Sharpening methods

[Chris Knight]

Pick one method, get good at it and forget the rest.

 

[Beau]

Pick one method, get good at it and forget the rest.

Spot on Chris.

 

[Saer Llongau]

I can't really make the case that one shouldn't buy japanese natural stones (everyone should do what pleases them in my opinion -even if it makes other people on forums upset because it doesn't meet said other peoples' standards), just that there's no great need to.

I once read an article by Shinichi Watanabe in which he explained that a Japanese natural stone can have a hardening effect on the edge. Supposedly it has something to do with a reaction between some elements in the stone and the steel. I don't know if it's true and I can't really say I've noticed it myself but if it does happen there's certainly a case to be made for Japanese natural stones.

 

[D_W]

I think one would have to do a practical test between natural and synthetic edges to see if it makes much difference. If such a thing occurs, it also does with oilstones (and I've hard the same attribution given to them in terms of edge burnishing/work hardening).

Regardless of whether or not it occurs, I've come to appreciate the much more even feeling natural edges. They don't have the strange quick initial loss of edge that the fine synthetics do.

And the aesthetics (albeit not a necessity, but a nicety) are really satisfying, especially on something with folded wrought iron (or just wrought with enough silica to see the layers).

 

[Cheshirechappie]

I can't really make the case that one shouldn't buy japanese natural stones (everyone should do what pleases them in my opinion -even if it makes other people on forums upset because it doesn't meet said other peoples' standards), just that there's no great need to.

I once read an article by Shinichi Watanabe in which he explained that a Japanese natural stone can have a hardening effect on the edge. Supposedly it has something to do with a reaction between some elements in the stone and the steel. I don't know if it's true and I can't really say I've noticed it myself but if it does happen there's certainly a case to be made for Japanese natural stones.

That only works if you sharpen under one of Derek's pyramids, on an accurate north-south alignment, during a full moon, and wearing ceremonial clogs, braces and a flat cap.

 

[D_W]

I can't really make the case that one shouldn't buy japanese natural stones (everyone should do what pleases them in my opinion -even if it makes other people on forums upset because it doesn't meet said other peoples' standards), just that there's no great need to.

I once read an article by Shinichi Watanabe in which he explained that a Japanese natural stone can have a hardening effect on the edge. Supposedly it has something to do with a reaction between some elements in the stone and the steel. I don't know if it's true and I can't really say I've noticed it myself but if it does happen there's certainly a case to be made for Japanese natural stones.

That only works if you sharpen under one of Derek's pyramids, on an accurate north-south alignment, during a full moon, and wearing ceremonial clogs, braces and a flat cap.

It probably actually occurs to some extent with all stones when the primary abrasive and the steel are close together.

Work hardening of an edge is an established thing with barber linens. Same principle, except the linen is further below the hardness of the edge and the burnishing happens more slowly.

Whether or not that hardened edge is blasted off on a tool in the first few strokes is an entirely different thing.

Once in a while, i go back to synthetics for a little bit to see if I'm just being nutty for preferring the natural stones now, and there is that microtoothy blinding uniform sharpness that the really fine ones have (even the old fine ones), but I seem to see more small edge defects in edges that count, and the uniformity of the edge doesn't last as long. Does the uniformity matter? Only if you're finish planing or paring a show surface, I guess. But I like it.

 

[Saer Llongau]

I've come to appreciate the much more even feeling natural edges. They don't have the strange quick initial loss of edge that the fine synthetics do.

The quick initial edge loss that you get with a synthetic is actually because the edge is very even. A natural stone produces a uneven edge with high and low serrations. This causes the edge to wear in an uneven way and that's why the edge off a natural lasts longer.

 

[bridger]

I think one would have to do a practical test between natural and synthetic edges to see if it makes much difference. If such a thing occurs, it also does with oilstones (and I've hard the same attribution given to them in terms of edge burnishing/work hardening).

Regardless of whether or not it occurs, I've come to appreciate the much more even feeling natural edges. They don't have the strange quick initial loss of edge that the fine synthetics do.

And the aesthetics (albeit not a necessity, but a nicety) are really satisfying, especially on something with folded wrought iron (or just wrought with enough silica to see the layers).

If there is a hardening effect due to burnishing it would be most pronounced with something like a jasper that barely cuts at all. I don't know how hard the jnats in question are but in any case it'll be a transitory effect but should be measurable, somehow.

If the hardening effect of jnats is supposed to be from a chemical reaction between the stone and the steel I think I just call bullshit now and wait for some hard data.

 

[D_W]

I have no idea what would cause a chemical reaction that would lead to hardening. If there was something that did that materially, we'd all be using it.

there were stones called "chemical stones" years ago that purported to hone using chemicals or something, but they were never that popular. JWW sold them here, and like most of their stuff, they were probably twice or more the going rate vs. anywhere else. Even when I first got into woodworking, it sounded either bogus, or like intentionally putting corrosive material onto your stones. I didn't like either of those.

Here is a university (or at least professor-based) analysis of the stuff in japanese stones. The aluminum is aluminum oxide. Almost without exception, someone sees that and states that it's not possible for it to be the same thing as we call aluminum oxide, but I don't think that's the case. The stones have volcanic ash in them, and there's plenty of aluminum oxide in volcanic ash.

https://0ea5c8fc-a-62cb3a1a-s-sites...a-6NQQ0TYyZT7E92rQA_P3X5scGPg=&attredirects=0

I know little about chemistry, so I have no idea what on that schedule would harden steel chemically.

 

[D_W]

re: the al-ox thing. Very interesting that the aluminum oxide concentration in Mt. St. Helens ash was 18%, vs. the 16.67% average in the link above (or whatever it was). That's close!!

http://onlinelibrary.wiley.com/doi/10.1 ... 9/abstract

In fact, the whole profile looks like the composition of a japanese natural stone. Presumably the stones are just compacted vocanic ash (I knew some part of them was, but it looks like the entire stone itself is just compacted ash).