Sharpness Chart

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maximus83 said:
Nope, I sure don't. As you don't demonstrate the applicability of the techniques described beyond the Tormek system, and don't include general guidance that isn't already available elsewhere, I found the book though interesting to be not especially useful to actual, practical sharpening in my case. It wasn't telling me anything new that I could actually use. I could see it being useful to folks who (1) have a tormek or plan to get one, and (2) folks who are not super active on places like BF and aware of other recent research like that of Larrin and Science of Sharp.
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Mate, do you realise that you deny our research originality in the thread where we define sharp edge by width in fractions of micron?
In 2016 people thought that a sharp knife has 1-micron edge - we showed that 1-micron is where the knife turns dull.
In appreciation of our research, Cliff Stamp changed slogan on his website from "Towards 1-micron" to "Towards 0.1 micron".

We developed a submicron scale of sharpness.
We did it on the shoulders of Scanning Electron Microscopy titans Dr. Verhoeven and Todd Simpson, by cross-analysis of SEM studies and sharpness tests done by us, Mike Brubacher, Chase Anderson and CATRA.

My Knife Deburring book is full of insights into the edge that you cannot read about anywhere else
Book Testimonials >>

It is sad that at some point in time Todd Simpson was nearly trolled out of this forum. I believe that Todd knows about the edge more than any human being on this planet, and if not the lack of appreciation, he would tell more us mortal. Even small things that Todd mentions in passing start me thinking. A mere thought that I could have helped bring more attention to Todd's studies and his website through this Sharpness Chart and my book makes me happy.
 
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And yet, you don't answer the main point. It's not that anything is wrong with your book per se, I was simply saying it has limited scope and applicability. Most folks don't have a Tormek, and that's how you demonstrate most of your sharpening insights and research. Most folks here have and use other approaches to sharpening than Tormek systems--that's neither good nor bad, it's just reality. You also seem to miss the point that research like Larrin's and Todd's, were available long before your book and many of us here are well aware of those useful sites. The principles that can be derived from their research have been frequently discussed here, in many threads. My point was not your book isn't useful, it's that it has applicability to a more narrow audience. As many of us here don't use Tormek and are aware of Larrin's and Todd's research, I stand behind my comment that the book isn't likely to present a lot of information that is new or directly practical for sharpening to folks who are outside your audience. No offense mate, it's just an informal a book review comment.
 
wootzblade said:
Mate, do you realise that you deny our research originality in the thread where we define sharp edge by width in fractions of micron?
In 2016 people thought that a sharp knife has 1-micron edge - we showed that 1-micron is where the knife turns dull.
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Pretty sure I have posts a good bit older than '16 where I asserted any edge that was functionally sharp was sub-micron.
The scientific understanding of sharp edges is nothing new, my father in law made a career of it at Kodak working on motion picture film. "You can learn a lot from a 1000x optical microscope but is just scratching the surface."

He was studying edges under electron microscope in the 60's, as well as via imprint and stylus.

Not to minimize your contributions, just setting the record straight. At the upper levels of industrial cutting, all of the revelations even by comparative heavy hitters are not really novel by any stretch of the imagination, only made more accessible. This includes methods of deburring, methods of grinding that do not create a burr, finishing with various slurries, films, strops, wheels of every composition you can imagine.
 
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Somewhere, my late grandfather, (gone since 1962), who was a master machinist at the Brooklyn Navy Yard, is smiling.

(The man was an inventor as well as an artist with his tools...and knew a thing or two about sharp.)

He was also, parenthetically, the one that introduced me into the world of pocketknives at about age 7.
 
Using the sharpness chart. Can anyone tell me what changes I have to make to get an edge from shaving sharp. (Against the grain) To hair popping or tree topping sharp?
 
Whoever has removed the Sharpness Chart from the stickies at the top, has destined it to getting buried under newer posts, i.e. to obliviscence.

Because of someone's inflated ego, the forum has been deprived of this information. The person who removed it from the stickies doesn't bother that the Sharpness Chart has had 70,000 views and has been a valuable reference for many people for several years.

Because of that, this is my last post on this forum.

When I started looking into the subject in 2016, the "razor" edge was thought to be 0.3 micron, and a sharp knife was thought to have 1-micron apex.
We showed that 0.3 micron is the knife "working edge", while the true razor is <= 0.1 micron. 1-micron edge is where the knife turns dull.
As I said, we did that by cross-analysis of SEM studies by Todd Simpson and sharpness tests done by us, Mike Brubacher, Chase Anderson and CATRA.
 
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If you take a stack of microtome blades and look at them edge on using old fashioned oil immersion microscope at 1000x they are invisible. Edges are under the approx .16μ that can be resolved.

Once you correct for distortion, you can get a far more accurate measurement using SEM, and some high resolution stylus probes are more accurate than optical microscope as well.

All that said, different edge mechanical differences provide significant advantages/disadvantages depending on what you're cutting. The answer to "how sharp" is another question: "what am I cutting?"
 
I’m trying to practice putting a hair whittling edge on my straight razors. However to practice on something less delicate, I’m sharpening my delica 4 and trying to see how I can make it hair splitting/whittling sharp I can get it.

Is it merely a matter of alternating strokes on your finest abrasive or is it something that I’m overlooking? All that being said sharpening has been really therapeutic for me the same way welding has, where it requires dedication to learn and your full concentration. ( Treatment for ADHD for $400 Alex) :D
 
Immersion oil is for use with lenses specifically designed for use with oil, and in my experience only in transmitted light imaging (eg biological samples under a coverslip). Leica, for example, doesn't make a 100x lens for incident light bright field imaging for use with oil https://www.leica-microsystems.com/objectivefinder/
Personally, I've only ever used immersion oil in the confocal microscope.
The problem with imaging a blade edge is not resolution, it's contrast - shiny metal objects are a PITA to image optically, and the reason that delineation etches are used in metallography.

Sub-micron resolution stylus probes absolutely cannot be used to measure a blade edge, that's just silly. These tips are so fragile, they break if you look at them the wrong way - they can only be used on flat surfaces.

It is quite difficult to measure the apex width/radius even with the best Field Emission SEM. It has nothing to do with "correcting for distortion" Just look at Verhoeven's unpublished manuscript, all the measurements are incorrect. Also, as far as I can tell, Edge on Up has not shown the results of their SEM study.
 
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Contrast was the biggest PITA for me. My twin boom AmScope does good but I don't want to keep unclamping and clamping my blades. I just got in a little USB microscope yesterday that seems to do pretty good. I got the drivers downloaded and played with it a little bit last night.
 
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ToddS said:
Immersion oil is for use with lenses specifically designed for use with oil, and in my experience only in transmitted light imaging (eg biological samples under a coverslip). Leica, for example, doesn't make a 100x lens for incident light bright field imaging for use with oil https://www.leica-microsystems.com/objectivefinder/
Personally, I've only ever used immersion oil in the confocal microscope.
The problem with imaging a blade edge is not resolution, it's contrast - shiny metal objects are a PITA to image optically, and the reason that delineation etches are used in metallography.

Sub-micron resolution stylus probes absolutely cannot be used to measure a blade edge, that's just silly. These tips are so fragile, they break if you look at them the wrong way - they can only be used on flat surfaces.

It is quite difficult to measure the apex width/radius even with the best Field Emission SEM. It has nothing to do with "correcting for distortion" Just look at Verhoeven's unpublished manuscript, all the measurements are incorrect. Also, as far as I can tell, Edge on Up has not shown the results of their SEM study.
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Thanks. I know nothing of immersion oil lenses, but have never had a lot of trust in BESS testing and turned down an opportunity to get a heavily discounted one. Too many concerns have been stated about what is being measured, how it is measured, and the repeatability of the tests. Seems SEM is really the best (only?) reliable way to get an accurate apex width. Which is why I suspect a fair number of our advanced sharpeners here seem to be skeptical of BESS testing and rely on other methods.

Unfortunately for a lot of us, SEM is not readily accessible. So we're left with using our homemade sharpening tests for example "Cuts X feet of cardboard until it can no longer whittle a human hair." I would love to have an objective measurement, but ultimately that's what I rely on too.
 
maximus83 said:
Thanks. I know nothing of immersion oil lenses, but have never had a lot of trust in BESS testing and turned down an opportunity to get a heavily discounted one. Too many concerns have been stated about what is being measured, how it is measured, and the repeatability of the tests. Seems SEM is really the best (only?) reliable way to get an accurate apex width. Which is why I suspect a fair number of our advanced sharpeners here seem to be skeptical of BESS testing and rely on other methods.

Unfortunately for a lot of us, SEM is not readily accessible. So we're left with using our homemade sharpening tests for example "Cuts X feet of cardboard until it can no longer whittle a human hair." I would love to have an objective measurement, but ultimately that's what I rely on too.
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Repeatability just takes time. Plus my nerves aren't as good as they used to be. It would be easy to skew the results though. But it gives me a reasonable assessment to how much an edge dulls after cutting a few strips of 2" HD Poly or Nylon straps. Cardboard would be cheaper to use than my straps. It just gives me something fun to do.
 
^+1 hate to see wootz move on just over this discussion. Dude it's meant to be just a discussion and informal book review, nobody that I've seen is knocking your book, saying it's bad, nor your contributions. Suit yourself, but hope you don't split just over this discussion. You'd added a lot, I've enjoyed a ton of your previous posts and convos about the sharpening chart, some of your Tormek discussions even though I don't own one, etc. For the record, I too would still like to see that chart as a sticky, not clear why removed but not my call.
 
I have found wootzblade's posts on this forum to be very enlightening.

I have purchased and read his book, and I have found his approach to burr removal to be very helpful.

I hope he reconsiders.
 
I was able to use oil immersion w/metallographic microscope for 1000x images, even able to angle the edge. Images at 400x not good enough to make out apex features but using depth of field one could estimate degree of bevel convexity and scratch depth. Plus the software allows for a range of various contrast enhancements.

And for a fact, stylus profilometers were used for sheer cutters and some forms of burst cut dies. You can't use them with most thin blades, but as the angle becomes less acute yes.

Spatial distortion is definitely an issue w/SEMs, better for studying morphology than assigning absolute measurement values, although methods of compensating are now pretty effective.
 
maximus83 said:
Thanks. I know nothing of immersion oil lenses, but have never had a lot of trust in BESS testing and turned down an opportunity to get a heavily discounted one. Too many concerns have been stated about what is being measured, how it is measured, and the repeatability of the tests. Seems SEM is really the best (only?) reliable way to get an accurate apex width. Which is why I suspect a fair number of our advanced sharpeners here seem to be skeptical of BESS testing and rely on other methods.

Unfortunately for a lot of us, SEM is not readily accessible. So we're left with using our homemade sharpening tests for example "Cuts X feet of cardboard until it can no longer whittle a human hair." I would love to have an objective measurement, but ultimately that's what I rely on too.
Click to expand...

I need to make a new clamp for my old Edge Inquisitor. Using 3/8" manila it was able to show repeatable indications of dulling based on static load needed to complete a draw or pressure cut. Differences of half a pound on an edge that could still pass all manner of cut tests, shave hair etc.
BESS biggest advantage is standard media, where rope is comparative. This can be helped by using multiple coils per test.

If wootzblade wants a high level of access, a higher level of membership would be helpful.
 
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