Thread: experiments

Originally Posted by kevint

Thank you for your reply Bart.

What I was referring to by animosity was the sudden turn to accusation of bias, fraud, ignorance. This in spite of the fact the description of the method specifically mentions the aspects of lighting and limitations of the equipment. Ignorant statements about how the appearance of scratches can be manipulated to appear smooth or deeply furrowed, combined with assurance that these cannot be 30k because they are too coarse in appearance is far less than I expect from an intelligent conversation.

This kind of response, and I have seen it before. Along with the mindless buddy system of thanking up the rep, like some middle school popularity contest truly makes me question my participation here.

His photos do not demonstrate what he claims they demonstrate. To see submicron features requires a microscope capable of a very high magnification. There have been multiple papers published (Verhoeven's Knife Sharpening Experiments 2002 paper, and the Popular Mechanics article from the 20's) that show these scratches accurately, and both of these used 3000x magnification. Verhoeven used an electron microscope, and the PM article used a custom-built optical microscope.

The 25x magnification the linked poster used is simply inadequate by roughly two orders of magnitude. It is not ignorance nor mindlessness to point this out, nor is it ignorance nor a matter of popularity to note that this means that the linked poster is either unaware that he needs a much bigger scope or he is intentionally trying to deceive the readers. And it seems reasonable to point out that one factor that makes the ignorance option more likely (or at least more understandable) is the possibility that confirmation bias may have played a part. And it is not unintelligent to note that the sorts of effects that the photos do show are the sort that have tripped up previous attempts to analyse hone scratches with low-power microscopes. Nor is it out of line to describe how small differences in lighting can have a huge effect on the sorts of surface features that show up in the photos.

It is possible that the OP of the linked thread is absolutely correct in his conclusion that the Nakayama hone is markedly superior to the Shapton 30k. I've got both and think they're roughly equivalent, but it's possible that I'm wrong. But this conclusion is not bolstered by the photos in that linked article. I'm sorry to disappoint you, but the resolution is just too low. Even at 3000x the scratches are surprisingly small, and at 3000x you can look at the blade edge-on and measure the width of the cutting edge to the hundredth of a micron, and at that magnification the scratches are roughly the same size as the ones shown in the 30k shapton photo. So if the guy in the linked thread is right about those scratches, then somebody needs to tell Prof John Verhoeven at the University of Iowa that he needs to learn how to use an electron microscope. Or maybe, just maybe, it's the random internet poster with the 25x microscope that's wrong.

Maybe.