Thread: Sharpen This!

I was taught freehand sharpening for wood carving tools. Some unwritten tricks which really helped.
At some point, I bought a copy of Leonard Lee's 'Practical Guide to Sharpening.' I read it.
Along about page 35 or so are 2 pages of electron microscope photographs of steel edges, sharpened with various techniques.
Clearly debunked some points of mythology that I'd been taught as dogma. Dogma you can step in, as I discovered.

Using "try-sticks" to test the progress of my activity, I began to omit steps. Particularly true for Pacific Northwest style carving edges.
Testing edges in woods is the cleanest method to learn what really works and what doesn't.
I've been reading loud and hot arguments about how to measure bevel angles, how to describe bevel angles.
How half-angles are oh so important as labels. . . . . .. . So obtuse as to be funny.

Where do you start?

I've made a quick read through the ten parts and my conclusions are: 1-4 are a bunch of truisms and platitudes. The fifth and eighth entries are seemingly contradictory, if we accept the Procrustean and technically baseless reasoning presented in part 5. Parts 6 and 9 are also at odds in a way, if there's no difference between grind profile as discussed in 6 why is a honing jig as discussed in 9 even necessary? Part 10 is irrelevant, gives no information.

I'd like to hear from somebody who does or studies sharpening professionally. Somebody who sharpens knives in a lumber mill for example. Or an engineer who works with scalpel blades or diamond microtome knives. In otherwords somebody who knows what sharp really means and knows how to measure it.

A sharpness tester.....Sharpness tester I recall reading about it in another forum not long ago.

Biologists work with scalpel blades. Many biologists spend their days and years with either glass or diamond knives, cutting 5 or 6 nm sections on an ultramicrotome
for transmission electron microscopy. I did for some years, to earn a PhD at LaTrobe.

There's no connection between the molecular construction of carbon in a diamond and the muck that we call steel.
Read Leonard Lee first.

Here, we use a lot of ceramic blades in our forest industry. It's naive to suppose that they last forever. They last longer but are far more difficult to maintain.
Accept steels for all their shortcomings. Enjoy carving.

Originally Posted by Robson Valley

Biologists work with scalpel blades.

Indeed. I'm talking about an expert who makes or designs the blade, not merely a user. Scalpels and microtome blades are poor tools for working wood but they are very sharp, much sharper than any chisel or plane blade.

Originally Posted by Robson Valley

There's no connection between the molecular construction of carbon in a diamond and the muck that we call steel.
Read Leonard Lee first.

I think it important to point out that steel isn't made up of molecules. Bashing a bit of steel with a hammer does not rearrange it's molecules because steel isn't made up of molecules in the first place. The bonds that hold a bulk metal together are very different from those that occur in molecules known as metallic bonds. The bonds formed in bulk metals are responsible for, among other things, their electrical conductivity and other useful physical properties. Diamond is a network covalent crystal, not an assembly of molecules. Linus Pauling described the various types of bonding in his seminal work The Nature of the Chemical Bond. Linus Pauling and The Nature of the Chemical Bond: A Documentary History - Special Collections & Archives Research Center - Oregon State University

Originally Posted by Robson Valley

Here, we use a lot of ceramic blades in our forest industry.

The person/people that make those ceramic blades know what 'sharp' is in the sense I use the word above. The average woodworker, even the popularly esteemed woodworker, has personal experience and opinions on sharpness but what does the engineer or scientist who specializes in sharp things think?

That's why I suggest reading Leonard Lee first. The grand old man of Lee Valley & Veritas, if I'm not mistaken.
The structures of steels and carbon are different. Too many ignore the fact.

L.L. did the exploratory work with research scientist engineers with the National Science and Engineering Research Council of Canada.
It's a good modern read which builds on the published body of prior research.

I'm not trying to challenge anyone or whatnot, but I think it's important to point out that this conversation has kind of gone in the direction that the blog posts are trying to avoid, which is to overcomplicate and over-science sharpening. I think the whole point was to attempt to make it concise and somewhat approachable, not so much to unlock the code of sharpening.

The only thing that he says that I'm not sure I completely agree with is that polishing a blade does not make it any more sharp, but it just extends the life. I think that the grooves at the cutting edge left by a coarse stone are enough to reduce its cutting power, which, in my mind, equates to sharpness, even though C.S. says that sharp is simply a zero degree radius.

If you want to reduce the discussion to the absolute minimum of anything like science, communicable understanding or informative discussion then yes, the message of Schwartz is correct. Do what works for you under the conditions you face, nothing else really need be said. Sharp enough is good enough.

Coarse grit shreds the edge. Finer grits make finer shreddings.
Very thin steels appear to be much more plastic in appearance than I ever expected.
So in service, a finely crumpled edge will act sharper for longer than a coarsely crumpled edge.

The SEM pictures convinced me to take a minimalist approach, testing in try-sticks of the woods I used.
I hone with CrOx/AlOx after 1500 grit. Used to go to 4,000 and finer. As I can see clearly, not useful.

Originally Posted by Luke Maddux

Interested in the thoughts of others.

I didn't really enjoy that. His writing style is quite abrasive, and I get my back up quite quickly when people talk down to me, which is how his whole "big rocks, little rocks" stuff comes across. His analogies seem a little strained.

I do agree with his assertion that sticking to one system that works for you makes sense. But let's be honest, if everyone did that, we'd never make progress would we? Someone has to try new things, and see if we can do it quicker or better.