This thorough test tells us that apex of the edge of the knife used in the test is not a clean steel, but the root of the burr - a weak apex that has been shaped from micro-fractured metal deformed in sharpening.
We cannot see the root of the burr under microscope, we need Scanning Electron Microscope for this.
The knife position remains unchanged through all the testing.
With repeated pressure of the test line on the same point, a micro-dent forms
![[Image: micro-dent.jpg]](http://knifegrinders.com.au/photos/micro-dent.jpg)
The bottom of this microdent is "mushroomed", widened - on SEM it looks like this:
![[Image: mushrooming.jpg]](http://knifegrinders.com.au/photos/mushrooming.jpg)
The wider becomes the bottom of the dent, the worse becomes the sharpness score.
BESS test line diameter is about 0.22mm, and under the same load it exerts more pressure per point, than the fishing line of 0.25mm diameter.
Because of that, the BESS line goes deeper into the root of the burr than the fishing line, and causes more widening at the bottom of the micro-dent.
This is the reason why the test shows faster worsening of the sharpness score of the BESS test line than the fishing line.
If the knife edge were of a clean steel, you would see the same little scatter in the sharpness score that you see in the Wilkinson razor.
Willy, Dr. Werner is finishing translation of my Knife Deburring book to German, email me at KG@knifeGrinders.com.au and I will send you the Deutsch book in PDF.
It explains the root of the burr and wire edge, and what they show on the BESS tester.
To me, your device is an advanced detector of the wire edge and root of the burr, and can be used to evaluate quality of the sharpening process.
Talking of the knife in the test, the initial score of 150 is an indicator of a residual burr on the edge. When with the repeated testing it worsens to 300, you should be able to see the micro-dent with a loupe - something similar to this:
![[Image: whire_edge_s.JPG]](http://knifegrinders.com.au/photos/whire_edge_s.JPG)
We cannot see the root of the burr under microscope, we need Scanning Electron Microscope for this.
The knife position remains unchanged through all the testing.
With repeated pressure of the test line on the same point, a micro-dent forms
The bottom of this microdent is "mushroomed", widened - on SEM it looks like this:
The wider becomes the bottom of the dent, the worse becomes the sharpness score.
BESS test line diameter is about 0.22mm, and under the same load it exerts more pressure per point, than the fishing line of 0.25mm diameter.
Because of that, the BESS line goes deeper into the root of the burr than the fishing line, and causes more widening at the bottom of the micro-dent.
This is the reason why the test shows faster worsening of the sharpness score of the BESS test line than the fishing line.
If the knife edge were of a clean steel, you would see the same little scatter in the sharpness score that you see in the Wilkinson razor.
Willy, Dr. Werner is finishing translation of my Knife Deburring book to German, email me at KG@knifeGrinders.com.au and I will send you the Deutsch book in PDF.
It explains the root of the burr and wire edge, and what they show on the BESS tester.
To me, your device is an advanced detector of the wire edge and root of the burr, and can be used to evaluate quality of the sharpening process.
Talking of the knife in the test, the initial score of 150 is an indicator of a residual burr on the edge. When with the repeated testing it worsens to 300, you should be able to see the micro-dent with a loupe - something similar to this:
http://knifeGrinders.com.au