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Thanks mate, done.
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Sharpness Chart
- Thread starter wootzblade
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The Sharpness Chart has got final edits.
I've added paper gsm (g/m2) as you asked - sales thermal paper is about half of the regular print paper, and the cigarette rolling paper is almost 5 times thinner.
Paper thickness can be calculated by formula:
paper thickness (in microns) = 1 000 * paper weight (in g/m²) / paper density (in kg/m³)
Thanks everyone for feedback, I've cleared a few things to myself.
Initially posted as a simple FYI, has turned into a fruitful discussion.
BTW my name is Vadim, while Wootz is a patterned crucible steel developed in India in the 6th century BC; I was so fascinated by it that spent a little fortune to get a few ancient wootz blades into my collection, and even used it for my forum nickname.
In a way, this advanced alloy contributed to Alexander the Great failure to conquer India. Lightweight and springy Indian tulwars outperformed ancient Greek swords in battles, and could chop through the Greek armor - amid battle the Greek had to straighten their bent swords, while wootz just went on.
The Chart is ready for this forum sticky, if the forum admin cares.
I've added paper gsm (g/m2) as you asked - sales thermal paper is about half of the regular print paper, and the cigarette rolling paper is almost 5 times thinner.
Paper thickness can be calculated by formula:
paper thickness (in microns) = 1 000 * paper weight (in g/m²) / paper density (in kg/m³)
Thanks everyone for feedback, I've cleared a few things to myself.
Initially posted as a simple FYI, has turned into a fruitful discussion.
BTW my name is Vadim, while Wootz is a patterned crucible steel developed in India in the 6th century BC; I was so fascinated by it that spent a little fortune to get a few ancient wootz blades into my collection, and even used it for my forum nickname.
In a way, this advanced alloy contributed to Alexander the Great failure to conquer India. Lightweight and springy Indian tulwars outperformed ancient Greek swords in battles, and could chop through the Greek armor - amid battle the Greek had to straighten their bent swords, while wootz just went on.
The Chart is ready for this forum sticky, if the forum admin cares.
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Agreed.Labels easily get misused as a description, I'd prefer if the labels were absolutely honest
cigarette paper Cross slice-start-push-cut:
cigarette paper Longitudinal slice-start-push-cut:
because slice to start then push cut the rest of the way is much easier than a push cut with no slice from the start
That assumes the knife is 90 degree to the paper (perpendicular) in all 3 axes
Speaking of papers, it would be useful to include paper thicknesses,
~0.0040 inch is ~100 microns average a4 printer/copy paper
~0.0020 inch is ~50 microns for phonebook or yellow pages paper
~0.0010 inch is ~25 microns for Tops cigarette rolling paper
~0.0005 inch is ~12 microns for OCB Hemp cigarette rolling paper
ref Re: Practical Ways to Evaluate Sharpeness
I clicked on that link (practical ways to evaluate sharpness) and was wondering the same thing one of the posters did: what did the person use to measure thickness.
My Mitutoya dial indicator, thickness gage, (range 0.01-5 mm) doesn't have the resolution to measure microns under 100µ. All I can tell is that my cigarette paper is <0.01 mm (and probably > 0.005 mm) . Same problem with the handheld micrometer. (The person doing the measuring in the "practical ways to evaluate sharpness" link used a micrometer. He didn't say what kind or if he was rounding up or down to get so many significant figures.)
So, I don't know how they are getting that many significant figures. I'm not saying it can't be done, just that I don't see it mentioned. Maybe I missed it?
Does anyone have exact measurements of the cigarette papers? Measured with equipment with the necessary resolution/precision?
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FWIW, I'd cast my vote for this too and ask that it be considered for a forum sticky. These informal, but more systematic, sharpness tests are really useful, even though admittedly not infallible and not 100% precise for those of us home users who don't have sophisticated measuring gear. I like the spirit of what this is trying to do: establish a consistent language and 'protocol' for determining degrees of sharpness. It'd be e a great idea to add this to a forum sticky, provided that folks can keep submitting new findings/info and it can keep getting updated when appropriate, as has been the case in this thread.
Either way, thanks for the work putting this together, and the openness to updating it as users give feedback.
wootzblade
, I pinged a mod, they added to sticky. FWIW, it'd be cool if somehow you could embed the info for your chart directly in the sticky thread (as opposed to pointing off to separate website). But up to you, it's your chart. 
Thanks again for putting it together, and open sourcing it.
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Have you asked yourself why sharpness of your knife deteriorates with time even if it does not cut anything?
One cause for this is oxidation that we sort of addressed in the footnote in our Chart.
Another is the wire burr - you can detect it only under a microscope.
Wire burr behavior had been described by Mike Brubacher in the KN100 Operating Manual, pages 39-42 at http://www.edgeonup.com/Library.html
What you read there is in line with what Todd S. found out and illustrated by SEM images on his scienceofsharp.wordpress.com
A continuous wire burr is seen as a structural part of the apex, folding to one side of the edge soon after sharpening; "foil burr" is just another name for the wire burr.
When straightened by steeling or stropping, it is your sharpest edge.
Deburred completely by high-angle stropping, i.e. at an angle larger than the edge angle, the edge will be less sharp initially, but stay sharp for longer as no burr rolling occurs with the knife use (well, at least in soft food cutting on an edge-friendly cutting board).
The BESS scores I get when I sharpen deliberately preserving the wire burr:
- immediately after sharpening 55-60;
- 2 hours later 80 - I attribute this worsening chiefly to oxidation, and to a lesser degree to the burr bending - the edge oxidation is known to worsen the score by 5-20 BESS;
- in 10 hours 115 BESS - due to the wire burr folding to one side.
By gently stropping this edge on a clean leather, after just 4 very light knife-weight alternating strokes, I get the sharpness score back to about 70-80 BESS - thanks to aligning the wire burr.
Mike B. says it takes 6-8 hours for the burr to spontaneously return to its rolled position due to the metal memory.
USB microscope image of the wire/foil burr
For comparison to the above, look at the same edge, but now completely deburred by fine honing on a paper wheel with a 0.5 micron abrasive at an angle +0.4 degree larger than the edge angle (e.g. honing a 15 dps edge at 15.4 degrees):
The BESS scores I get for the deburred edge:
- immediately after sharpening 65;
- 2 hours later 70;
- in 10 hours 70 BESS;
- next day 72 BESS - no deterioration with time.
***Testing Time !!!
In quest for the best deburring method - identical knives with diagnosed wire and foil/feather burrs waiting to be deburred on a paper wheel, rock-hard felt wheel, and leather wheel... to be then tested to compare effectiveness of the deburring methods...
... and the winner is...
Look for Knife Grinders' article on paper wheels study in the February issue of the US Sharpeners' Report and the wire/foil burr study in the April issue.
They summarise hundreds of tests we've done honing and deburring on paper, felt and leather at various angles, and with various fine abrasives.
One cause for this is oxidation that we sort of addressed in the footnote in our Chart.
Another is the wire burr - you can detect it only under a microscope.
Wire burr behavior had been described by Mike Brubacher in the KN100 Operating Manual, pages 39-42 at http://www.edgeonup.com/Library.html
What you read there is in line with what Todd S. found out and illustrated by SEM images on his scienceofsharp.wordpress.com
A continuous wire burr is seen as a structural part of the apex, folding to one side of the edge soon after sharpening; "foil burr" is just another name for the wire burr.
When straightened by steeling or stropping, it is your sharpest edge.
Deburred completely by high-angle stropping, i.e. at an angle larger than the edge angle, the edge will be less sharp initially, but stay sharp for longer as no burr rolling occurs with the knife use (well, at least in soft food cutting on an edge-friendly cutting board).
The BESS scores I get when I sharpen deliberately preserving the wire burr:
- immediately after sharpening 55-60;
- 2 hours later 80 - I attribute this worsening chiefly to oxidation, and to a lesser degree to the burr bending - the edge oxidation is known to worsen the score by 5-20 BESS;
- in 10 hours 115 BESS - due to the wire burr folding to one side.
By gently stropping this edge on a clean leather, after just 4 very light knife-weight alternating strokes, I get the sharpness score back to about 70-80 BESS - thanks to aligning the wire burr.
Mike B. says it takes 6-8 hours for the burr to spontaneously return to its rolled position due to the metal memory.
USB microscope image of the wire/foil burr
For comparison to the above, look at the same edge, but now completely deburred by fine honing on a paper wheel with a 0.5 micron abrasive at an angle +0.4 degree larger than the edge angle (e.g. honing a 15 dps edge at 15.4 degrees):
The BESS scores I get for the deburred edge:
- immediately after sharpening 65;
- 2 hours later 70;
- in 10 hours 70 BESS;
- next day 72 BESS - no deterioration with time.
***
In quest for the best deburring method - identical knives with diagnosed wire and foil/feather burrs waiting to be deburred on a paper wheel, rock-hard felt wheel, and leather wheel... to be then tested to compare effectiveness of the deburring methods...
... and the winner is...
Look for Knife Grinders' article on paper wheels study in the February issue of the US Sharpeners' Report and the wire/foil burr study in the April issue.
They summarise hundreds of tests we've done honing and deburring on paper, felt and leather at various angles, and with various fine abrasives.
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- Nov 19, 2014
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Thank you for the info,
wootzblade
If I understand correctly, you use the measurement of DE razor by ToddS as the single reference point to convert BESS to edge width (contact area) and assume a linear relationship between BESS and edge width.
It would be nice if you have a few more reference points up and down from the DE razor, as it is meaningless to extrapolate from a single point. I guess ToddS has measurements of other commercial razor blades, which are thicker than DE. Also, you can probably use a glass blade (or obsidian blade) as thinnest at 6~8 nm wide. Then, you can test if the relationship is linear over the range.
Or, do you already have these reference points, as you mentioned the linearity?
wootzblade
If I understand correctly, you use the measurement of DE razor by ToddS as the single reference point to convert BESS to edge width (contact area) and assume a linear relationship between BESS and edge width.
It would be nice if you have a few more reference points up and down from the DE razor, as it is meaningless to extrapolate from a single point. I guess ToddS has measurements of other commercial razor blades, which are thicker than DE. Also, you can probably use a glass blade (or obsidian blade) as thinnest at 6~8 nm wide. Then, you can test if the relationship is linear over the range.
Or, do you already have these reference points, as you mentioned the linearity?
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- Feb 24, 2014
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Not exactly so.
Personally, I do not own any data; the manufacturer Edge-On-Up is the source of information for us.
The edge sharpness tester inventor Mike Brubacher had carried out a study together with the Arizona State University SEM lab, and established the relationship between his instruments reading and edge apex width. Understandably, the raw research data will hardly ever become available online.
We distribute his instruments in Australia and New Zealand, and follow the manufacturer statement, as in the Sharpness Chart.
In this thread I give references to other sources available in the public domain chiefly for those new to BESS, as cross-referencing supposedly is convincing.
Another reason is that my own BSometer is always set at low threshold - for anything to pass it, it must be real and confirmed by independent sources.
Let me repeat myself, approximation is inherent to any method other than taking every edge under the SEM.
Yet to my knowledge, BESS is the only available for home use that provides us with this.
We should not take BESS scores as a conclusive data of the edge apex radius, however to a first approximation, as an idea +/- it's fine.
Most industrial users use them on a relative measurement basis, but the standard BESS scale makes possible the data comparison and exchange.
All the doubt in the world cannot alter fact - it works.
BESS edge sharpness testers reveal the unseen that eludes sharpeners' comprehension. And the sharpeners who've harnessed it have the best protocols.
Personally, I do not own any data; the manufacturer Edge-On-Up is the source of information for us.
The edge sharpness tester inventor Mike Brubacher had carried out a study together with the Arizona State University SEM lab, and established the relationship between his instruments reading and edge apex width. Understandably, the raw research data will hardly ever become available online.
We distribute his instruments in Australia and New Zealand, and follow the manufacturer statement, as in the Sharpness Chart.
In this thread I give references to other sources available in the public domain chiefly for those new to BESS, as cross-referencing supposedly is convincing.
Another reason is that my own BSometer is always set at low threshold - for anything to pass it, it must be real and confirmed by independent sources.
Let me repeat myself, approximation is inherent to any method other than taking every edge under the SEM.
Yet to my knowledge, BESS is the only available for home use that provides us with this.
We should not take BESS scores as a conclusive data of the edge apex radius, however to a first approximation, as an idea +/- it's fine.
Most industrial users use them on a relative measurement basis, but the standard BESS scale makes possible the data comparison and exchange.
All the doubt in the world cannot alter fact - it works.
BESS edge sharpness testers reveal the unseen that eludes sharpeners' comprehension. And the sharpeners who've harnessed it have the best protocols.
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- Sep 23, 2014
- Messages
- 1,287
Hi,
you did it too
0.1 mm is 100 microns
0.01 mm is 10 microns
0.010 ...
0.005 mm is 5 microns
So, I don't know for sure how hes measuring exactly ,
but its mentioned somewhere on the site he acquired digital calipers ,
and the numbers sound reasonable,
I think all he is doing is reading from his digital caliper display which shows 4 decimal spaces
or hes converting decimal mm reading into inches
or he is measuring a stack of papers
This is common advertising copy for $30 and under digital calipers
Measuring range: 0~6"/0~150mm
Resolution: ± 0.01mm/0.0005"
Accuracy: ± 0.02mm/0.001"(<100mm), ± 0.03mm/0.001"(>100-200mm)
Repeatability: ± 0.01mm/0.0005"
For comparison the numbers do sound reasonable (as averages),
even if they're actually off plus minus 0.001inch ( 1/1000 inch or 25.4 micron)
cause paper is squishy
casepaper chart lists smallest caliper as 0.002inch or ~50 micron
now it doesn't say thats "phonebook" paper but ,
origamiusa paper-review-17-bible-paper Thickness: The measured weight is 50 gsm. The thickness measurement is 62 microns like ~0.0024inch or 2.4/1000
origamiusa paper-review-9-onion-skin-paper Thickness: The weight is 35gsm. The thickness is 46 microns, the thinnest paper we have tested so far. For comparison, Kraft is 48 to 53 microns, and Japanese Foil is 52 microns.
And isn't the internet wonderful
How thick is onion skin ? 63 microns or ~0.0025inch or 2.5/1000
How thick is the skin of an onion ? 63 µm (microns.) Ten strips of the outer skin (tunic) of an onion were piled up and folded double to give twenty thicknesses. This booklet was measured with a micrometer and discovered to be one point two six millimetres thick. The mean thickness of a single layer of onion skin in this experiment was therefore sixty-three microns.
? I think you just volunteered
Maybe you can measure paper you already have, ie phonebook/yellowpages / biblepaper / onionskin
anyone can get some numbers ,
just see how many papers it takes to get a stack 1cm thick
then the thickness = 10,000 microns / number of sheets
it can be more precise if you use a camera to take a picture with a cm/mm ruler for reference, then count pixels in gimpshop or other photo software
you did it too
0.1 mm is 100 microns
0.01 mm is 10 microns
0.010 ...
0.005 mm is 5 microns
So, I don't know for sure how hes measuring exactly ,
but its mentioned somewhere on the site he acquired digital calipers ,
and the numbers sound reasonable,
I think all he is doing is reading from his digital caliper display which shows 4 decimal spaces
or hes converting decimal mm reading into inches
or he is measuring a stack of papers
This is common advertising copy for $30 and under digital calipers
Measuring range: 0~6"/0~150mm
Resolution: ± 0.01mm/0.0005"
Accuracy: ± 0.02mm/0.001"(<100mm), ± 0.03mm/0.001"(>100-200mm)
Repeatability: ± 0.01mm/0.0005"
For comparison the numbers do sound reasonable (as averages),
even if they're actually off plus minus 0.001inch ( 1/1000 inch or 25.4 micron)
cause paper is squishy
casepaper chart lists smallest caliper as 0.002inch or ~50 micron
now it doesn't say thats "phonebook" paper but ,
origamiusa paper-review-17-bible-paper Thickness: The measured weight is 50 gsm. The thickness measurement is 62 microns like ~0.0024inch or 2.4/1000
origamiusa paper-review-9-onion-skin-paper Thickness: The weight is 35gsm. The thickness is 46 microns, the thinnest paper we have tested so far. For comparison, Kraft is 48 to 53 microns, and Japanese Foil is 52 microns.
And isn't the internet wonderful
How thick is onion skin ? 63 microns or ~0.0025inch or 2.5/1000
How thick is the skin of an onion ? 63 µm (microns.) Ten strips of the outer skin (tunic) of an onion were piled up and folded double to give twenty thicknesses. This booklet was measured with a micrometer and discovered to be one point two six millimetres thick. The mean thickness of a single layer of onion skin in this experiment was therefore sixty-three microns.
? I think you just volunteered
Maybe you can measure paper you already have, ie phonebook/yellowpages / biblepaper / onionskin
anyone can get some numbers ,
just see how many papers it takes to get a stack 1cm thick
then the thickness = 10,000 microns / number of sheets
it can be more precise if you use a camera to take a picture with a cm/mm ruler for reference, then count pixels in gimpshop or other photo software
- Joined
- Jan 1, 2018
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That sharpness chart got me excited about putting as fine an edge on my blades as possible. I thought after getting my Ontario Rat1 to shave that i had hit the peak, now I know better.
It's pushing me. I feel an acute need for a 12k grit DMT plate.
Question: Has anyone ever used an electron scope to measure the edge radius of off a black (surgical black Arkansas?) I read that it can go down to 4 to 8 microns, but has anyone confirmed that? Anyone have better results in practice? The Translucent stones? I ask BC the SB arkansas is the finest stone i have.
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The finest black Arkansas stone grain is under 5 micron, somewhere in the vicinity of 3-4.
How sharp an edge you can get off this or that grit is a natural question, but there is no linear relation - see this thread:
https://bladeforums.com/threads/apex-width.1535064/
How sharp an edge you can get off this or that grit is a natural question, but there is no linear relation - see this thread:
https://bladeforums.com/threads/apex-width.1535064/
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- Jul 13, 2013
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- 48
Thank you wootzblade for sharing your experiences and knowledge on the art of sharp! Between your numbers and the information from the other websites mentioned I definitely think I know more about what's required to make my knives sharper, the only downside is I think I'll be needing more bandaids
I'm over in Perth so I might have to send a knife over that I have two of so I can see the difference between professional sharpening vs my efforts...
I'm over in Perth so I might have to send a knife over that I have two of so I can see the difference between professional sharpening vs my efforts...
- Joined
- Feb 24, 2014
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- 240
No worries, mate.
We've added a video to YouTube showing our sharpening and BESS testing:
Where it seems inappropriate to older generation, it is meant to be entertaining...
As to the quality - shot and edited by my 11-year son on his iPad.
We've added a video to YouTube showing our sharpening and BESS testing:
Where it seems inappropriate to older generation, it is meant to be entertaining...
As to the quality - shot and edited by my 11-year son on his iPad.
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- Dec 27, 2004
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I must admit it is very interesting and helpful. And I was trying to find more opinions about BESS device, however there's not much... Just a few on Amazon and a few on some forums. Why is that? Perhaps many people prefer to check sharpness in "old" ways? I just wonder...
And is it possible to order with shipment to Europe, or shipment is only to Australia/New Z. and USA?
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C
cutler81
For two reasons: first, BESS is young, the BESS edge sharpness tester was first patented in 2014, and became available in the end of 2015;
second - its primary consumers are industrial, they don't post on forums - there are publications on BESS in specialist magazines, but those are distributed by subscription.
The factory ships it everywhere, please check the manufacturer's website for contacts - I can't go into details here as this is not a sales thread.
For two reasons: first, BESS is young, the BESS edge sharpness tester was first patented in 2014, and became available in the end of 2015;
second - its primary consumers are industrial, they don't post on forums - there are publications on BESS in specialist magazines, but those are distributed by subscription.
The factory ships it everywhere, please check the manufacturer's website for contacts - I can't go into details here as this is not a sales thread.
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That is exactly what I thought... All I was wondering is if some knife makers use it or not to check the sharpness.
BTW, I'm also a bit interested in wootz
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With the most demanding tests, the edge oxidation effects the result. Immediately before those tests the edge should be stropped on clean smooth leather or clean linen to restore its original sharpness.
Chromium in stainless steel reacts with the oxygen in the air to form a passive complex chrome-oxide surface layer that prevents further oxygen from rusting the surface.
This film thickness originally is 3-5 nm, but can reach 20 nm on mechanically polished surface, i.e. worsen sharpness score by 5 to 20 BESS.
5 to 20 nm added to the apex radius, multiply by 2 in terms of thickness, i.e. 0.01 to 0.04 micron of added edge apex thickness.
Practically it means that the most challenging sharpness tests like the top HHT, that you can perform immediately after sharpening you can not an hour later. Oxidation can easily change your sharper than razor edge to just safety razor sharp if not duller, which is not enough for the most challenging tests.
Finally I've got a full assortment of Rizla cigarette rolling papers.
From the Rizla website: "The variation of thicknesses determines how long the paper burns for, Red papers are the thickest so burn the fastest while Silver are thinner and burn the slowest."
Smokers know that pleasure from a cigarette partly depends on how fast it burns.
I've got Rizla Silver - the thinnest, then goes Blue, Green, Orange, and Red is thickest.
Tested them for cross push-cut with the same blades I used to test Tally-Ho rolling paper:
Wilkinson Sword DE safety razor - scores 30 BESS on the PT50 edge sharpness tester, has 0.05-0.06 micron edge apex width; and
a knife that scores 20-25 BESS, i.e. about 0.04 micron edge apex width.
With the Tally-Ho rolling paper, the Wilkinson Sword razor almost passes the test, but the cut is somewhat rough; the knife passes cleanly.
Silver - Wilkinson Sword razor - clean push-cut
Blue - Wilkinson Sword razor - clean push-cut
Green - Wilkinson Sword razor - clean push-cut
Orange - Wilkinson Sword razor - roughens the paper
Red - Wilkinson Sword razor - tears the paper
Silver - Knife - clean push-cut
Blue - Knife - clean push-cut
Green - Knife - clean push-cut
Orange - Knife - clean push-cut
Red - Knife - roughens the paper
The most resemblance with the Tally-Ho rolling paper has Rizla Green.
Results contradict our intuitive expectation that a thinner paper would be harder to cut.
I've updated the chart on our website
http://knifegrinders.com.au/Manuals/Sharpness_Chart.pdf
So, I was going to get some rolling papers, to make some comparison tests with your chart... and was looking at this thread and then the rizla website... rizla.com ... and according to their page, the green and red are the same thickness... the only difference is the green has "cut corners". Both have same weight 17.5g, and are described as "medium thickness".
So, now I'm wondering... why you saw such a difference in performance?
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As you know, I have push-cut all Rizla varieties, Red and Green are clearly different.
They require different edge keenness and BESS score to cleanly push-cut them.
You can get yourself both the Green and Red, slice them, appreciate the difference and stop wondering WHY, rather take as a given.
For the purpose of this Chart we picked the Rizla Green as an international brand most closely matching our Australian Tally-Ho rolling paper.
BUT, push-cutting through Rizla papers can tell more about the edge, and their Micron ultrathin is especially interesting - the Rizla rolling papers can be matched to razor thickness/quality all along the range from the best to the worse - just it is out of the scope of this chart and study.
They require different edge keenness and BESS score to cleanly push-cut them.
You can get yourself both the Green and Red, slice them, appreciate the difference and stop wondering WHY, rather take as a given.
For the purpose of this Chart we picked the Rizla Green as an international brand most closely matching our Australian Tally-Ho rolling paper.
BUT, push-cutting through Rizla papers can tell more about the edge, and their Micron ultrathin is especially interesting - the Rizla rolling papers can be matched to razor thickness/quality all along the range from the best to the worse - just it is out of the scope of this chart and study.
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