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  1. #1
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    Default Experiments with the BESS system

    A couple of weeks ago a new member, Knifegrinders, posted concerning a promotion of the BESS sharpness testing system (No man is prophet in his own country?). The conversation developed for three pages with myself and some other forum members trying (in vain ultimately) to get some data from the OP as to how well the BESS system works for measuring sharpness.

    In a nutshell, the various BESS devices measure the force required to cut through a piece of monofilament line. This figure, abstracted from their patent application (https://patents.google.com/patent/US20160069785A1/en) shows one implementation of the device.



    The blade, held in a clamp is positioned underneath a movable plunger 30 which carries the test filament holder 34. Weight in the form of lead shotgun shot is placed in a cup that rests on the platform surmounting the plunger. The mass of shot presses the test filament against the edge of the knife. After the filament is cut the mass of shot is determined by weighing on a scale.

    Despite the lack of any data supporting the utility of this technique I decided to buy the filament holder ATF10 via Amazaon https://www.amazon.com/dp/B06WGPR29Y for $35. Unfortunately none of the test media were available for purchase at the time or now, two weeks later.

    BESS sharpness tester medium unavailable.JPG


    The ATF10 arrived late last week, here it is.

    ATF10 a.jpgATF10 b.jpg


    The test filament is inserted into the hole shown on the top of the device and is held in place by the thumbscrew (left picture), laid down the groove cut to the other side and secured by making three quarter turn around the shaft of the opposite thumb screw.

    Looking at the patent application I noticed:

    So I searched 'teflon monofilament' on eBay and came up with these:




    Kastking Masters brand Teflon impregnated monofilament lines in 4, 6 and 8 pound test that correspond to 0.007", 0.008" and 0.010" diameters as described in paragraph 0012 of the patent application.

    Next for my test blades. I tend to use all of my tools, no matter how expensive or valuable they are, so finding unused sharp edges took some looking. I ended up with these:




    From the left is a new Feather brand #11 scalpel blade, a new GEM brand Teflon coated industrial single edge razor blade, a new Dewalt utility knife blade, an un-used Bridge City Toolworks Hp6v2 rabbet blade and a used 1" Blue Spruce Toolworks paring chisel for a twist.

    For determination of the force required to cut the test articles I used a Mettler PM4600 top loading laboratory balance. It was set to read to 0.01 gm with a maximum capacity of 4.6 kg.

    Mettler PM4600.JPG
    Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.

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  3. #2
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    So - what's the plan??

  4. #3
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    The first round of tests were conducted in 10 replicate cuttings using each blade on each test article or 5 blades X 10 cuts X 3 filaments for 150 individual measurements.

    For a second twist I evaluated the used Blue Spruce chisel on each of the different weight filaments and then I made more measurements as I sharpened it through 6 grades of sharpening stones.
    Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.

  5. #4
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    So I'm going to preface this comment with the fact that I've got no experience in sharpening what so ever...

    I'm all for data and experimenting where the potential outcome of the research will provide a benefit that outweighs the time and money invested... but to me, this falls in the category of my signature... its a complex solution to a problem no one really has... the return on investment doesn't seem to stack up for mine... you sharpen your blades till their sharp enough for your requirements... will shaving a micron (or whatever the measurement is) off the blade really make a noticeable difference at the end of the day? I think that's what caused such a heated discussion on the other thread... sharp enough is sharp enough, it doesn't have to be a magic measurable number...

    I'd argue that chasing the "perfect" sharpness on a blade using this system will likely only cause frustration, waste time, and further wearing on the blade from sharpening and resharpening till you get the blade "perfect"...

    But again, i haven't sharpened anything yet so i could be way off the money here... I'm not trying to dissuade you from your research, just my opinion...
    ​Coming Up With Complex Solutions to Non-Existent Problems Since 1985

  6. #5
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    Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.

  7. #6
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    Here are the media used for the sharpening. The blade was held in a Somax honing guide. The guide was left in place to ensure, to the degree possible, that the included angle of the blade remained the same throughout.



    For sharpening:
    Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.

  8. #7
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    I agree that chasing the perfect anything can be quite frustrating but I don't think anyone (except maybe the people selling the Bess system) suggests everyone buys the Bess system. The whole idea about "data and experimenting where the potential outcome of the research will provide a benefit that outweighs the time and money invested", is for just a few people to test for example, knife sharpening protocols, to determine if "this" is better" that "that". They then tell the rest of us so everyone doesn't have to do testing and that really saves us time. Especially when it tells us not to waste our time on something . We are fortunate that the world has a limited number of people like Rob that are prepared to and like doing this. If we had none we'd still be back in caves.

    My understanding about the Bess system testing by the manufacturer is that they were able to correlate the force needed to cut the monofilament correlated with the micron size "thin-ness" of a cutting edge using an Electron microscope. The not unreasonable assumption being the thinner the micron size width of an edge the easier it cuts.

    Once this is known the emphasis then shifts to which sharpening processes produces the least force needed to cut the filament.

    We should also bear in mind that the size of the edge is only one of many variables that involve working sharpness. For example, why bother producing sub micron edges if on the first cut the edge is reduced to that of a butter knife?

    Anyway, good on Rob for being nerdy enough to independently test this setup and particularly openly showing us on the forum what and how he is testing. I'm sure he won't mind me calling him a nerd because I am happy enough to be in the same boat. As some of you know I'm all for independent testing and challenging manufacturers claims especially in the area of dust collection. I don't think Rob expects anyone else to do these test but it wouldn't hurt if someone else did.

  9. #8
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    Hadn't that been addressed on the page 44 of The KN100 Operating Manual available at the Edge On Up library www.edgeonup.com/Library.html ?
    A quote:

    It is inevitable that comparisons will be drawn between BESS® certified test media and other monofilament fibers designed for different applications.
    These include monofilament thread, fibers, sutures, fishing line and leaders. Monofilament is made from Nylon, polyethylene, polypropylene, polyolefin etc.
    Edge On Up has tested most of these fibers and found them to be, largely, unsuitable for our purposes. None perform, in concert with the BESS®. Some may resemble the BESS® on the bottom end of the scale but miss badly in the middle or top and vice versa. None have the repeatability or precision of BESS® certified test media.

    However, should you find yourself in a bind (out of test media) and simply want to know if one edge is sharper than another then ordinary fishing line (we suggest fishing line because it is readily available but if you have polyethylene thread etc. on hand then use it) can suffice if your precision requirements are broad. You can use 4, 6, or 8 lb. line because it makes little difference in this case. It simply needs to be able to fit inside the small slots in the clamping shoe.
    Once started down this path, stick with one spool and one size line by one manufacturer (even different spools (batches) of the same size line and manufacturer can yield significantly different results).
    Remember, you are not trying to make comparisons with the BESS®, you are simply trying to compare one edge to another.

  10. #9
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    How are you applying the force and how are you capturing the max load before it cuts through?

  11. #10
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    By hand and by eye. Very carefully, I have a couple of wounds for my efforts.
    Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.

  12. #11
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    Quote Originally Posted by rob streeper View Post
    By hand and by eye. Very carefully, I have a couple of wounds for my efforts.
    How do you know you are testing the same point to within the width of the line every time?

  13. #12
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    There is nothing wrong with similar in-house self-made systems, except not being able to communicate your sharpness results to others.

    BESS is a standard shared around the globe. We can make a sharpness test in our workshop in Australia and have the results understood in the US, the UK, Japan, anywhere.
    Communicating sharpness by a standard number benefits everyone even if they do not own an instrument.
    E.g. consumers would rather see a BESS number next to an electric sharpener, than marketing allegations of how sharp it makes your knife.

  14. #13
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    Quote Originally Posted by BobL View Post
    How do you know you are testing the same point to within the width of the line every time?
    I don't. It was apparent to me that the incident angle at which the blade intersects the filament makes a difference. Droop in the filament had a big effect. Preventing the blade from sawing the filament is also important. I can see a number of improvements that can be made to the BESS jigs / systems to improve repeatability.
    Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.

  15. #14
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    Quote Originally Posted by KnifeGrinders View Post

    BESS is a standard shared around the globe.
    Communicating sharpness by a standard number benefits everyone even if they do not own an instrument.
    I'm not sure that 'shared' and 'communicating' are appropriate words.
    Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.

  16. #15
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    Let me take this occasion to apologize for unfortunate mistake I typed in my earlier post regarding the BESS Score to Edge Width correlation.

    Correct are Mike Brubacher's findings, summarized in the "The Science Behind Edge On Up Instrumentation and BESS Test Media" section of the "Support Document for All Edge Tester Models" available in the EdgeOnUp library.
    These are somewhat more detailed in our post BESS Score to Edge Width correlation in the lower BESS scale

    An excerpt from my article in the Australian Knife Magazine can be read here: BESS SCORES IN TRADITIONAL SHARPNESS TESTS

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