Thread: Natural Japanese waterstones

Wilbur, what does the X-axis represent? Time sharpening?

Pam

Originally Posted by NeilS

"Using natural stones will enable you to plane thinner (more sheen on the surface of the wood) and at the same time it will make the edge last longer.

... What I've been saying all along.

Nice to have something approximating proof that I'm not nuts!

Thanks, guys.

Oops - forgot to label the axes.

X axis = grit number. Y axis = number of particles of that size. Moving to the right on the X axis represents smaller particles.

Thanks, Wilbur. I think there may be a problem in talking about the number of particles since the sharpening process doesn't necessarily increase the number, which is determined by the number of particles temporarily embedded/conjoined as the stone. Do you say this because the process splits each grain?

Pam

To my thinking, it's not the absolute number of particles that's important in this model/theory, but the relative distribution of the sizes. The main point I was trying to illustrate is that I think that a man-made waterstone has very uniform particles, while a natural waterstone has less uniform particles, even though the average particle size may be the same between the two. The second point is that as you use the natural waterstone, the particle sizes break down so that they become smaller and somewhat more uniform, which doesn't happen with the man-made stones.

For my illustration, I generated these curves using the function for a normal probability distribution, but I couldn't figure out how to manipulate the curves so that they all peaked at the same height.

In fact, if I understand the math right, each curve represents the same number of particles in total, just distributed in different ways. That's the reason why the skinnier curves peak higher. The area under the curve for all three curves should be the same.

Not clear here, by any means, but I'm thinking -- as the particles break down, don't they increase in number? They can't just get smaller: they must fragment. No? After all, matter can neither be created nor destroyed: it can only change in form... as me late, great mum used to tell me whenever I said, "But I can't find it!"

Becky

The particles would increase in number as they break down, of course. Again, what I was trying to illustrate was not the absolute number of particles, but how the particle sizes varied for each situation.

Hi, Wilburpan --
I should've been more specific. I was responding more to the question Pam raised.

Becky

Originally Posted by wilburpan
"Now, I have no evidence that this is what happens, but this model certainly provides a plausible explanation for many of the observations about how man-made and natural Japanese waterstones behave."

I tried to to get a pic of the particles pre and post usage. I had them lined up just perfect, but sneezed, and they all got mixed up and I lost a couple (at least). Oh well.

On a less serious note I found this on the JWWF (real pics!)
okanna.blogspot.com

I would surmise that there is also a difference between natural stone and man-made in shape at this scale and no doubt the shape affects the cutting action.
I think natural grit is kind of like free range - once its "free", it really feels no compunction to remain as it started out.
(no, I'm not telling you where I live, lest someone sends the guys in the white coats)

Steve

Originally Posted by wilburpan

To my thinking, it's not the absolute number of particles that's important in this model/theory, but the relative distribution of the sizes. The main point I was trying to illustrate is that I think that a man-made waterstone has very uniform particles, while a natural waterstone has less uniform particles, even though the average particle size may be the same between the two. The second point is that as you use the natural waterstone, the particle sizes break down so that they become smaller and somewhat more uniform, which doesn't happen with the man-made stones.

For my illustration, I generated these curves using the function for a normal probability distribution, but I couldn't figure out how to manipulate the curves so that they all peaked at the same height.

In fact, if I understand the math right, each curve represents the same number of particles in total, just distributed in different ways. That's the reason why the skinnier curves peak higher. The area under the curve for all three curves should be the same.

OK. Wilbur, I think the process is a little different: particle breakdown should happen at one point and maintain rather than decreasing. Or, it's not a bell curve process. This is very difficult stuff to model.

Becky, I'm not at all sure we know what's happening here. You think the stone particles break down, get smaller? Right? That's reasonable. But maybe the particles appear smaller because they're separated from the main body. So does the steel increase the number of particles or merely separate them from the "stone?"

Pam

My understanding is that the particles "compress" as you use the stone -- which, to me, implies they're being broken down rather than simply released from the stone. Also, just knowing the basic properties of stone, it all breaks down, no? I can't imagine any stone that wouldn't yield its integrity under the repeated stress of metal pressed and compressed against it.

On the other hand -- since I love to argue with myself -- if the stones are what started out as, say river silt, maybe they're already in the smallest possible particles -- except (arguing again with myself) the fact that it's a solid, durable stone makes me wonder if this is possible.

Although (), since sedimentary rock undergoes compaction (right term?) -- again, we're dealing with compression. If the stones are, in fact, siltstone... which is what I always assumed... then the question is can silt be broken down further than the state in which it formerly existed?

It still seems to me, arguing on an atomic (molecular?!) level, there's nothing in rock particles that couldn't be broken down further through the sharpening process.

Does this mean we're dabbling in atom-splitting? Or is it just hair-splitting? Or maybe it's just my personality splitting: .

Becky (and whoever else is in here with me)

Originally posted by Yojimbo -

"My understanding is that the particles "compress" as you use the stone -- which, to me, implies they're being broken down rather than simply released from the stone. Also, just knowing the basic properties of stone, it all breaks down, no? I can't imagine any stone that wouldn't yield its integrity under the repeated stress of metal pressed and compressed against it.

On the other hand -- since I love to argue with myself.....etc.,"

I think you're both right.

Actually, it makes sense that the particles of stone will abrade themselves as well as the steel. And the steel particles will also abrade the stone and the bevel while they are freshly removed (they will quickly dull and perhaps provide more of a burnish, but certainly less "cutting" action). But even dulled, they must get pushed against the stone particles and help free/crush them (and break up into smaller bits). One of the desired attributes of kamaji is that it contains impurities which help wear the stone and expose fresh (sharp) grit. But this would also ensure grit is released constantly as well, adding to the slurry. Maybe its the depth of the slurry which slows down the rate of cutting (some of the loose grit will just move along and not dig in, in effect making the cutting action less effective but still present and the result is a finer scratch pattern.

On other tangents (worthy of entry to the loony bin no doubt*), can there be some chemical reaction because of the water? (other than straight oxidation - but even that on a near molecular scale must have an effect?)

(*no doubt at all)
And then there's the different types of steel. Maybe with pressure and the abrasion action, the austenite, pearlite, cementite, martensite, and ferrite, get transformed into say, Austenmartin or ferrocement (with the correct pearlcentite of each), etc.?

teve

teve:

What a guy!

ecky

Careful - don't encourage me. I'm sure there are a lot of others too pearlite to tell me stop.

Steve