"Toothy" coarse edge finish on Edge Pro/Haptone/Tsprof?

I recently checked my BESS tester and I can verify that Gilette Platinum double-edged blades score in the 40-50 BESS range. My personal best was with a Kubey Momentum in AUS10 that scored a 35.
 
I was just curious what that type of common razor blade would score, was happy to see I've gotten knives sharper. I'm still an amateur so my best score so far was my Laconico Keen in S35VN which came it at an even 100 BESS-C. It actually took me by surprise since I sharpened it quickly on my Work Sharp with the blade grinding attachment, followed by a quick strop on 1 micron on leather.

I'm waiting for the diamond matrix 80 and 4000 grit stones to arrive before I really go for it on my Edge Pro. Ever since I got my BESS tester my goal has been to get below 100, it's proven to be as difficult as I expected!
 
Honestly I think the BESS tester is the best piece of sharpening equipment I own ... and I own a lot. 😂

It's so valuable to have an objective test to tell you if what you're doing is making your knives sharper, duller, or making no meaningful difference. Keep practicing and testing and you'll get scores well below 100 in no time.
 
Looked into them a bit. Not sure if I understand it right. It's measuring the force to push cut through a small aluminum wire more or less. Seems like if you want to quantify sharpness it'd take into account both push and slice cutting. I like using nylon straps, but I cut a lot of them at work so it's not like I'm buying them just to cut them. Unless I'm missing something with bess testers it'd be fairly easy to make a more accurate system that took both push and slice cutting into account. If you took the variables out of how I "test" with nylon webbing. Make sure the nylon is made the same or you have a ton of the same batch. Tension the nylon the same. Apply the same force to nylon through blade. Ability to hold force and a guided stroke to eliminate human error. You could measure cut depth of pressure alone and pressure plus slice. Just by feel the nylon gives a ton of feedback. I'd be kinda surprised if I couldn't do my "test" and guess it's bess results fairly accurately once I knew how they compared. Also pretty sure that a knife that slice cuts like crazy would get a fairly bad bess score. A toothy edge is great at slicing through it with almost no force, but a mirror can push cut it with almost no force. I'm fine with doing it by feel but if I wanted to quantify it with a number I'd figure this out for sure.
 
stonemedusa6264 said:
Looked into them a bit. Not sure if I understand it right. It's measuring the force to push cut through a small aluminum wire more or less.
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It's not aluminum wire, it's actually just plain old thin (approximately 0.2mm) fishing line - possibly fluorocarbon type.
 
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stonemedusa6264 said:
Looked into them a bit. Not sure if I understand it right. It's measuring the force to push cut through a small aluminum wire more or less. Seems like if you want to quantify sharpness it'd take into account both push and slice cutting.
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These discussions always seem to devolve into semantic debates. The BESS result is just a proxy for the width of the edge apex. The smaller the apex, the lower the score will be. A BESS score of around 300 signifies an apex width of around 0.6 microns. A BESS score of around 50 equates to an apex width of about 0.1 microns. That's true of a polished edge which will excel at push cuts as well as a toothy edge that will excel at slice cuts. In either case, the edge with the narrower apex will cut better than the edge with a wider apex, so the BESS score is relevant no matter what kind of edge you prefer.

The main drawback of the BESS tester is that each test measures a tiny part of the edge, so you have to test several sections of the edge to ensure that the result is consistent.
 
I could see people getting heated over it. Luckily so far none of them have found this. I wasn't saying it was irrelevant. I was hoping if I planted the seed someone might do the work to make a testing system like that. I'd be curious to play with a bess but since I don't have one I test with random materials. The nylon gives me more feedback than anything else I've found. It's good simple fun to take a mirror polished edge to a nylon strap with tons of tension too. You barely make contact across the web and it pops n goes flying. One of my coworkers normally rocks a beater knife. He's used to sawing through it. I gave him my knife the one day we were on a roof. He ran around slicing nylon we didn't need to cut yet with this giant grin. It's hard to explain how much fun it is.
 
stonemedusa6264 said:
It's good simple fun to take a mirror polished edge to a nylon strap with tons of tension too. You barely make contact across the web and it pops n goes flying.
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It's interesting you mention the tensioning, because this is the exact reason how some guys make videos with insanely low BESS numbers (less than 5 in some cases) with their Edge-on-up testers. The test can be very flawed.

There really is no real proper standard and numbers can be wildly different depending on how the line is tensioned. Some use 100g weights, but then the tensioning screw itself creates variable additional tension on the line. Seeing the numbers vary so much, I eventually designed my own tester with tensioning screw that has no effect on the tension, working kind of like a vise more than a screw.

With the Edge-on up replaceable media, the more the line is tensioned, the easier it cuts. Even the clips they provide can also yield a flawed result, if the prongs are bent open a bit thereby adding more tension to the line.

I've experimented with many different pre-tension levels to the line and if you tension it enough, even a fairly blunt knife can show insanely low numbers. From what I've tried, zero line tension up to about 20 grams is what gives the most accurate numbers.

It would be fun to get hold of a standard nylon straps to try and build a scale that measures cutting force and speed, I just don't know where one would even start to pick a nylon straps that would be standard, consistent and widely available.

And you're right, cutting straps under tension with a sharp knife is very satisfying! 😁
 
Oh yea. I think the stuff I see a lot of is from europe n rated at 7700kg(8 tons) so it can be under some load. How tight it is makes a big difference. I could see that changing things with the bess. I could probably get loads of it every year but I don't know that it's the same. Even if it's in the sun all summer vs fresh out of a shipping container makes a big difference in how it cuts.
 
I use a 100g weight to set the line tension on my bess tester, not the end all be all but it helps with consistency.
 
777 Edge said:
It's interesting you mention the tensioning, because this is the exact reason how some guys make videos with insanely low BESS numbers (less than 5 in some cases) with their Edge-on-up testers. The test can be very flawed.

There really is no real proper standard and numbers can be wildly different depending on how the line is tensioned.
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Tension matters to a degree, but in my experience the biggest variable by far is speed. I can easily get <30 BESS scores if I pull the string tight and then bring the blade down fast, like a guillotine. OTOH, I can get *very* consistent results if I pull the string just tight enough to remove any slack and then take 3-4 seconds from the time weight begins to register until it breaks.

My cheat record is a BESS score of 5. ;)
 
Blade Lab said:
Tension matters to a degree, but in my experience the biggest variable by far is speed. I can easily get <30 BESS scores if I pull the string tight and then bring the blade down fast, like a guillotine. OTOH, I can get *very* consistent results if I pull the string just tight enough to remove any slack and then take 3-4 seconds from the time weight begins to register until it breaks.

My cheat record is a BESS score of 5. ;)
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I haven't tried cheating the tester, always going very slow, but am aware of the methods people use.

I bought the tester to have a way of quantifying my level of sharpness as I try to improve so I have zero motivation to cheat. It has been frustrating at times when I keep scoring in the 200-250 range after trying very hard freehand, especially when working with super steels finishing on coarser diamond plates. Looking at those edges with my pocket microscope they look great, a little ragged from the coarse finish, but great none the less. My freehand skills just aren't good enough yet to score really low on the bess tester coming off a coarse stone/plate followed by stropping.

I've found I have a higher chance of getting a score below 200 if/when I finish a blade on higher grits. I always finish with light stropping no matter what I stone/plate I finish on to help remove any final microscopic burr.

It's the high vanadium steels that I struggle getting great bess scores with, but those are the same steels I prefer to keep very toothy. All of my Japanese kitchen knives I've sharpened freehand score in the 130-150 range, so I know my freehand skills aren't "terrible". Those knives are all simple high carbon steels (White #1, Aogami Super, Blue #2) that I sharpen with either Shapton Pro or Gesshin stones, finishing on either the SP 5K or Gesshin 6K, followed by the same stropping technique.
 
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