How do you evaluate a new JNAT?

[JPO]

How do you know if the stone you got is a quality stone?

Do you have any litmus tests to determine the limits and best use of your stone(s)?

I have a few JNAT's i would consider good finishers. However, as this JNAT rabbit hole gets deeper i am exploring stones stones in the upper mid/pre finishing range. I am looking for a work horse.

I guess others are also asking them self the question, is this a good stone, or is the problem just me.
After all, my biggest adversary in my life is shaving my face in the morning

I am getting a Wakasa LV 4.5 and a koppa sized Nakayama LV 5, in the lower price range. The koppa can always be cut to be used as naguras.
The shave test is really not that useful in this category/range, because i plan to use a dedicated finisher anyway.

I understand these stones needs to be figured out, and the steel might factor in. I was just interested in how you approach a new stone.

I do have a set of Asano Naguras i was hoping could be a better match with different stones. One of my finishers do not work that well with these naguras.

 

[lightfoot]

You could work an edge up to 5K and do two medium tomo or diamond slurries back to back (diluting each). While this won’t provide an exhaustive understanding you will have some kind of read on the base stones.
If I’m evaluating new stuff I’m just vibing with them and just getting acquainted. Not so much a concern with epic results…

 

[lightfoot]

Another thing I might do in an attempt to get an understanding of the base stone by itself is to do an initial lapping with 220 grit wet dry and hone on water only for a little while. Then I might try 400, 600, etc. I would just kind of make a mental note of the fingerprint it’s leaving on the bevel at every surface change. I think sometimes we get so caught up in slurry we forget to see with the based on itself is capable of.

 

[Calou]

Very interesting question because I have the impression that it will have as many answers as definition of the word Quality by their users.

My personal approach to knowing a new JNATs is the same as for other natural stones….and synthetic. Because ultimately it is a tool for working steel. The goal is still to produce the edge you like. Do not confuse the sensations of honing on a stone and the result on the edge. But you can ultimately choose a stone of lesser "quality" on steel but which provides a better feeling when using it...if you like honning (like me).

So my approach is to start from the goal but not from the means.
Apart from the questions of toxic inclusions, consistency, natural homogeneity, I do not expect the same from my stone to reframe a geometry, reset bevel, sharpening, finalize the edge. And for me, the grit is not necessarily the primary criterion. And for you, what do you expect as a result on your bevel and edge at these different stages?

The question of quality becomes more difficult if you use nagura in the honing technique because you have to take the interaction of the two stones into account.

In the end, with a new stone that I think a priori specializes in such a stage, I still test it on all stages with and without mud. It is after these tests that I have an overall view of the stone, of all its « qualities” and all its “faults”.

There are faster or more specific approaches, but you will know less about your stone.
With your microscope it will be much easier and faster

 

[JPO]

Another thing I might do in an attempt to get an understanding of the base stone by itself is to do an initial lapping with 220 grit wet dry and hone on water only for a little while. Then I might try 400, 600, etc. I would just kind of make a mental note of the fingerprint it’s leaving on the bevel at every surface change. I think sometimes we get so caught up in slurry we forget to see with the based on itself is capable of.

I have not found any JNAT's yet that are particularly good with water only. Playing with surface texture did not give me much with my other JNAT's. It does seem to effect coticules allot more.

I think i will start with a pure tomo slurry, generated from a hard one that more or less kick up the base stone.
Some stones respond really well with a more viscous slurry. As you hone, and the slurry changes consistency, sometimes some stones start to cut really fast.
It is not always easy to hit that sweet spot. Increased cutting always comes at a cost to the apex.
Part of what makes a good finishing stone for me is how well the stone handles different slurry densities.

I was never that intrigued by the 1k to dmt slurry honing. All my razors have their bevels set already, so as you say, the 5k range might be a nice place to start.

 

[luvmysuper]

How do you approach a new JNAT?​

• Be calm and gentle
• Avoid direct eye contact
• Keep a comfortable distance and respect the JNAT’s space
• Let the JNAT approach you first and let it sniff you.
• Avoid sudden movements which can be threatening.

 

[JPO]

Very interesting question because I have the impression that it will have as many answers as definition of the word Quality by their users.

My personal approach to knowing a new JNATs is the same as for other natural stones….and synthetic. Because ultimately it is a tool for working steel. The goal is still to produce the edge you like. Do not confuse the sensations of honing on a stone and the result on the edge. But you can ultimately choose a stone of lesser "quality" on steel but which provides a better feeling when using it...if you like honning (like me).

So my approach is to start from the goal but not from the means.
Apart from the questions of toxic inclusions, consistency, natural homogeneity, I do not expect the same from my stone to reframe a geometry, reset bevel, sharpening, finalize the edge. And for me, the grit is not necessarily the primary criterion. And for you, what do you expect as a result on your bevel and edge at these different stages?

The question of quality becomes more difficult if you use nagura in the honing technique because you have to take the interaction of the two stones into account.

In the end, with a new stone that I think a priori specializes in such a stage, I still test it on all stages with and without mud. It is after these tests that I have an overall view of the stone, of all its « qualities” and all its “faults”.

There are faster or more specific approaches, but you will know less about your stone.
With your microscope it will be much easier and faster

One of the most important qualities for me is the tactile feel of the stone. If that was not important to me I would just stick to synthetic stones. The stone does not need to be fast, but speed is a quality metric that will rank the stone in the right direction. So speed and tactile feel is one quality attribute, especially for stones in the mid to upper mid-range.

My Tsushima Nagura bench stone is one example of a stone with good feedback, but i do feel it is a little too slow. I will use it just to mix things up, but i do not feel it is a quality razor stone compared to other options. Good for woodworking tools though.

If there is impurities in the stone that produce deeper striations the stone will not be used for razors. If it is fast it can still be a grate knife stone. But in that case it would need to really rank high in the aforementioned characteristics. I will not spend allot of time "figuring" out the stone if this test fails. You can probably feel if something is "off" quite early.

I do agree that most stones, particularly natural stones need to be figured out with a specific goal in mind. However, i do feel some generalizations can be made about how you approach a JNAT compared to e.g. a coticule.

 

[JPO]

How do you approach a new JNAT?​

• Be calm and gentle
• Avoid direct eye contact
• Keep a comfortable distance and respect the JNAT’s space
• Let the JNAT approach you first and let it sniff you.
• Avoid sudden movements which can be threatening.

I am Norwegian. I am still learning the subtleties in the English language. Lost in translation as they say.

Let the JNAT force be with you, be one with the JNAT, and adhere to the listed precautionary measures that applies

 

[luvmysuper]

I am Norwegian. I am still learning the subtleties in the English language. Lost in translation as they say.

Let the JNAT force be with you, be one with the JNAT, and adhere to the listed precautionary measures that applies

My apologies! Just a poor attempt at humor.
The phrase "approach a JNAT" would imply a "meeting", so I used the advice one would receive if asking how to approach and meet a dog that you are not familiar with.

 

[JPO]

My apologies! Just a poor attempt at humor.
The phrase "approach a JNAT" would imply a "meeting", so I used the advice one would receive if asking how to approach and meet a dog that you are not familiar with.

Good one by the way
I guess it is too late for me to change the title of the thread. As a moderator can you change the title?

 

[luvmysuper]

Good one by the way
I guess it is too late for me to change the title of the thread. As a moderator can you change the title?

I believe you're asking about initial evaluation.

 

[lightfoot]

One of the challenges in evaluating a new stone is trying to define what we even mean by the term evaluation. There are very few if any meaningful data points to attempt to extrapolate because when it comes to this hobby everything is unverifiable and at the same time unfalsifiable.
That being said there may be members here that may in fact have put together a more meaningful set of evaluational standards than I have been able to come up with over the years.

 

[JPO]

One of the challenges in evaluating a new stone is trying to define what we even mean by the term evaluation. There are very few if any meaningful data points to attempt to extrapolate because when it comes to this hobby everything is unverifiable and at the same time unfalsifiable.
That being said there may be members here that may in fact have put together a more meaningful set of evaluational standards than I have been able to come up with over the years.

Understanding how these stones are prized might also be helpful. If i am paying a premium just for the visual characteristics of the stone and the name of the whole it was dug out of, it would be nice to know how this is weighed compared to the pure performance.
I guess this is just my western way of thinking

The stones i am getting is what i consider plain/ugly stones. It will be interesting to compare them to what is considered collectors grade.

 

[RayClem]

Synthetic hones are fairly predictable as they are made in a factory using a recipe for grit size, abrasive type, binder type, density, etc. Thus, the experiences of others are very useful in helping you learn how to use such hones. On the other hand every natural stone is one of a kind. Thus, unless you are purchasing the natural stone from someone who has actually used it to hone razors, you are going to have to figure out the best way to use the stone in your setup. Because there are so many different types of Japanese Naturals, they might have the steepest learning curve of all natural hones.

I would suggest you start by using one of your least expensive razors. If you do not already have something on the order of a Gold Dollar razor, you might want to procure one for experimentation.

If you do not already have a good jewelers loupe or USB microscope, I would suggest you get one. When learning to use a new hone, these tools will help you understand what is happening to the bevel.

There is a YouTube channel called TheJapanStone. Although many of the videos are rather old, they show how to use a variety of Japanese Natural stones for razor honing. They also show what to look for in an enlarged image of the razor edge. Hopefully, you will find some of the videos useful.

 

[JPO]

Synthetic hones are fairly predictable as they are made in a factory using a recipe for grit size, abrasive type, binder type, density, etc. Thus, the experiences of others are very useful in helping you learn how to use such hones. On the other hand every natural stone is one of a kind. Thus, unless you are purchasing the natural stone from someone who has actually used it to hone razors, you are going to have to figure out the best way to use the stone in your setup. Because there are so many different types of Japanese Naturals, they might have the steepest learning curve of all natural hones.

I would suggest you start by using one of your least expensive razors. If you do not already have something on the order of a Gold Dollar razor, you might want to procure one for experimentation.

If you do not already have a good jewelers loupe or USB microscope, I would suggest you get one. When learning to use a new hone, these tools will help you understand what is happening to the bevel.

There is a YouTube channel called TheJapanStone. Although many of the videos are rather old, they show how to use a variety of Japanese Natural stones for razor honing. They also show what to look for in an enlarged image of the razor edge. Hopefully, you will find some of the videos useful.

I understand.

Part of the reason i started this thread was just to get an idea of how people evaluate a JNAT to answer the question, is this a good stone, and for what use case.
They are all different, but there are also allot of common denominators.
If you were lucky enough to try 100 JNAT's, and you could only keep a few, what would you keep, and why?

 

[cotedupy]

How do you approach a new JNAT?​

• Be calm and gentle
• Avoid direct eye contact
• Keep a comfortable distance and respect the JNAT’s space
• Let the JNAT approach you first and let it sniff you.
• Avoid sudden movements which can be threatening.

Ha! Excellent.

 

[cotedupy]

I test all new stones, Japanese or otherwise, in exactly the same way initially. And I think there's a good case for always using the same thing that you know quite well.

In my case I use a san mai Aogami 2 Tosa knife that I've taken down to a very slender zero bevel / 'Scandi grind' - it's probably actually at or below that of a razor. But I find knife testing is an easier way to more accurately judge the speed of a stone, it allows me look at polishing potential, and I can still get a pretty accurate estimation of whether the stone will be better for knives or straights.

If I think it's the former then all's good because I've already tried on a knife. But if it's going to be better for razors; then I take one I know well and use the stone from a worn atoma 400 slurry, diluted to finishing clean. I'm hoping to erase the previous finish and get an accurate impression of the stone itself without using other nagura or slurry, even if in normal use in the future I will be using them.

---

That's just me though! I basically just try to cut down as many extraneous variables as possible.

 

[lightfoot]

I understand.

Part of the reason i started this thread was just to get an idea of how people evaluate a JNAT to answer the question, is this a good stone, and for what use case.
They are all different, but there are also allot of common denominators.
If you were lucky enough to try 100 JNAT's, and you could only keep a few, what would you keep, and why?

I gravitate towards a high density of abrasive content in the base stone if possible. I know some of the super hard stones can have limited cutting ability but make a good platform for Nagura for that very reason. But it’s nice to have both available if possible.
Sometimes I wonder why there are stones that are problematic with water only and why that’s the case. I have a couple that can get into the clear mirror with prolonged use on water while others show clear bevel degradation in much less time. It seems that the few that I have that are great on water have a higher abrasive density or concentration but there’s no way to really prove that…

 

[cotedupy]

If you were lucky enough to try 100 JNAT's, and you could only keep a few, what would you keep, and why?

Go on then... I'll play. I haven't tried 100 jnats I don't think, but maybe 50 or so, here are three I'd keep:


A softer, finer Tanaka Aoto. Because they're a pleasure to use, leave good edges, and highlight banding extremely well in a progression.

Maruoyama Shiro Suita. Because it's just such a superb kasumi stone, and works well for yanagi and prefinishing razors.

Nakayama finishing stone. Because there's something special about Nakayama; both the feel, and because good examples are one of the few jnats I would consider 'fast' for their level.


(And if I can add a fourth that I've never actually tried - a Mikawa Nagura benchstone.)

 

[Frank Shaves]

then I take one I know well and use the stone from a worn atoma 400 slurry, diluted to finishing clean. I'm hoping to erase the previous finish and get an accurate impression of the stone itself without using other nagura or slurry, even if in normal use in the future I will be using them.

---

That's just me though! I basically just try to cut down as many extraneous variables as possible.

I like the idea of raising slurry with a worn diamond plate to understand the stone. I use a worn DMT 3 inch fine (red) plate - costs less than 15 USD.