this is actually what I see and which explains why with a single base stone and different nagura (assano for example) then a tomo you can go from start to finish without anything else.
But the question remains
Mohs Scale for testing the hardness of stones
- Thread starter alx gilmore
- Start date
But the question remains
"But to be simple, I put the "invisible hand" aside. Let's imagine that it is a robot with a constant gesture with a weak pressure as in the finishing step".
Nope, doesn’t work that way. It’s not the stones.
Tiger Woods could beat most any duffer on any course with a mixed set of thrift store golf clubs… So, how much difference does a brand name set of clubs make.
Same for Alex or anyone who knows their way around a Jnat.
“I suggest that with Jnats, it is the compositional balance of these two major oxides coupled with the other 8 major and 22 minor elements, that create and allow the character of the stone to cut certain steels not only more easily but with that elusive commodity of Grace.”
Yea, and pizza is just flower, water, and tomato sauce.
It’s a cocktail, it depends on what is in the glass and in what proportions. A Jnat, like any natural stone can vary from one side of the stone, to the other, as can the Nagura.
"If I understood Alex correctly, the specific sharpening capacity of the base stone would be linked to the high composition of SiO2 and Al2O3 AND the ability of it to continuously release abrasive particles in order to feed the sharpening fire and counterweight breakdown slurry and its loading in metal particles."
Honing razors is not just about sharpness. Sharp is easy, hone on diamonds.
"If I'm on the right track and haven't missed anything important, my personal conclusion and assumption (not a truth) is that the mud does all the sharpening work."
It’s a cocktail and your cocktail may/will be different from my cocktail. It’s the honer, not the stone.
"From this my question: what are the results by taking a bow and a nagura Jnats? With an Arc, When the mud has lost its sharpening force by its reduction and the pieces of metal, re-creating a mud would not allow the work to continue?"
If you are asking, can you use Jnat slurry on an Ark and get Jnat results?
NO.
Each Jnat, each Nagura will be different, they are natural stones, they contain what they contain.
A Tsushima slurry on an 8k will produce a Kazumi hazy bevel and less straight edge than a water honed 8k. Tsushima slurry on a SG20 will produce a mirror polish and not as keen an edge as water honed SG20 with not as bright a bevel. A Surgical Ark will produce a scratchy bevel and not as keen an edge, as water or oil honed edge.
Each of these results could change by changing the nagura.
If folks knew exactly why Jnats work and how they do, somebody would reproduce them in a synthetic form… but they have not. They have tried, nothing yet.
It is the synergy between different Nagura slurry and slurry from the base stone produce, that make it work. Different Nagura produce different results, experimentation can give you a Nagura progression, but still it come down to the skill and experience of the honer and the quality of the razor.
You can not even get Jnat experts to agree on the progression of Mikawa nagura, they are not graded by grit size, though there are some generalities.
Add to all the above, Hard Ark performance is dictated by stone face finish, you just added whole other set of variables.
You are talking about a single variable, that does not exist in a vacuum.
Nope, doesn’t work that way. It’s not the stones.
Tiger Woods could beat most any duffer on any course with a mixed set of thrift store golf clubs… So, how much difference does a brand name set of clubs make.
Same for Alex or anyone who knows their way around a Jnat.
“I suggest that with Jnats, it is the compositional balance of these two major oxides coupled with the other 8 major and 22 minor elements, that create and allow the character of the stone to cut certain steels not only more easily but with that elusive commodity of Grace.”
Yea, and pizza is just flower, water, and tomato sauce.
It’s a cocktail, it depends on what is in the glass and in what proportions. A Jnat, like any natural stone can vary from one side of the stone, to the other, as can the Nagura.
"If I understood Alex correctly, the specific sharpening capacity of the base stone would be linked to the high composition of SiO2 and Al2O3 AND the ability of it to continuously release abrasive particles in order to feed the sharpening fire and counterweight breakdown slurry and its loading in metal particles."
Honing razors is not just about sharpness. Sharp is easy, hone on diamonds.
"If I'm on the right track and haven't missed anything important, my personal conclusion and assumption (not a truth) is that the mud does all the sharpening work."
It’s a cocktail and your cocktail may/will be different from my cocktail. It’s the honer, not the stone.
"From this my question: what are the results by taking a bow and a nagura Jnats? With an Arc, When the mud has lost its sharpening force by its reduction and the pieces of metal, re-creating a mud would not allow the work to continue?"
If you are asking, can you use Jnat slurry on an Ark and get Jnat results?
NO.
Each Jnat, each Nagura will be different, they are natural stones, they contain what they contain.
A Tsushima slurry on an 8k will produce a Kazumi hazy bevel and less straight edge than a water honed 8k. Tsushima slurry on a SG20 will produce a mirror polish and not as keen an edge as water honed SG20 with not as bright a bevel. A Surgical Ark will produce a scratchy bevel and not as keen an edge, as water or oil honed edge.
Each of these results could change by changing the nagura.
If folks knew exactly why Jnats work and how they do, somebody would reproduce them in a synthetic form… but they have not. They have tried, nothing yet.
It is the synergy between different Nagura slurry and slurry from the base stone produce, that make it work. Different Nagura produce different results, experimentation can give you a Nagura progression, but still it come down to the skill and experience of the honer and the quality of the razor.
You can not even get Jnat experts to agree on the progression of Mikawa nagura, they are not graded by grit size, though there are some generalities.
Add to all the above, Hard Ark performance is dictated by stone face finish, you just added whole other set of variables.
You are talking about a single variable, that does not exist in a vacuum.
Oh I bet they can produce em. It's just not economically feasible.
Sintering ceramic hones probably takes enough pressure already... Making copycat natural stones would probably require force in the range of making synthetic diamonds... But instead of producing a mineral crystal a few mm across at most, you're producing a sizable, friable, heterogeneous block... So using explosives to produce the pressure is much more involved and way way way beyond cost prohibitive.
Sintering ceramic hones probably takes enough pressure already... Making copycat natural stones would probably require force in the range of making synthetic diamonds... But instead of producing a mineral crystal a few mm across at most, you're producing a sizable, friable, heterogeneous block... So using explosives to produce the pressure is much more involved and way way way beyond cost prohibitive.
It makes a very big difference, because 2 points on the Mohs scale is a lot, and silica is only marginally harder than hardened steel. Most of what makes natural stones seem special and different to synths is because of the way silica changes during the course of honing, and it's a particularly important element in razor honing to achieve very sharp but highly polished and refined edges.
I'm not quite sure I understand these q.s but... you can use Japanese nagura on an ark, you can use them on almost anything and they work quite nicely. But there may not be a massive amount of point, unless you only had one stone (an arkansas) and wanted to do a larger progression. If you re-create nagura mud on an ark it will continue cutting, but you're cutting pretty much exclusively on that slurry, not on the ark, until you clean it off at the end.
The majority of natural stones, including jnats, rely on an element of friability in order to cut, and continue cutting. Novaculites don't - they cut on surface condition and micro porosity. A translucent ark with an Atoma 140 surface is a very quick stone, with a 1200 surface it's painfully slow. And if you really want to see fast - leave an atoma created slurry on a trans ark and go on that.
The JNS synthetic Aoto are very popular polishing stones fwiw. Probably trash on a razor though.
Yea, nobody has made a synthetic Jnat yet. I remember back in the day when the SG20 hit the street, folks were calling it a Jnat killer, it would put Jnats out of business.
Not so much. It is a good stone, capable of producing sharp edges and polished bevels, but Jnat have only gotten more popular since the SG20 heyday.
There are some stones with ground up natural stone that produce interesting results, but still no Jnat quality and range.
For me the only thing that rivals a Jnat edge is an Ark, but they are very unique edges, produced very differently. They are not the same or better, they are different. Both are light years from an SG20.
There is no need to “bump up” and Ark.
Not so much. It is a good stone, capable of producing sharp edges and polished bevels, but Jnat have only gotten more popular since the SG20 heyday.
There are some stones with ground up natural stone that produce interesting results, but still no Jnat quality and range.
For me the only thing that rivals a Jnat edge is an Ark, but they are very unique edges, produced very differently. They are not the same or better, they are different. Both are light years from an SG20.
There is no need to “bump up” and Ark.
Indeed.
JNat is JNat like Coca-Cola is Coca-cola and McDonald's is McDonald's.
It is clear that if someone made synthetic JNat (JSynt) and managed to make an edge as well as JNat, he would be very badly received by lovers of natural stones and especially JNat lovers.
It would be a butcher's shop.
JNat is JNat like Coca-Cola is Coca-cola and McDonald's is McDonald's.
It is clear that if someone made synthetic JNat (JSynt) and managed to make an edge as well as JNat, he would be very badly received by lovers of natural stones and especially JNat lovers.
It would be a butcher's shop.
I doubt it. I think we JNat fans would treasure the natural stones for what they are, and respect the synthetic JNats. That's just how I feel about the SG20K, which makes a very impressive edge, and about hard arks, which make an even more impressive edge.
Gimme a tube of glue and a beach and I'll make you a better whetstone than any amakusa you can throw at me...
Sure, go for the low-hanging fruit. Now do an Ohira suita.Gimme a tube of glue and a beach and I'll make you a better whetstone than any amakusa you can throw at me...
Interesting subject. Very complex; hard to distill down to a simple answer. Alex's Moh's test is just a sort of field expedient way to test the hardness of the stone in terms of its friability. It's not actually testing the hardness (in strict terms) of the stone, and as another fellow said, simply isn't capable of that because the stones aren't homogeneous but composed of a mix of many different components.
Friability of materials can be difficult to test, due to their often being strong in one way but not in another. Test method can make a major difference in results. An extreme example I've seen cited to explain that difficulty is testing diamonds vs. rubber stoppers. If we put both in a test where they were rubbed on sandpaper, we would certainly find the diamonds far more resistant to wear/friability. However, if we put both in a test where they were struck with steel hammers, we'd find the rubber stoppers far more resistant to wear/friability. So the test method is very relevant to results and testing needs to (as best as possible) reflect the intended use.
I'm not entirely sure what would be a good test for friability - and certainly even more difficult would be a nondestructive test method. A crush test that measured pressure per unit of area might reflect well, but would destroy whatever was tested.
Friability of materials can be difficult to test, due to their often being strong in one way but not in another. Test method can make a major difference in results. An extreme example I've seen cited to explain that difficulty is testing diamonds vs. rubber stoppers. If we put both in a test where they were rubbed on sandpaper, we would certainly find the diamonds far more resistant to wear/friability. However, if we put both in a test where they were struck with steel hammers, we'd find the rubber stoppers far more resistant to wear/friability. So the test method is very relevant to results and testing needs to (as best as possible) reflect the intended use.
I'm not entirely sure what would be a good test for friability - and certainly even more difficult would be a nondestructive test method. A crush test that measured pressure per unit of area might reflect well, but would destroy whatever was tested.
Nice post. I've tried explaining these differences / nuances on KKF before, but I didn't manage it quite so clearly and cogently I don't think.
I've thought some more on this.
If we're talking about chemically identical rocks,
then I think the one with finer particles will be harder.
A lot of times, the ability of a glue to stick to other things
is stronger than the glues ability to hold together over distance.
For this reason some glue works better when mixed with a fine filler.
If we consider natural shale hones as being abrasive particles
with everything else in the rock as being binder,
then it makes sense to me that finer abrasives would be in the harder hone.
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