04-26-2018, 03:36 PM
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.