Thread: Jnat Finishers

I have missed why hardness is considered to be such a particularly important characteristic for razor sharpening?

Originally Posted by jgjgjg

I have missed why hardness is considered to be such a particularly important characteristic for razor sharpening?

Jnats are fine. All of them are very fine. If they are soft, they shred particles easily, and the surface of the stone does not get burnished, ie. the sharp corners of particles on its surface do not get flatter-rounder. This slurry cuts faster, but leaves a less fine edge. Since we are talking about razor honing, the above are not desirable on finishers.

Its just the nature of the beast... While hardness generally means finer with jnats its not always true. There is hardness and there is fineness These are two different things.

A hard stone will generally produce a fine surface. most soft stones break away the surface before the surface can be fully refined. Most hard stones, due to the slow wear produce a fine, refined surface.

If you can find a stone that is super fine and not super hard it can still produce a nice edge providing it doesn't release too much slurry.

+1. BUT there are many stones that can produce great edges that may not be considered for finishing. For example some asagi or kiita stones are rated as finishers when they are actually softer than some suita stones. And why is a coticule considered a finisher then? The edges off my cotis(I have 3) are very soft yet sharp, although they don't approach the sharpness I get from my suitas. Not knocking cotis now, just saying. And hht root in or out from a suita isn't an indication of the blades ability to cut hair then? I know not everyone uses the hht but I do and compare always to what I get off my stones. So I would rate my sharpness off my suita at a 10 out of 10. Is my asagi or ozuku edge sharper? NO imo. And hardness is important as Vasili said regarding release of particles, yet my suitas don't release particles. So its a slippery slope. My dark blue Escher is also not in the range of my suita in terms of sharp either.

Originally Posted by bill3152

+1. BUT there are many stones that can produce great edges that may not be considered for finishing.
Other factors at play here too, the razor, the honer.
For example some asagi or kiita stones are rated as finishers when they are actually softer than some suita stones.
This is why So from Japan Tool has only sold a handful of Kiita in all his years of supplying stones.
And why is a coticule considered a finisher then? The edges off my cotis(I have 3) are very soft yet sharp, although they don't approach the sharpness I get from my suitas. Not knocking cotis now, just saying.
You've answered your own question Coti edges are generally comfortable.
And hht root in or out from a suita isn't an indication of the blades ability to cut hair then? I know not everyone uses the hht but I do and compare always to what I get off my stones. So I would rate my sharpness off my suita at a 10 out of 10. Is my asagi or ozuku edge sharper? NO imo.
You can pass HHT very early in the progression so it does not make a finisher. It just shows sharpness.
And hardness is important as Vasili said regarding release of particles, yet my suitas don't release particles. So its a slippery slope.
You obviously have exceptionally hard, fine Suita. This, however, does not categorise all Suita as razor hones, hence, as I said before, they are not generally sold as such.
My dark blue Escher is also not in the range of my suita in terms of sharp either.
Bill, I think you're missing the point. Sharp comes long before finishing stage which is more about comfort.

...........

Thanks, that's great insight!

That has been an interesting discussion so far - thanks !

But I'd like to come back to my original question:

Originally Posted by jollo74

Are specific kanji for Oozuku, Okudo and Ohira? Or some kanji that labels a hone to be suitable for kamisori?

And if yes, could you post them here?

Any pointers here?

Thanks
Jörg

oozuku 大突
shobu (shobudani) 菖蒲
oohira 大平
I don't remember how you write okudo, and, in the end of the ohira and ozuku you can ad the word yama, means mountain.
There are no labels that specify if a hone is suitable for kamisori. Those stones were quarried and cut for woodworkers, not barbers. And, there is no maruka stamp for those mines.
It is very possible that, if your friend finds a seller, he will see some stones with stamps. Almost none to none of them are worth anything, and are not guarantee for their performance. Stamps are easy to get there.
Basically, you want a hard stone, without inclusions, on the top or sides of the stone. The small cracks are not a problem if they are sealed. I bet I forgot to mention something, but keep those in mind, and good luck.

Razor hones are usually cut approx 5"x3", sometimes smaller. As above stamps often mean nothing & can be added at the whim of the seller.
Choosing a Jnat is not like buying a 30k stone . There are no guarantees other than what the seller gives you.

Indeed!

Just for the record, Okudo 奥殿 (Okudo-no)

Kindest regards