What do you guys think about this sharpness tester.

[Stacy E. Apelt - Bladesmith]

They fall out.

 

[Stromberg Knives]

Somewhere on this forum exist topic about that BESS numbers and machine for measurement , opened from one guy from Australia , I think . He managed to sharpen knife to be able to push cut cigarette papir in some distance from holding point... Seeing that, I take it as a challenge to do same .It was not easy task at all , but in the end I succeed ...I did not have exactly the same paper so I use what I found here but that don t matter .Do you know how long last that kind of sharpness on edge on my knife ? Zero time ! Than my light go on and I take new Gillette and make several short cut in cardboard .................and I check sharpness .... and that was eye opener not to lose more my time with zillion BSSS numbers of sharpness. My point is / I have no idea how sharp is 150BSSS edge/ that can be maybe disadvantage to you .Customer will be very happy how sharp is his new knife after first try .. . . and very soon will be disappointed , why my new knife don t cut like yesterday ?? But that knife is still very sharp /I call it working sharpness/which edge will hold for long time , depend on steel how long of course . . .
I found that topic . . .. . https://www.bladeforums.com/threads/sharpness-chart.1535016/

Yes, I'm very well aware of the difference between a showroom edge and a everyday working edge. The ridiculously sharp edges will lose a substantial amount of sharpness even during non use (for example overnight) due to oxidation and other fancy chemical processes I know nothing about.

As I pointed out, I'm interested in consistency. That does not equal the sharpest possible edge. My 150 BESS edges are usually produced with a 240 grit AO belt and carefully stropped on clean leather. I don't want it polished. They edges are very sharp and you can feel the toothiness compared to a polished edge, which excels at push cutting paper, but I seldom push cut paper with my knives in real life.

Here's a sharpness chart the Australian gentleman put together: http://knifegrinders.com.au/Manuals/Sharpness_Chart.pdf

I'm also very well aware of the fact that my 150 BESS edge pretty quickly will degrade to about 200-250 BESS, and then stay there for some time (how long depending on hardness, angle, steel etc). So even if I choose to send out my knife with a sharpness of 250 BESS, at least I have a more consistent way of testing it than my earlier methods (three finger test, shaving arm hair etc).

For more information and some practical testing:

 

[Stromberg Knives]

Since you own one and have used it a good bit, perhaps you can tell us if there is any difference in edge geometry. Using the same style of blade, one with a 10⁰ per side bevel, other with perhaps 20⁰ (or 30?) per side bevel, is there any difference is the sharpness reading? This would be assuming both blades were sharpened to the very sharpest edge possible.

In my opinion it's possible to obtain an incredible level of measurable sharpness (levels that are more of a gimmick than anywhere close to practical) regardless of angle and even steel. But you do have to sacrifice (pretty major) things like edge/sharpness retention und so weiter.

 

[JG Custom Metal Works]

Somewhere on this forum exist topic about that BESS numbers and machine for measurement , opened from one guy from Australia , I think . He managed to sharpen knife to be able to push cut cigarette papir in some distance from holding point... Seeing that, I take it as a challenge to do same .It was not easy task at all , but in the end I succeed ...I did not have exactly the same paper so I use what I found here but that don t matter .Do you know how long last that kind of sharpness on edge on my knife ? Zero time ! Than my light go on and I take new Gillette and make several short cut in cardboard .................and I check sharpness .... and that was eye opener not to lose more my time with zillion BSSS numbers of sharpness. My point is / I have no idea how sharp is 150BSSS edge/ that can be maybe disadvantage to you .Customer will be very happy how sharp is his new knife after first try .. . . and very soon will be disappointed , why my new knife don t cut like yesterday ?? But that knife is still very sharp /I call it working sharpness/which edge will hold for long time , depend on steel how long of course . . .
I found that topic . . .. . https://www.bladeforums.com/threads/sharpness-chart.1535016/

You’re arguing against a point no one is making. You’re going on about edge retention and the sharpness tester doesn’t measure “sharpness” as it pertains to edge retention. It measures “sharpness” as it pertains to edge geometry/acuity(IMO). Of course edge geometry effects edge retention, but this “sharpness” tester doesn’t assess value either way in that regard. It merely measures an edges ability to cut the medium. It doesn’t say, “it cuts it very easily, so that’s good!” That’s a determination the user/maker will have to determine, given the purpose of the blade. I mean look at their chart. They have the razor listed as being in the highest “sharpness” range for their measurements/scale. Do you think anyone is making the case that a razor blade, and it’s geometry/acuity is best for every knife? Lol. Because that’s what you’re arguing against, and no one is making that argument. I suppose if you want to keep ranting on abrasively, stating obvious facts, arguing against a claim no one is making, that’s your prerogative.

From the way I see it, what this device measures is the acuity/geometry of an edge. Because THAT is what cuts. It’s even reflected in their chart. Of course the level of which the edge is refined has bearing over an edges sharpness, but with all things being equal, and IMO to get an accurate reading, your edge must be refined(sharpened to an even bevel apex with the burr completely removed). The way I see it, this tester assumes that is in order. Therefor edge refinement would just be constant and not having any bearing over the measurement, leaving acuity/geometry being what’s measured. So, you’d really just be confirming your sharpening angle. But if your method of sharpening is measured and precise in regards to the angle of the bevel, I don’t really see the need for one of these things. For instance, if you measure the edge angles with an angle cube or angle finder(I use both when putting my edges on).

I suppose, you could make the case that thickness behind the edge would come into play, but even with that, common sense applies. What I mean by that is, you aren’t going to have a .040” thick edge on a blade and put a 12 degree per side edge bevel on it. If you’re going to put an edge bevel that acute on a knife, like with a chef knife, you’re going to want to have it thinned down to at least .015”( I thin my chef knives down to zero).

With all this in mind, and in regards to edge retention, there would be times when you would want a higher BESS rating(less “sharp”). Because that would reflect a more obtuse edge, which would be more conducive to edge retention when used for highly abrasive tasks like chopping. A more obtuse edge angle would be less “sharp,” but if it’s a blade/edge that will need to stand up to impacts, it would be appropriate. That is a value attributed by the user/maker and is outside the purview of this “sharpness” tester.

Bottom line, it’s widely known what edge angles are good for certain tasks. Whether it be a chopper with an obtuse edge, a super acute straight razor, or anything in between. As long as your method for putting an edge bevel on your knives is measurable, accurate, and repeatable, the tester isn’t needed IMO. It’s an answer to a question that no one is really asking. Or perhaps an answer to a question people don’t NEED to be asking.