Thread: experiments

Not really sure what we're looking at there. Is it all bevel? with a hard/soft steel boundary or bevel and blade.

In any event, in the part that is blade or soft steel there are large discolorations/bumps/pits or whatever they are. There are two especially large ones close together almost dead center in the pictures. If you use one or more of those marks for reference it seems that the scratches above and below the marks are erased in the progression of pics but but the mark remains virtually uneffected. Would those be tiny pits in the metal?

buddy system ?.... like some middle school popularity contest ?

It’s all over the forum… but I honestly thought I was the only one to notice.

My comments have been strictly about content, gentlemen. There is nothing against the man in what i have said. I have respect for everyone that has posted here. ive read your posts I was full of slurry there for a few minutes, I feel well lapped now

Contradictions are not hard to come by when honing. If you don't see it, my pointing any out will add no clarity to the subject.

First let's remember that is not a razor bevel. I believe you can tell nothing about the edge condition in these pictures. they are for scratch comparison.




what you are seeing if it is not clear is described in the article. It is a forge weld of hard high carbon steel edge to thicker backing of wrought iron.... We know that a 30k ceramic stone will polish to a high mirror and it will leave very small scratches. You can guess this even if all you have is an 8k
you can see the difference of the kasumi finish of the natural stone very clearly with the naked eye. the naked eye appearance of each type is perfectly aligned with the side lit magnified photos.


The reason one is shiny and the other matte, is the difference in the scratch pattern. They are radically different. There are two things that may explain the dichotomy. Both related to binder as Bart mentioned. The nat binder is weak allowing clumps of particles to be released and easily break down. The synthetic may be releasing clumps of particles; however, the binder "might be" keeping those small particles acting as single larger particles.

Originally Posted by Quick

Not really sure what we're looking at there. Is it all bevel? with a hard/soft steel boundary or bevel and blade.

In any event, in the part that is blade or soft steel there are large discolorations/bumps/pits or whatever they are. There are two especially large ones close together almost dead center in the pictures. If you use one or more of those marks for reference it seems that the scratches above and below the marks are erased in the progression of pics but but the mark remains virtually uneffected. Would those be tiny pits in the metal?

some could be pits, but I don't feel like looking again Quick. I believe you are seeing inclusions, often silica which is considered a desirable condition in the iron.

Originally Posted by mparker762

Finally found the Verhoeven paper, which should help correct the overemotional rhetoric and ad-hominem attacks in this thread.


Experiments on Knife Sharpening
September 2004
Prof. John Verhoeven
Emeritus Professor
Department of Materials Science and Engineering
Iowa State University

Experiments on Knife Sharpening


On page 19, figure 23, he shows a blade sharpened on a 6000 grit waterstone, at 3000x and 800x resolutions. Notice how small the grooves are, even at 800x magnification.

On page 30, figure 37, he shows a blade with a secondary bevel formed on chrome oxide. He doesn't give the grit, but he does describe it as the standard chrome oxide block sold in woodworking stores for honing chisels. At best this is the 0.5 micron Lee Valley block, at worst it's the coarse stuff that's blended with other abrasives. If it's the 0.5 micron chrome oxide then the grit is comparable to the grit of a 30k Shapton (my Shapton is 0.48 micron). Even at 3000x, the grooves in the secondary bevel are very thin and very shallow, and are therefore unlikely to be visible at 25x as the author of that linked article claims. Admittedly I'm comparing a 0.5 micron paste to a 0.5 micron stone, but Verhoeven shows an awful lot of photos of 1k, 6k, and 8k honing marks at a variety of resolutions, and the marks from even these relatively coarse hones are surprisingly small.

I do not apologize for being negative about the linked post, nor for being contradictory about his assertions. But if Prof. Verhoeven's pictures are accurate depictions of micron and submicron-scale honing marks, then it is clear that the centimeter-scale photos in the linked thread must be showing much larger honing marks and not the 0.5 micron - 0.2 micron striations that the Shapton and Nakayama hones would be producing.

I hope I haven't soured you on the Verhoeven paper, but it is well worth reading front to back. He shows comparative micrographs of commercial Gillette razor blades and a straight razor that was honed by somebody that used it, and the straight razor comes off looking quite well. And the photos are quite eye-popping.

I have read the paper and discussed it here several times.