Nagura

Re: Nagura

Dan Moening in Cooler, Breezy Sacramento

>I've always been told that nagura stones were a naturaling occuring chalk of some kind that is mined in Japan.

I did some googling about and most sites only have a few lines about the "stone", but tend to bear this out.

A few sites discussing Japanese blade making reference 2 types of Nagura Stone, used after each other due to the grain size. Here is one:

http://www.scnf.org/polish.html

Taken from another similiar site:

"Chu-nagura and Koma-nagura are taken from a same mountain but Koma-nagura is finer."

My opinion regarding the cutting action is that the higher grit stones take much too long to create an actual slurry before they may glaze over. The Nagura Stone must have a grain structure that is very close to the grit of this stone and is a "starter" slurry.

Whatever the reason, I find them to be a great addition.

Dan.

Re: Nagura

Jack Guzman

>I emailed Joel at Tools for Working Wood and Harrelson Stanley of HMS enterprises and these are the responses I got. I'm posting these now for the archive in case someone else asks the same question.

Hi Jack,

The Nagura is a stone that creates a slurry (paste) while working on the surface of the fine Japanese water stone. It creates a slightly finer abrading surface than the stone alone sense the abrasive particles are already used due to the action of the Nagura.

Regards,

Jeff Ratta

Operations manager

HMS Enterprises, Inc.

Jack,

> > a nagura stone is a "correcting" stone. it has two functions: the first

> > is more common with natural waterstones the second more usual. It is

> > used for correcting out of flat stones - where you don't need to flatten

> > the entire stone or you have one area with an impurity or in my case the

> > ends of the stone which wear less than the middle. It also creates

> > slurry - which on finer stones makes sharpening go faster (the entire

> > theory is too long to type in one email)

> > they stones are made I think of chaulk - waterstones are friable and

> > wet can give off slurry when rubbed with the much softer but dry nagura

> > stone. The nagura stone has very very soft particales which like chaulk

> > once wet melt into mud and do no sharpening - which is why they don't

> > continate things. They were more important when natural stones had small

> > impurities. I sometimes use one to even out wear and to create slurry by

> > rubbing just the ends.

> >

> > We used to stock a natural nagura but the mine closed. We now stock a

> > Norton nagura stone which is artificial.

> >

> > joel

> >

> >

> > --

> > Tools for Working Wood

Re: Nagura

Pam Niedermayer - Austin, TX

>So what's the article going to say? The two replies are contradictory.

Pam

Re: Nagura

Jack Guzman

>No article Pam. My last post was just a FYI.A report of the meagher responses I got.I'm surprised at how little information is available on the subject.I think I'll email Norton. Seein they make a synthetic nagura they must know a little more about it.At least I learned from Joel not to wet my nagura.I've been storing it in the pond with my stones.---Jack

Re: Nagura

Bill Lowrance in Geneva

>And: If they're so useful with water stones, why aren't (as far as I know) naguras used with oil stones?

Re: Nagura

ThomD

>I live pretty well with my nagura mostly in the box. I think it is essentially a deglazing tool. You sprinkle a little water on the stone, then you start sharpening. Darn! The stone glazes imediately, maybe because it wasn't wet enough. Whatever the reason, you rub it with the N, and the steel smear is gone, and you hope for the best. Or you forget about it, rub it with another stone, whatever. You can use sandpaper or scrubbing pads. For most work the contamination issue is a non-issue.

I don't buy any arguments that relate to mud. All mud performance is just clean stone performance. When the tool passes over the stone properly, the mud is knowhere to be seen in the wake. Could a small amount of mud get in the texture of the stone and add to the cutting. Maybe, but I see no real performance difference. N your stone, wash it clean and use it or leave the mud on, differences are largely imagination.

Why no oil stone Ns? Because, Norton aside, the two sides of the stone world don't talk or learn much from each other. More importantly, oilstones don't glaze as easily, because oil is really slick. And oil stones are really hard, and aren't easily cleaned with a piece of chalk. but you can unglaze them with other abrasives if need be.