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I think micro serration is important for the knife edge. But the way to confirm this is not simple.
There is a way to cut tomatoes, but purchasing tomatoes for this is inefficient. And Steve Bottorff has introduced kitchen towel cutting, but I think this is inefficient too.
Is there another good way to check for micro serration?
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The two things I always use to test any sort of edges are adding machine or receipt paper (without bias) and manila rope.
They are both abundant and almost free.
I've also used a lot of waistbands from old clothes for coarse edges and Charmin extra strong TP for refined edges.
Examining the cuts in paper under magnification will yield more detailed information of the edge, especially of tooth (micro serration) and burr.
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I'm curious... Why do you guys prefer non-bias paper? I have a bunch of this one catalog with thin paper that is very fibrous in one direction. Cutting the top edge of the paper is very different than cutting from the long side. Cutting the side of the page always cuts easily, but at a slight angle from the top of the page is difficult.
With that paper, when ripping across the fiber from the top edge of the page a polished edge, unless extremely sharp, tends to ride when slicing, but a toothy edge slices through nicely.
Oh, yeah, +1 for using magnification, only I like to look at the blade edge rather than the cut in the paper. It’s nice to be able to actually see it. This is without a doubt a super extreme example, but polished vs toothy:
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This is a stretch, but paper with bias might be somewhat like cutting manila rope. You can go across the grain or with the grain. It could be the difference between cutting and separating fibers. I'm not sure. I think it can only be helpful to take that variable out of the equation though.
Also, there are different ways to cut paper. Push cutting is different than slicing. Angled cuts are different than straight cuts with bias paper. Roll up a piece of paper and slice it straight across and at an angle.
Cutting miles and miles of paper eventually involves your senses of hearing and feel more than your sense of sight. A coarse edge sounds and feels much different than a refined edge. An edge with a burr also doesn't cut straight, and one side of the cut looks cleaner than the other.
I don't have a magnifier like yours, Mr. Grepper. I bought a USB microscope, but I got frustrated quickly. My 60x magnifiers cost $5, and I can examine the whole length of an edge in seconds. It's most meaningful when you learn to recognize what you're seeing.
It's easy to observe the burr with each pass across a stone. That's what lead me to the conclusion that it's most efficient to remove the burr by working the burr side alone. That's something I simply learned by accident, due to being able to make the observation with the 60x mini-microscope.
As soon as you can see the last traces of a burr evaporate into a clean scratch pattern to the EOTE, the edge is remarkably clean. No wasted effort going back and forth creating more burr or chasing part of the burr.
With absolute due respect as always, Mr. Grepper, these are just my humble opinions, but also, I don't think it's possible to compare edge trailing on a belt to edge leading on a stone. The result can not be similar.
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This is hardly scientific nor quantifiable but my brain/thumb can ID a sharp, toothy edge very quickly. I was amazed at the difference in feel with the first toothy edges I produced. It's like your brain immediately sounds an alarm the says "Danger! Extremely sharp edge under your thumb!". A 100 polished edge does not produce this reaction but a 225 toothy one does every time. Could just be me and my brain/thumb but the sensation is unmistakable for me. Other than that, I rely on microscopic examination such as provided by our Ansel Adams of knife edges, Mr. Grepper.
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No doubt everyone feels edges with their thumb/fingers. People who do it on a daily basis generally learn the "3 finger" because it gives you the maximum feedback.
I don't think everyone needs to do it. It's not easy to master, but I can teach nearly anyone how to do it in person. I can not explain it in writing.
My question, Mike- Can you approximate BESS sharpness with your fingers? I don't know anyone who can. A toothy edge will always be "grabbier" than a refined edge, while the refined edge can actually measure very much sharper.
The 3 finger is easily much more definitive, because you are actually using your fingerprints, not the pad of a digit.
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The answer to your question Mark - No. Not even close and you've already identified the reason why. Quite frankly a brand new DE razor blade doesn't leave my thumb with the sensation that it is particularly sharp. It is though and one short linear motion down the edge would prove it. A 200 toothy edge immediately sends chills. Unfortunately a 300 toothy edge does as well. I'm equally unqualified when it comes to cutting paper. I struggle sometimes to get a DE blade started but can just slice away with a 200 toothy chef's knife.
While we're on that subject, I ran across an old Popular Science article some time ago (sorry, could have been Popular Mechanics) (maybe 1970's) about an engineer who was consulting to the meat processing industry. He was trying to devise a means of testing edge sharpness. He rejected common papers as a test media due to what he described as "tear propagation". In this case, tear propagation was described as being sort of a self-sustaining force that, once initiated, worked somewhat independently of the edge to separate the paper. He ended up using paper embedded with a cross-hatch webbing to counteract the tear propagation.
