Thread: A theoretical discussion about honing particles

Originally Posted by Wildtim

Bart, you are a little confused.

That's true for sure. Hence my desire to get into this swamp of particles.

Originally Posted by Wildtim

Thats why a Norton is faster than a Sun Tiger hone, they probably use exactly the same medium just in far different proportions.

A valid point for sure, but wouldn't the Norton actually cut more aggressively as well, in that case.
If it contains more particles, it probably releases fresh particles at a higher ratio too. And we all know that fresh sandpaper leaves deeper scratches than used sandpaper.

In addition to the grit designation discussion, sifting particles may be the starting point in the production of synthetic hones, but of course that's not the fact with natural hones. Only a few days ago, Rob Celis of Ardennes Coticule wrote in a thread that the Belgian Blue approximately contains 4000 garnets per inch² and the Coticule 8000 garnets per inch². Although he suggested as well that the grit rating of Belgian Naturals is also inspired by product orientation on a market that's dominated by grit/mesh numbers. (I can hardly blame them for that).

My point is merely that I feel people are far to often focussed on the grit numbers, a bit like everyone seems focussed on "Watt" when buying new speakers and on Megapixels when buying a new camera. Nothing wrong with that for the avarage honer/listener/photographer, but we're in the advanced honing section, so why not get carried away a bit?

Best regards,
Bart.

Originally Posted by Bart

That's true for sure. Hence my desire to get into this swamp of particles.



A valid point for sure, but wouldn't the Norton actually cut more aggressively as well, in that case.
If it contains more particles, it probably releases fresh particles at a higher ratio too. And we all know that fresh sandpaper leaves deeper scratches than used sandpaper.

In addition to the grit designation discussion, sifting particles may be the starting point in the production of synthetic hones, but of course that's not the fact with natural hones. Only a few days ago, Rob Celis of Ardennes Coticule wrote in a thread that the Belgian Blue approximately contains 4000 garnets per inch² and the Coticule 8000 garnets per inch². Although he suggested as well that the grit rating of Belgian Naturals is also inspired by product orientation on a market that's dominated by grit/mesh numbers. (I can hardly blame them for that).

My point is merely that I feel people are far to often focussed on the grit numbers, a bit like everyone seems focussed on "Watt" when buying new speakers and on Megapixels when buying a new camera. Nothing wrong with that for the avarage honer/listener/photographer, but we're in the advanced honing section, so why not get carried away a bit?

Best regards,
Bart.

Exactly... I love this stuff. Just wish I was smart enough to actually contribute! Ah, well... consider me your captive audience!

Originally Posted by FloorPizza

Exactly... I love this stuff. Just wish I was smart enough to actually contribute! Ah, well... consider me your captive audience!

Yeah I'm with you It is way over my head but I love it too. I may even learn something before it is over. It is sort of like the light in the kitchen, I don't need to understand nuclear physics to be able to flip the switch and turn it on. So I don't need to know this to hone my razors. OTOH, I do enjoy reading it and as I said before I might come away knowing more then when I arrived so keep it going gentlemen.

Grit is the number of 'particles' in one square inch surface. So in case of our Coticule and BBW stones this is the number of garnets in one square inch surface.

The sharpening particles in Coticule and BBW stones are garnets.
Arkansas stones contain Quartz particles in stead of garnets.
Carborundum stones are made of carborundum particles.
Diamond plates are made of diamond particles.
And so on ... .

Grit is only an indication of the number of particles, it doesn't say anything about the shape of the particles and the way the particles are hold together.
These last two subjects are also very important for the behavior of the whetstone.

Originally Posted by ArdennesCoticule

Grit is the number of 'particles' in one square inch surface. So in case of our Coticule and BBW stones this is the number of garnets in one square inch surface.
...

According to what standard though? Per the European FEPA system? As I cited in my above post, there are several different systems for determining "grit" and they deviate wildly when you get into the finer abrasives.

Also, how did you determine the size of, and number of, particles per square inch? Destructive testing of coticule and belgian blue samples?

I'm not being combative, just curious. I really like my coticule and belgian, and want to know more.

Originally Posted by joke1176

According to what standard though? Per the European FEPA system? As I cited in my above post, there are several different systems for determining "grit" and they deviate wildly when you get into the finer abrasives.

I have to admit that I have no idea! I'm just repeating what I learned of my father. My father learned this from his predecessor and so on.

Originally Posted by joke1176

Also, how did you determine the size of, and number of, particles per square inch? Destructive testing of coticule and belgian blue samples?

The size, shape and number of particles are different for each stone. It's a natural formed stone.
We had a lab testing our stones about 10-15 years ago.

Well technically (we are in the advanced honing section) I'd imagine that mesh or grit or whatever is some measure of central tendency per square inch (or whatever). An average, for example, or a median. Or perhaps a maximum number per square unit. It is highly unlikely, however excellent the manufacturing or natural process that generates the hones is, that there is uniformity across the entire stone in this regard. There is also variability with regards particulate size - again, I would imagine that a measure of central tendency such as a mean or median size is what is being quoted in this regard. Or, given things are run through sieves, perhaps a maximum size is quoted. In any event, both the size of the individual particles, and how many of them fit into a square unit of hone, is variable. How much variability there is will effect the working of the hone in my mind.

When it comes to converting grits to microns it appears it is not exactly as simple as "one chart fits all". Based on a little analysis I did a while back, the constants in the conversion formula vary depending on who (manufacturer, and their processes/medium/particle geometry etc...) you are talking about. The relationship is basically an inverse one (of course). For those interested the results are here.

James.

I am with Bart on this subject. I also feel that the particles per square inch, size of the particles, what the particles are made of [garnets, diamond, ceramic etc] and what shape the particles are, effect how they cut and how smooth the edge becomes. My observation of the DMT 8EE 8K seems to make my edge a lot rougher than a Norton 8K or Shapton 8K which makes me believe that there are less particles per square inch. This would allow the diamonds to cut deeper into the steel per stroke. I don't have any scientific evidence or proof. It is just an observation and feeling.

bj

There are standard ways to relate Grit, Mesh and Particle Size. Please see the table below, it's just that simple. Bart, please don't burn up your slide rule on this one, it has all been worked out! Enjoy gents.