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Sharpness Chart - KnifeGrinders - 11-25-2017
FYI, we've added a sharpness chart to the Sharpening Resources section of our website knifeGrinders.com.au
Includes data for all traditional sharpness tests.
RE: Sharpness Chart - Rupert Lucius - 11-25-2017
KnifeGrinders Sharpness Chart - http://knifegrinders.com.au/Manuals/Sharpness_Chart.pdf
Consider placing in EOU Product Videos & Documents?
Thanks
Rupert
RE: Sharpness Chart - EOU - 11-25-2017
Thank you KnifeGrinders and that's a good thought Mr. Rupert. With KnifeGrinders blessing we'll make it happen!
RE: Sharpness Chart - KnifeGrinders - 11-28-2017
Cigarette paper test - slice the edge furthest from fingers holding the cigarette paper, then push-cut down.
Becomes possible at 30 BESS or 0.06 micron edge, but cleanly performs only at 20 BESS or 0.04 micron edge.
This one is a highly precise test due to standardized "test media", and I replaced with it the toilet paper test in the sharpness chart on our website Sharpness Chart >>
I never took that single ply toilet paper or facial tissue tests seriously anyway.
RE: Sharpness Chart - Jan - 11-29-2017
KG, thanks for sharing your very useful sharpness chart. Appreciated.
The Australian Tally Ho rolling paper is really ultra-thin test medium! I think it weighs only 4 grams per metre square. If I am correct the paper thickness is about 5 microns (≈ 0.0002") only.
For comparison, human hair thickness is between 50 and 100 microns (≈ 0.002 to 0.004"). So, human hair is at least ten times thicker than the ultra-thin Tally Ho rolling paper.
Some sharpeners in this country use for knife sharpness testing standard light weight rolling paper which has about 12 grams per metre square, so it is three times thicker than your test medium. I have seen a video where very sharp/shaving sharp knife cuts this paper, but in my opinion it was not a quite clean push cut.
Jan
RE: Sharpness Chart - KnifeGrinders - 11-30-2017
(11-29-2017, 06:17 AM)Jan Wrote: KG, thanks for sharing your very useful sharpness chart. Appreciated.
The Australian Tally Ho rolling paper is really ultra-thin test medium! I think it weighs only 4 grams per metre square. If I am correct the paper thickness is about 5 microns (≈ 0.0002") only.
For comparison, human hair thickness is between 50 and 100 microns (≈ 0.002 to 0.004"). So, human hair is at least ten times thicker than the ultra-thin Tally Ho rolling paper.
Some sharpeners in this country use for knife sharpness testing standard light weight rolling paper which has about 12 grams per metre square, so it is three times thicker than your test medium. I have seen a video where very sharp/shaving sharp knife cuts this paper, but in my opinion it was not a quite clean push cut.
Jan
Very interesting.
No wonder this Tally Ho paper test requires the same level of keenness as the top hanging hair tests.
Any chance you can remember the source for its thickness being about 5 microns?
Thank you, Vadim
RE: Sharpness Chart - Jan - 11-30-2017
(11-30-2017, 02:25 AM)KnifeGrinder Wrote: Very interesting.
No wonder this Tally Ho paper test requires the same level of keenness as the top hanging hair tests.
Any chance you can remember the source for its thickness being about 5 microns?
Thank you, Vadim
Mr. Vadim,
The Tally Ho paper thickness of some 5 microns is not from internet, I have calculated it assuming the rolling paper volume density 750 kg/m³.
The formula is:
paper thickness (in microns) = 1 000 * paper weight (in g/m²) / paper density (in kg/m³) = 1000*4 / 750 ≈ 5 microns.
Jan
RE: Sharpness Chart - KnifeGrinders - 12-16-2017
The Sharpness Chart has been updated.
RE: Sharpness Chart - Rupert Lucius - 12-16-2017
(12-16-2017, 05:06 PM)KnifeGrinders Wrote: The Sharpness Chart has been updated.
My hope is that you will give Mike permission to make it a part of this Forum - http://knifegrinders.com.au/Manuals/Sharpness_Chart.pdf
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RE: Sharpness Chart - KnifeGrinders - 12-17-2017
Rupert, thank you and appreciate your kind words and support of the Sharpness Chart.
Having it posted on the Bladeforums helped reveal its weak spots - that have been corrected.
Thanks for their feedback even I myself began understanding what the heck I wrote in that chart.
Sharpness classification by BESS score has been met with overall acceptance in the Australian and the US knife communities -
the fact that the bladeforums.com pinned the Chart at the top of their Maintenance... forum speaks for itself
https://bladeforums.com/forums/maintenance-tinkering-embellishment.794