How we check the quality of sharpening

wootzblade said:
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Thanks. I wonder why he uses the clips when they are not BESS certified? But they do seem to work well. I've been enjoying my PT50A, but I realize that it measures push cutting. I also use my 2" HD strap tester that I made. I can tell if a blade is sharp by how well it cuts the 2" HD Polypropylene Webbing or HD Nylon straps. Stropping does improve the edge with the PT50A, but I don't notice much if any difference to how well the edge cuts the straps. This is interesting though and I enjoy testing the edges.

Strap Holder-8a.jpg
 
Robert, pre-tensioned clips are better for videos for a number of reasons. Under 100 BESS the clips score the same as the BESS-certified test line anyway.
 
Jason B. said:
My thumb, lol.

I score in the teens or less on a BESS with my normal edge so for me its a bit inaccurate.
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Do you mean thumbnail? I enjoy cutting strips in my strap holder. But the PT50A actually puts a number on it, which is pretty cool, though it is a push-cut tester.
 
Pad of my thumb and "feel" the edge, like a Carter three finger test but with one finger. Place finger on edge and let it bite a little by moving your finger. Not enough movement to see, just to feel. 30 years of feeling edges this way and I can tell you things about a cutting edge most would need a microscope for.
 
Jason B. said:
Pad of my thumb and "feel" the edge, like a Carter three finger test but with one finger. Place finger on edge and let it bite a little by moving your finger. Not enough movement to see, just to feel. 30 years of feeling edges this way and I can tell you things about a cutting edge most would need a microscope for.
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I don't doubt you. I feel edges also, usually with two or three fingers but sometimes with my thumb.
 
Jason B. said:
Pad of my thumb and "feel" the edge, like a Carter three finger test but with one finger. Place finger on edge and let it bite a little by moving your finger. Not enough movement to see, just to feel. 30 years of feeling edges this way and I can tell you things about a cutting edge most would need a microscope for.
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How am I supposed to show sharpness in a video by a finger feel?

Under 100 BESS the pre-tensioned clips and BESS-certified test line score the same. E.g. Mike Brubacher scores on a new Gillette razor 50 BESS and Feather razor 30 BESS using the test line - and the same they score using clips in testing done by Chase Anderson at Refined Shave https://www.refinedshave.com/razor-blade-sharpness-testing
My tests of knife edges under 100 BESS show negligible difference of 1-3 BESS between the line and the clips. I start seeing a tangible difference between them on edges that score over 120 BESS.
The pre-tensioned clips are better for documenting events in a video, because rule out falsification of the sharpness score by over-tensioning the test line.

The Victorinox SWIBO Chef's knife in my video is sharpened at 12 dps and shows 61 BESS before and after the 2kg impact, and this is really impressive how strong a cleanly deburred edge is.
We filmed this episode by a single long shot.
A new Gillette razor scores 50 BESS, but of course is nowhere near as strong as the knife edge.

Key to the edge longevity, to the lasting razor edge on your knife, is to clean it of all the metal deformed in grinding.
 
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wootzblade wootzblade at 9:50 you say/write "So, in the test by stropping, no change is positive, while improved sharpness is negative as it tells of the wire edge and bad sharpening methods."

What if stropping on plain leather is intentionally used to remove the wire edge? Is this still indicative of bad sharpening methods?
 
Alberta Ed said:
Really sharp is when you see blood before you feel the cut.:D
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Or even when you don't see blood. I found a slice on my right index finger yesterday that I didn't even know was there. It wasn't deep enough to bleed and I didn't feel it when it happened.
 
000Robert said:
Or even when you don't see blood. I found a slice on my right index finger yesterday that I didn't even know was there. It wasn't deep enough to bleed and I didn't feel it when it happened.
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I keep a few of those at all times, but usually do feel the ones that bleed.
 
wootzblade said:
How am I supposed to show sharpness in a video by a finger feel?

Under 100 BESS the pre-tensioned clips and BESS-certified test line score the same. E.g. Mike Brubacher scores on a new Gillette razor 50 BESS and Feather razor 30 BESS using the test line - and the same they score using clips in testing done by Chase Anderson at Refined Shave https://www.refinedshave.com/razor-blade-sharpness-testing
My tests of knife edges under 100 BESS show negligible difference of 1-3 BESS between the line and the clips. I start seeing a tangible difference between them on edges that score over 120 BESS.
The pre-tensioned clips are better for documenting events in a video, because rule out falsification of the sharpness score by over-tensioning the test line.

The Victorinox SWIBO Chef's knife in my video is sharpened at 12 dps and shows 61 BESS before and after the 2kg impact, and this is really impressive how strong a cleanly deburred edge is.
We filmed this episode by a single long shot.
A new Gillette razor scores 50 BESS, but of course is nowhere near as strong as the knife edge.

Key to the edge longevity, to the lasting razor edge on your knife, is to clean it of all the metal deformed in grinding.
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Most people cut paper so, IDK.

What I do know is that a score of 60 or higher on a BESS is an edge I would consider "going dull". I was also one of the original testers for the BESS and you can look up the thread detailing some of my testing. The testing media and test itself can be "tricked" with various sharpening methods and stropping techniques so I wrote it off as inaccurate on a professional level. It may work ok to give baseline sharpness numbers to the average knife nut, but that's not me.

I hate to brag or boast of my sharpening skill but my edges are simply sharper than what 90% of most people can do. Its for this reason I simply best the BESS, I am better than the test and can create knives sharper than the test has a score for. So with that, I find the testing method and media used for testing to be flawed.

Here is something I tell everyone about "sharpness", kinda how I define it.

Sharpness is a perception that is only as good as your greatest experience.

IMO, you cannot put a number on sharpness, too many variables.
 
Mr.Wizard said:
If it's not a trade secret what is your sequence to get that level of sharpness?
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Grinding a very precise bevel to a very fine apex that is Clean. Having a clean even bevel is what usually keeps people from having sharp knives.

When you sharpen, look closer, so close you can see individual grind lines and bits of burr. This should also happen every handful of passes on a stone. A lot happens in a short time and if you miss out on what is happening you have moved from sharpening to making sharpening mistakes, and as we all know, you cant put the steel back on.

And no matter what anyone says, buy good stones.
 
Jason B. said:
My thumb, lol.

I score in the teens or less on a BESS with my normal edge so for me its a bit inaccurate.
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I recall the original wring-out getting s110v to score in the teens after stropping the crap out of it w/ silicon carbide. The edge was nothing I would have taken $ for but it performed great on the test. Most of mine in the 30s-40s on average with the methods I was using at the time, that was 6 years ago...

https://www.bladeforums.com/threads/edge-sharpness-tester.1285538/

Personally I use visual inspection, three finger, wave through newsprint or financial prospectus paper - done. If I'm using a standard progression I don't test any further, might not even bother with a paper cut test. If you have a system(s) that is consistent you should reach a point where proof testing isn't really necessary.

If trying out a new stone or done something different in the process I might test to make sure it will treetop some hair - my arms and legs aren't hairy enough to do that with every knife!
 
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