Science of sharp: Cool SEM microscopy of a blade

[grepper]

Some of the best SEM microscopy of a blade I've seen.  Pretty much tells the story of what's going on.  All it takes is 5K X – 10K X magnification.  If you guys send me enough donations, I'll buy one and be more than happy to post pics. 

Part 3 is quite entertaining and shows how sensitive human skin is. "Shaving with a razor with such a foil edge burr generally results in extreme levels of skin irritation."

Edge-leading and edge-trailing honing:
https://scienceofsharp.wordpress.com/2015/02/09/the-pasted-strop-part-1/

What is a burr?:
https://scienceofsharp.wordpress.com/2015/01/13/what-is-a-burr-part-2/

Role of the strop material:
https://scienceofsharp.wordpress.com/2015/03/31/the-pasted-strop-part-3/

[grepper]

Replying to my own post. 

Read carefully through Part 3, Role of strop material.   It is quite informative.  Especially the conclusions at the end, and how much stropping is required.  I found all three parts most informative.  Worth the read and consideration.

A lot of the images that I have posted here are of burrs.  Why?  Because I am not satisfied with any method that I have come up with yet to remove burrs.  Many times, even after honing or stropping, (herein after called stropping), and then examining the edge under a microscope, some fragments of burr remains.  Sometimes additional stropping seems to dull the edge. 

Sometimes I have noticed that a few edge-trailing swipes on my jeans back and forth over my thigh seem to improve the edge.  Really?  Denim?  How could that be?  Nonetheless it really seems to work.  Why?

Well, maybe it's removing micro-burrs left over.  Maybe it's removing micro-oxidation.  Maybe it's straightening a micro-roll of the edge.  I have yet to verify any of this and I'm not sure if I can with my cheesy little USB scope.  And..., it is very time consuming to do so.

I get the idea from this guy's work that it really is possible to dull an edge by over stropping.  But it is also evident that wire edges, burrs, rolls, foil edges and the like must be removed or the edge will lose its keenness quickly or never be as sharp as it could be.

Too much to learn.  Too much experimenting required to really figure it out.

I guess sharpening is as simple or as complicated as you want to make it.  I can easily get blades plenty sharp enough for all intents and purposes, and tomatoes.  If they get dull, it's easy to whip them back into shape.  Maybe that's good enough. 

I can't even imagine trying to figure out how sharp is too sharp for something like a kitchen knife.  What level of sharpness for different steel hardness provides the most enduring edge?  A razor edge might be cool for a few cuts and then start to roll.  But what about really hard steel compared to softer steel? Etc., etc., etc.

It's a hair pulling, time consuming freak show!

[Herman Trivilino]

Mark, I think you already know that a too-sharp kitchen knife will perform superbly at first, but then quickly get dull as soon as it's actually used in the kitchen for anything other than showmanship.

I spent about an hour today sharpening every knife in my kitchen. I wasn't concerned with anything other than what happened afterwards. I easily pared the tips off the green beans, effortlessly cut through bread, and sliced up a grilled pork tenderloin. Then I sat down to enjoy a meal that I had prepared for me and my wife.

[grepper]

Herman - 

A fine evening indeed.

[Jan]

Very interesting reading, Mark, thanks for posting the links. 

There is now a new and also very interesting article on the scienceofsharp web: Optical vs Electron Microscope https://scienceofsharp.wordpress.com/2016/11/03/optical-vs-electron-microscope/

I have to say that your images are better than the one over-exposed image captured by USB scope posted there as an example. 

What concerns the electron microscopy, in the town where I live (Brno) they are two top manufactures of SEM. The larger one, FEI Czech Republic, produces circa 600 microscopes per year, where an average price is 1 million $. 

Jan

[grepper]

And thank you Jan for posting that link.  Another interesting read.

The USB microscope used in that articles is a Dino-Lite AD7013MTL.  I looked at Dino-Lite when I got mine and, IMHO, concluded them to be extremely overpriced.  The AD7013MTL is currently selling for $750.00 on Amazon.  Really?  $750.00???  Unless I'm missing something, I think purchasers of this are laboring under the delusion that with USB scopes price = quality = features.  The Celestron scope I use is currently $76.99 on Amazon:
http://tinyurl.com/zeset2z
http://www.celestron.com/browse-shop/microscopes/digital-microscopes/handheld-digital-microscope-pro


In the Amazon description: Note: Final magnification determined by monitor size)   (Chuckle )

The specs of the Dino-Lite are basically the same as mine: 5mp, ~200X optical and the same sluggish USB 2.0 interface.  I presume by the nature of the Science of Sharp articles that this guy obtained the best image he could from the Dino-Lite, and it's no better, if not worse than the crappy images produced by mine.  And why the tectonically sluggish USB 2.0 interface of yesteryear?  You might as well deliver data packets, bit by bit, in a Conestoga wagon.  I am sure that now days it's not the cost of USB 3.0 electronics keeping USB scopes at the evolutionary level of just emerging from the sea.

Nonetheless, for the price, USB scopes are fun and more or less useful.

Notice the huge improvement in image quality between the USB scope compared to the "professional quality optical microscope (Mitutoyo FS70)" @ $8,495.00 with a Zeiss Axiocam ICC5 camera @ $4,100.00.  I guess an extra $12,515.00 equipment cost over the cost of my scope has the edge in image quality.

Consider the current cost of digital cameras.  Even the inexpensive ones produce much higher quality images than the USB scopes do.  I'm not sure that low resolution 5mp digital cameras are even still available, but even 5mp cameras produce better imagery.  I don't know why USB scopes produce such crappy images.  I'm guessing lens quality, sensor quality and their internal image processing software are to blame.  It would be nice if USB scopes caught up with the price/performance of the current batch of digicams.

In the article, the author gleefully proclaims, "I compare only side-view images simply to demonstrate where optical microscopy falls short of electron microscopy in this application...".   Well... Isn't that nice.   

I can't disagree though.  It gets much more interesting with 5K X – 10K X magnification.

[Jan]

In the discussion to the article Optical vs Electron Microscope I have found interesting info: "Each of the SEM images requires approximately 3 minutes and the research rate is $55/hr."

It is quite reasonable price, I think. 

Jan

[Rob]

Just remind me how your tomato's will benefit again :-)

[Ken S]

Rob,

You apparently have not seen the Black Friday ad advertising a free bushel of tomatoes with every purchase of a Mitutoyo microscope and Zeiss camera.   ( I hate this auto word "correct feature that decided for me that I meant to type Zeus instead of Zeiss!)

Jan, I agree that the $55 per hour rate for electron microscope scans seems very reasonable.

I happen to have a thirty year old Nikon 105mm Micro Nikkor lens left over from my film days. It does a very ample job of shooting 1:1 (life size) with my digital camera. It is no rival for a microscope, however, it was paid for thirty years ago.

I find this discussion of micro photography interesting, however, my low tech method of feeling for a burr and then polishing seems to work adequately.

Ken

[Jan]

Rob and Ken, you're correct, for majority of sharpener's inspection purposes a watchmaker loupe is all what we need for edge observation. 

In the shop I use an old imagining lens from objective of a 35 mm movie projector.

The microscope is good e.g. for comparing surfaces polished by different techniques or compounds. I use it also for inspection of the factory grinds of new knives. 

Jan

[Ken S]

Jan,

The more I think about the cost of making electron microscope images, the more convinced I am that that price is indeed a real bargain! The late Leonard Lee's fine Sharpening book has a chapter with many electron microscope images. I am intentionally repeating myself when I state that this book should be part of every serious sharpener's home library.

Ken