanese whetstones, then a diamond plate is recommended. The diamond plate works because it's harder than the whetstone. It will build a slurry made up entirely of particles from your finishing stone. Instead of the slurry of an 8K nagura, you're getting the slurry of a 20K+ whetstone. Those particles break down and get smaller and finer, which will refine your razor's edge far beyond the purported grit of the stone. Only experience will tell you how many times you must repeat the process of building and diluting the slurry.

The Mejiro nagura is softer than the whetstone. It will break down and create a slurry of its particles, which are much coarser than those of your whetstone. As those particles break down, they can help bridge the gap from your intermediate finishing whetstone (Coticule, Shapton 16K, Shapton Pro 12K/15K, etc.) to your final finishing whetstone (Nakayama, Ozuku, etc.). However, they will never be as fine as the particles of your whetstone or tomonagura. That means there's a level of edge refinement that you will never reach.

I just did a nagura only progression on my new finishing hone last night.

The three nagura I posted about above are what I used.

I started with a DMT extra fine to set the bevel. I then did a slurry on my hard finisher with the Botan and cleaned up the scratch markes from the DMT. I rinsed the hone and the razor and did a Mejiro slurry and later rinsed and did a Koma slurry.

My final finish was the finishing hone slurry created by the DMT and the edge was so fine and so smooth I was in shaving heaven.



For those of you who think that the nagura being the same or near hardness as your substrate finishing hone I don't think it should be an issue if some of the finisher particles end up in the slurry. The worry should be unrinsed larger particles as you are moving up the progression.


I plan on repeating my test run on many more razors as the edge was as good as I get on my other Japanese natural.