Edge Sharpness Tester

[Ankerson]

D2 is kind of a strange bird depending on how high the RC has been pushed. An inverted bell curve with the high water mark at 1K jibes with how I prefer to sharpen that steel, but is still mysterious that it responded with a pretty definitive drift. Maybe re-run the prep, avoiding the films and strops and just take it as high as possible with stones/plates. When the carbides are that easily seen standing out of the matrix I have to suspect on some level the softer media is dragging it down in some respects (#s began climbing with film usage/carbide excavation).

Edit to add:
Is this exact effect that has me avoiding all but the most superficial stropping on high carbide steels in general and D2 in particular, even with diamonds.

Kinda goes to what I have telling people for awhile now.

I don't strop after sharpening at all.

I knock off the wire edge/burr on hard plastic or wood by cutting into it then do my light passes as needed.

If one really feels the need to strop only do like one or two passes then STOP!!!!!!!!.

Touch ups are different however, but less is better, do just enough to bring the edge back then STOP!!!!!

I don't normally get involved in the sharpening threads for various reasons however.

 

[REK Knives]

Josh,

I see burr present on the edge and in photo #2 you can see how it has stood straight after being stropped on a pant leg.

You should be able to get the edges a bit cleaner using diamonds, do you do any distressing of the edge? Cork, soft wood, felt block?

D2 is kind of a strange bird depending on how high the RC has been pushed. An inverted bell curve with the high water mark at 1K jibes with how I prefer to sharpen that steel, but is still mysterious that it responded with a pretty definitive drift. Maybe re-run the prep, avoiding the films and strops and just take it as high as possible with stones/plates. When the carbides are that easily seen standing out of the matrix I have to suspect on some level the softer media is dragging it down in some respects (#s began climbing with film usage/carbide excavation).

Edit to add:
Is this exact effect that has me avoiding all but the most superficial stropping on high carbide steels in general and D2 in particular, even with diamonds.

Good points. On each check I checked the edges in three separate spots (heel, midway, and start of belly) each time and those are the average numbers. I also experienced this on the first knife to a lesser extent... I think that was elmax (see below)

The reason I am confused is because both the 200 and 1k grit levels tested the same, at 50 grams, even though the 200 edge would barely shave hair and the 1k edge was popping it off (on both sides). What was really interesting was when I got the the 1um level it took a whopping 90 grams to sever the test media! And this same edge was hair whittling at this stage. Post stropping I saw better results with it dropping down to 25 grams (at this stage it was passing HHT-4).

 

[HeavyHanded]

Kinda goes to what I have telling people for awhile now.

I don't strop after sharpening at all.

I knock off the wire edge/burr on hard plastic or wood by cutting into it then do my light passes as needed.

If one really feels the need to strop only do like one or two passes then STOP!!!!!!!!.

Touch ups are different however, but less is better, do just enough to bring the edge back then STOP!!!!!

I don't normally get involved in the sharpening threads for various reasons however.

Most that are familiar with my views on sharpening etc would probably find this somewhat at odds with a lot of what I profess. I only avoid stropping with high carbide steels at any level of finish and toothy edges on all steel types. Even then I'll strop on paper, but lightly - just enough to remove any small burrs or at least stand/polish them up so I can remove them more thoroughly on the stone with a leading pass.

Is not a question of what can work, but of what the steel seems to prefer, especially as it ages in - opinions will vary. Josh's pics show what I've seen through my microscope as well - the effect of carbide excavation is not eliminated by using diamond compounds, even on hard surfaces like balsa though to the naked eye it polished up great!

On low carbide stainless and carbon steel taken to a finer finish, I will almost always top off with some sort of backhoning on a softer stone or stropping on my Washboard. Heck, I often use my Washboard AS my finer hone, but then I don't believe it is representative of most strops of any composition - not many (none other that I know of) can physically burnish steel to the degree it can using only paper.

There are just too many variables when it comes to stropping, I avoid any blanket statements except when it comes to those high carbide steels. YMMV

 

[Komitadjie]

Josh, what scope did you use to take those pictures? I'd assume a USB-scope of some kind, but that's some darn nice quality.

 

[Omega Leather Works]

I'm really looking forward to trying this when it arrives.

Only thing, I haven't yet figured out is how to add value to the testing done thus far. I don't have a whole lot of high end sharpening kit, nor do I have a bevy of super high end knives to sample from. I think I'll need to devise a plan to show common mistakes in sharpening, or the efficacy of the strop for general maintenance. Which is "better" the nap, or skin side, etc. That kind of thing. A focus on generalization will be necessary, but this is supposed to be a precision instrument so...

In any case, I'm really liking what I'm seeing so far! Big thanks to the powers that be for including me in this testing round. Now, as soon as I get out of the hospital I'll poke at the tool and read tfm.

 

[Ankerson]

I'm really looking forward to trying this when it arrives.

Only thing, I haven't yet figured out is how to add value to the testing done thus far. I don't have a whole lot of high end sharpening kit, nor do I have a bevy of super high end knives to sample from. I think I'll need to devise a plan to show common mistakes in sharpening, or the efficacy of the strop for general maintenance. Which is "better" the nap, or skin side, etc. That kind of thing. A focus on generalization will be necessary, but this is supposed to be a precision instrument so...

In any case, I'm really liking what I'm seeing so far! Big thanks to the powers that be for including me in this testing round. Now, as soon as I get out of the hospital I'll poke at the tool and read tfm.

Don't need any high dollar sharpening stuff.

The stones I use are like $5 a piece that I use for my Edge Pro, the Congress Mold Masters, Silicon Carbide.

Then the Norton Crystolon bench Stones (Silicon Carbide) I use are like $18 a piece for the 8" x 3" ones I have.

My educated thumb has served me well over the years and that has been confirmed by the Sharpness Tester.

But then sharpening knives for 40 years helps I suppose.

 

[bpeezer]

My educated thumb has served me well over the years and that has been confirmed by the Sharpness Tester.

Glad to hear it works, that has become my favorite test!

I am very interested in this sharpness tester though...just paid for a surgery, but when I can afford one I'll have to pick one of these up

 

[bodog]

Ankerson, what are the findings you see on a fresh razor blade, 50 +/- too?

 

[Twindog]

I believe that the testers can be consistent in maintaining a reasonably constant thread tension, enough to give good consistency on reported BESS scores.

However, I just tested the cutting pressure needed to cut a lightly tensioned thread compared to cutting a highly tensioned thread. Big difference. The higher the tension, the better the cutting score.

So for the BESS score to be meaningful to anyone but that particular tester, string tension has to be held constant.

I'd also guess that coarse edges would do better with highly tensioned string.

 

[lynus]

No one has said if they would shell out the $150+ it would cost to buy this tool.

My free test...
Does it feel sharp to me?
Will it cut what I need it to cut?

A yes to both of these earns you a trip out of the house.

I'm not sure if I understand what any of you are trying accomplish?

 

[bodog]

No one has said if they would shell out the $150+ it would cost to buy this tool.

My free test...
Does it feel sharp to me?
Will it cut what I need it to cut?

A yes to both of these earns you a trip out of the house.

I'm not sure if I understand what any of you are trying accomplish?

A way to test how sharp a knife is and the subsequent dulling through use that can be reproduced by other people and give real rankings of just how sharp a knife can get and how sharp it stays through use.

 

[Rhinoknives1]

I'm really looking forward to trying this when it arrives.

Only thing, I haven't yet figured out is how to add value to the testing done thus far. I don't have a whole lot of high end sharpening kit, nor do I have a bevy of super high end knives to sample from. I think I'll need to devise a plan to show common mistakes in sharpening, or the efficacy of the strop for general maintenance. Which is "better" the nap, or skin side, etc. That kind of thing. A focus on generalization will be necessary, but this is supposed to be a precision instrument so...

In any case, I'm really liking what I'm seeing so far! Big thanks to the powers that be for including me in this testing round. Now, as soon as I get out of the hospital I'll poke at the tool and read tfm.

Anthony, Get well and get outa there! There are sick people in hospitals that can make you sick!

Don't need any high dollar sharpening stuff.

The stones I use are like $5 a piece that I use for my Edge Pro, the Congress Mold Masters, Silicon Carbide.

Then the Norton Crystolon bench Stones (Silicon Carbide) I use are like $18 a piece for the 8" x 3" ones I have.

My educated thumb has served me well over the years and that has been confirmed by the Sharpness Tester.

But then sharpening knives for 40 years helps I suppose.

I agree, the results of your sharpening are what matter, I've used the bottom of a coffee mug to sharpen old "Americana" knives knives at a cabin with fine results. My box arrived from Mike, I've played it with it some, I had a real busy Sat and a Farmers market Sunday with no let up in sight so I will do a few more tests as time allows. My first couple were just to put my toes in the water and see what was in front of me.

I believe that the testers can be consistent in maintaining a reasonably constant thread tension, enough to give good consistency on reported BESS scores.

However, I just tested the cutting pressure needed to cut a lightly tensioned thread compared to cutting a highly tensioned thread. Big difference. The higher the tension, the better the cutting score.

So for the BESS score to be meaningful to anyone but that particular tester, string tension has to be held constant.

I'd also guess that coarse edges would do better with highly tensioned string.

Those were some of my initial thoughts along with blade thickness just behind the cutting edge. Hmmm?

No one has said if they would shell out the $150+ it would cost to buy this tool.

My free test...
Does it feel sharp to me?
Will it cut what I need it to cut?

A yes to both of these earns you a trip out of the house.

I'm not sure if I understand what any of you are trying accomplish?

Well, most of the knives I sharpen are headed back into the house,

That's the idea of our testing. To see the merits and detractors of these testing units that have been graciously loaned to us.

More later!

 

[REK Knives]

Josh, what scope did you use to take those pictures? I'd assume a USB-scope of some kind, but that's some darn nice quality.

Hey Dan, it was a Dinolite discontinued model now that gets to 230x... I love the quality Dinolite produces, but they have way better ones out there nowadays! mine is about 3 years old.

Most that are familiar with my views on sharpening etc would probably find this somewhat at odds with a lot of what I profess. I only avoid stropping with high carbide steels at any level of finish and toothy edges on all steel types. Even then I'll strop on paper, but lightly - just enough to remove any small burrs or at least stand/polish them up so I can remove them more thoroughly on the stone with a leading pass.

Is not a question of what can work, but of what the steel seems to prefer, especially as it ages in - opinions will vary. Josh's pics show what I've seen through my microscope as well - the effect of carbide excavation is not eliminated by using diamond compounds, even on hard surfaces like balsa though to the naked eye it polished up great!

On low carbide stainless and carbon steel taken to a finer finish, I will almost always top off with some sort of backhoning on a softer stone or stropping on my Washboard. Heck, I often use my Washboard AS my finer hone, but then I don't believe it is representative of most strops of any composition - not many (none other that I know of) can physically burnish steel to the degree it can using only paper.

There are just too many variables when it comes to stropping, I avoid any blanket statements except when it comes to those high carbide steels. YMMV

So is that what the little bumps are in the pics? Carbides poking out of the aggregate? Very interesting indeed...

I believe that the testers can be consistent in maintaining a reasonably constant thread tension, enough to give good consistency on reported BESS scores.

However, I just tested the cutting pressure needed to cut a lightly tensioned thread compared to cutting a highly tensioned thread. Big difference. The higher the tension, the better the cutting score.

So for the BESS score to be meaningful to anyone but that particular tester, string tension has to be held constant.

I'd also guess that coarse edges would do better with highly tensioned string.

Well the way it's designed is that the BESS thread is on a spool. So when you pull it up and through, and put tension on it, you cannot put too much tension or more will just come out of the spool. You are just supposed to pull it taught and then tighten the two nuts to clamp it in place, all the while holding the BESS thread with tension on it. You could overload the tension on it if you clamped the one nut first then pulled it tighter, but it does not seem to be a concern if you just hold the same tension while tightening the nuts.

 

[Jens Schuetz]

Just out of curiosity it would be cool to see a Glas and or Obsidian blade being tested.

 

[Ankerson]

Ankerson, what are the findings you see on a fresh razor blade, 50 +/- too?

Haven't done it yet, used the utility blade to get used to it.

 

[Ankerson]

I believe that the testers can be consistent in maintaining a reasonably constant thread tension, enough to give good consistency on reported BESS scores.

However, I just tested the cutting pressure needed to cut a lightly tensioned thread compared to cutting a highly tensioned thread. Big difference. The higher the tension, the better the cutting score.

So for the BESS score to be meaningful to anyone but that particular tester, string tension has to be held constant.

I'd also guess that coarse edges would do better with highly tensioned string.

The beauty of it is that if the testers aren't reasonably consistent the results will be all over the place so it forces us to be consistent.

This thing is so accurate and the measurement increments are so small, grams are VERY small that any screw up will be apparent right away.

And everyone will be using the same machine and or one that is BESS certified AND the same test media.

BESS is a universal standard.

Link here: http://www.bessu.org/

So in the end someone talking BESS numbers will be understood by others who are using the same.

 

[Omega Leather Works]

I'm really happy to see this tool getting consistent results. Bravo to the maker and testers.

I hope this becomes a universal measure for initial sharpness and data points for apex degradation.

This is fairly exciting!

 

[HeavyHanded]

I believe that the testers can be consistent in maintaining a reasonably constant thread tension, enough to give good consistency on reported BESS scores.

However, I just tested the cutting pressure needed to cut a lightly tensioned thread compared to cutting a highly tensioned thread. Big difference. The higher the tension, the better the cutting score.

So for the BESS score to be meaningful to anyone but that particular tester, string tension has to be held constant.

I'd also guess that coarse edges would do better with highly tensioned string.

A fish scale would fix any ambiguities - string tension should be somewhat standardized. Lock one side and pull to some nominal value that makes sense.

 

[Komitadjie]

Was a bit pressed for time last night, but I was able to start a testing series. I ran four of my favourite knives through my usual sharpening process on the Kalamazoo, and tested them within a few minutes of coming off the belts. The progression used was all Trizact for abrasives, A65, A16, A6, A3, followed by 1u Boron Carbide on a SurgiSharp leather belt, and .5u Chromium Oxide on a SurgiSharp belt. The edge is my normal working edge, and will shave armhair cleanly and easily with all four knives, and if I'm careful pass a low-level HHT. I can do somewhat better on the belts if I take more time, but I wanted to try my "normal" edge out and see how it looked.

Northstar EDC (3V steel, same knife tested in the previous series)
#1 = 86.0
#2 = 82.4
#3 = 86.2
AVG = 84.9

Spyderco Paramilitary 2 (same knife tested in the previous series)
#1 = 82.2
#2 = 81.1
#3 = 86.6
AVG = 83.3

BRKT Mini Canadian (A2 steel)
#1 = 108.2
#2 = 108.1
#3 = 109.2
AVG = 108.5

BRKT Saex Prototype (CPM-D2 steel)
#1 = 109.6 - Discarded this number, see more below
#2 = 123.4
#3 = 118.9
#4 = 121.7
AVG = 121.3


While I was testing the Seax, I noticed something interesting. I used up the media I had in the cup I use for "sifting" in the shot to the top cup on the test unit from the Mini Canadian test, and had to go to one of the little storage containers for a bit more. It took me perhaps ten seconds to reach for more mass, and in that time, the tester dropped on its own! Since I was not entirely sure what I had done there, I discarded that data point from my calculations, and completed the rest of the test series as planned. Since this struck me as something rather interesting, once I'd completed the test battery, I came back and made another pass at it. For this test, I chose the Seax (since it had displayed it once before already) and I chose a weight of 111 grams (since 111 grams is approximately 10 grams below the weight needed to cause a prompt media failure, according to the previous tests). My method for this test was to very, very carefully place the weight cup on top of the ram platform, then move my hand back to start a stop watch, and record when the ram head dropped.

The results of four tests are as follows:

7.3 seconds to cut
3.5 seconds to cut
4.2 seconds to cut
1.1 seconds to cut

I will have to play with this a bit more, I was not expecting to see that! I will also double-check my instrument again, with regard to ram mass. I am absolutely sure that my lock screw was fully disengaged for those tests. I also note that there was a reasonably steady downward trend in the time-to-cut, with no change in mass on the ram, or method of testing, that I have no idea of the cause for. I will play with this one more, I think. Would someone with a decent microscope like to give this a try, and see how it looks under magnification?

Finally upgraded to one of my good notebooks!

 

[stevebot]

Last night I stropped 4 of our kitchen knives that were not slicing tomatoes to my satisfaction. One tested at 102 - utility knife range. The other 3 tested at 38, 26 and 14. I double checked the last measurement. That is 14 including the cup - 8 for the cup and 6 gr. of shot. I'm happy.