07-02-2018, 04:49 PM
(This post was last modified: 07-02-2018, 05:00 PM by KnifeGrinders.)
Cool illustration to what we know, Cyrano.
We know that diamond crystals leave behind deep narrow scratches while aluminium oxide shallow - you show that;
we know that the burr worsens BESS reading rather than the coarse apex - you show that.
You've put the right accent where those new to BESS tend to misinterpret the tester readings - a bad BESS score is more often indicative of a burr rather than of a not refined edge. Now I know that the BESS score of 350-700 I get on repeated sharpness tests of the same edge is indicative of the feather or foil burr, but when I was only starting to use the sharpness tester, I thought I hadn't thinned the apex and aimed my efforts to refining the edge where I should have to deburr it better.
Nowadays when I see a BESS reading of around 200, I read it as the wire burr.
"* I was surprised at the BESS values associated with the burrs before any stropping (582, 589, 416). I expected values much higher." - I'd suggest this is thanks to the decent steel in your knife, in the lower steels the burr gives higher readings.
"* My second set of stropping passes appears to have been effective at removing all residual burr.![[Image: smile.png]](http://bessex.com/forum/images/smilies/smile.png)
It also appears to have been effective at rounding the edge. ![[Image: sad.png]](http://bessex.com/forum/images/smilies/sad.png)
" - love this part, but the reading you see does not necessarily mean you've rounded the apex - it is rather expected, and I explain why.
Using Tormek honing paste which particles average 3 micron in size, and Todd Simpson's observation that "grit size and the scratch size are related by about an order of magnitude" (scienceofsharp.wordpress.com) we shall expect edge refinement to 0.3+ micron which is around 150+ BESS.
From my experience, I get better sharpness when honing with the Tormek paste by not applying the fresh paste and thus honing on the "worn" paste known to break down to smaller particles (they say down to 1 micron); also the leather wheel diameter differs by a few decimals on the same wheel in its different points and to avoid rounding the apex I hone at an angle little shallower than what the edge has been ground at.
We know that diamond crystals leave behind deep narrow scratches while aluminium oxide shallow - you show that;
we know that the burr worsens BESS reading rather than the coarse apex - you show that.
You've put the right accent where those new to BESS tend to misinterpret the tester readings - a bad BESS score is more often indicative of a burr rather than of a not refined edge. Now I know that the BESS score of 350-700 I get on repeated sharpness tests of the same edge is indicative of the feather or foil burr, but when I was only starting to use the sharpness tester, I thought I hadn't thinned the apex and aimed my efforts to refining the edge where I should have to deburr it better.
Nowadays when I see a BESS reading of around 200, I read it as the wire burr.
"* I was surprised at the BESS values associated with the burrs before any stropping (582, 589, 416). I expected values much higher." - I'd suggest this is thanks to the decent steel in your knife, in the lower steels the burr gives higher readings.
"* My second set of stropping passes appears to have been effective at removing all residual burr.
It also appears to have been effective at rounding the edge. " - love this part, but the reading you see does not necessarily mean you've rounded the apex - it is rather expected, and I explain why.Using Tormek honing paste which particles average 3 micron in size, and Todd Simpson's observation that "grit size and the scratch size are related by about an order of magnitude" (scienceofsharp.wordpress.com) we shall expect edge refinement to 0.3+ micron which is around 150+ BESS.
From my experience, I get better sharpness when honing with the Tormek paste by not applying the fresh paste and thus honing on the "worn" paste known to break down to smaller particles (they say down to 1 micron); also the leather wheel diameter differs by a few decimals on the same wheel in its different points and to avoid rounding the apex I hone at an angle little shallower than what the edge has been ground at.
http://knifeGrinders.com.au