The BESS "C" Sharpness scale, used with the Edge on Up sharpness tester

FREE Learning- Quantifying Sharpness

Professional Knife Sharpening Should Be a Measurable Process! You Can't Improve What You Don't Measure!

You should expect professional results from the professional knife sharpening service near you! Since I began making and sharpening custom knives, one of the things I'm most satisfied with is the final edge I put on blades. My system and tools give precise, repeatable results and very sharp edges.BUT, these edges have to this point been tested using anecdotal measurements. For example, "does it shave hair? How easily?" or "Will it slice phonebook paper? How smoothly?"

This type of opinionated quality control doesn't sit well with me, being a machinist who is accustomed to measuring features with instruments that have .0001" resolution. "How hard is this edge pulling the hair it shaves?" is not a quantifiable result, not a number I can share with other folks and have them KNOW how sharp my (your) edges are. Enter the new Edge On Up PT50A sharpness tester!


From the website: "The standard used to determine the sharpness of knives is called the BESS: Brubacher Edge Sharpness Scale. This scale was developed by Mike Brubacher, owner of Edge-On-Up. He has a background in sensor and test development in various industries. In 2012 he started developing a standard that could measure the sharpness of knives and needles. The result is the BESS standard that was quickly adopted by experts and enthusiasts as one of the most user-friendly methods to determine the sharpness of a knife."

A cleanly sharpened edge, accurately finished at Keith Nix Knives

This little instrument uses a certified and calibrated synthetic wire very similar to heavy fishing line, and a scale with 1 gram of resolution. The knife is pushed gently into the test media until the edge severs the "wire". The instrument reads the force required to cut the wire in grams, and that is the BESS score. What's more, the BESS score relates directly to the edge radius (yes, radius. No edge can be sharpened to a perfect apex). So if your sharpened edge rates 85 BESS, it tells you the edge radius of that blade is 85nm (a human hair is 60,000-100,000 nm, or .002-.004")

The BESS scale in the picture above gives comparative results. For example, there is a block between 250-350 on that scale, notated as "new high end cutlery edges". Another block between 150-200 says "utility razor blade". Another roughly between 25-75 is noted as "double edge razor blades". The knife I carry every day for a "box opener" needs a touch up, it just checked 208. To check out a quick little video from "Sharpening Supplies" of how simple this instrument is to operate, just click HERE!


This is going to help me refine and measure my process to the point where I'll be comfortable saying I'm delivering you custom kitchen knives that are as sharp as anyone in the country. Now I know I'll never get to the 50 gram level of a razor blade, and you shouldn't want me to. There are a couple of reasons. One, knives are much thicker than razor blades, with far more obtuse primary and secondary bevels, and that negatively affects the force required to cut the media. Two, an edge as keen and sharp as a razor would not hold up well in the kitchen, the sheath, on the cussing board, or the pocket. I'm thinking the right place to be for kitchen knives will be around the 125-175 mark (VERY sharp utility razor range), and probably about 150-200 for hard use outdoor knives. (Incidentally, that knife in my pocket at 208, still shaves but it pulls too much!)


I'm pleased to address sharpening again in the quest to improve quality overall. I settled on my sharpening system, stones, and strops early on in the shop setup. Since then I haven't really looked at it, because I was slicing phone book paper and comfortably shaving arm hair! If this gets us a few more points on the sharpness scale, I think we'll all be winners! To learn more about "How I Sharpen Your Knife", CLICK HERE!

More FREE Learning:

Quantifying Sharpness Part II

Quantifying Sharpness Part III

Knife Safety Tips


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Keith Nix Knives