12-30-2017, 02:28 AM
(This post was last modified: 12-30-2017, 04:59 AM by KnifeGrinders.)
To be absolutely honest, I didn't take that wire edge quest out of curiosity.
I wish I had - before my sharpening service got the first reject.
A customer returned his S30V Sebenza that I thought I had put a perfect edge on, because from hair-splitting it turned to blunt in less than 10 cuts. He cut some food on a plate, and this little stress turned the edge unusable.
The wire burr image you see above is of his Sebenza that I took in a desperate attempt to understand WTF was going on.
On a straight razor this wire burr just breaks and falls off as you start shaving, however with modern CPM steels it just bends and stays there.
To make things worse, an unsophisticated customer cannot strop it away himself, because S30V is already at the limit of the Cromium Oxide strops, for anything harder you need diamonds or CBN.
The tiny wire along the apex turns into a huge problem with the high-end blades.
And when high-end knives make a good part of your sharpening business, it threats the business.
I had been looking for an indicator of the wire burr without taking every blade under microscope, till I found out this 20 BESS threshold.
Nowadays I will not return the customer his sharpened classy knife until retest it in 10 hours after sharpening and see a score differing by less than 20 BESS.
The near esoteric revelations by Mike's sharpness tester explain the unseen that otherwise would have eluded sharpeners' comprehension.
I wish I had - before my sharpening service got the first reject.
A customer returned his S30V Sebenza that I thought I had put a perfect edge on, because from hair-splitting it turned to blunt in less than 10 cuts. He cut some food on a plate, and this little stress turned the edge unusable.
The wire burr image you see above is of his Sebenza that I took in a desperate attempt to understand WTF was going on.
On a straight razor this wire burr just breaks and falls off as you start shaving, however with modern CPM steels it just bends and stays there.
To make things worse, an unsophisticated customer cannot strop it away himself, because S30V is already at the limit of the Cromium Oxide strops, for anything harder you need diamonds or CBN.
The tiny wire along the apex turns into a huge problem with the high-end blades.
And when high-end knives make a good part of your sharpening business, it threats the business.
I had been looking for an indicator of the wire burr without taking every blade under microscope, till I found out this 20 BESS threshold.
Nowadays I will not return the customer his sharpened classy knife until retest it in 10 hours after sharpening and see a score differing by less than 20 BESS.
The near esoteric revelations by Mike's sharpness tester explain the unseen that otherwise would have eluded sharpeners' comprehension.
http://knifeGrinders.com.au