Popular double edge blades under the scanning electron microscope (SEM)

Today I am going to treat you to something real nice. Due to my current employment status I have access to a scanning electron microscope.The SEM is capable of extremely high magnifications up to (theoretically) 1.000.000times. Naturally the SEM I am using is not so much state of the art but still capable of tremendous magnifications.So far I have been able to produce images up to 5.000x magnification (Verhoeven^[1] maxed out at 3.000x). The magnification of the image is listed under SEM MAG:Up to today I have taken sample images of different popular double edge blades.The first set of pictures is a fresh Feather stainless steel blade.The blade has not been cleaned and came fresh out of the box. The blade has been gold coated via sputtering^[2]


Please click on the pictures for full image size


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It is clearly visible that the blade is pretty dirty.
I made a second set of images, cleaning the blade prior to sputtering.
The Feather has been exposed to xylene steam, a highly effective organic solvent.This is what the Feather looked like this time


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The next set of pictures shows a fresh Personna (red) blade. The blade has been untreated, uncleaned and sputtered.

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[1] Experiments on Knife Sharpening. John D. Verhoeven, 2004
http://www.bushcraftuk.com/downloads...nifeshexps.pdf

[2] Sputtering produces coatings of gold only slightly bigger than a couple of gold atoms.
The gold makes the surface more contuctable and improves the resolution of the image.

Here are some samples of a Derby blade.
The picture on the left shows the derby sputtered and untreated.
The picture on the right shows the opposite side of the blade but this time it has been corked five times with no pressure
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Now for some experimenting.
On the left side of the image you see a very well used Feather stainless blade.
On the right side you see the opposite side of the blade treated with 0.5µm diamond on felt.
The blade has not been sputtered but cleaned

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I hope you enjoy these pictures.
Remember these are merely pictures and can be misread.Please to not distribute or use these pictures without my permission

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Here is an example for the manufacturing process of a Derby blade.
The blade shows at least three different angles with a coarse primary bevel, a secondary bevel and a completely polished tertiary bevel

Thanks for the pics, I had no idea what my Feathers looked like under the scope.

How thick is the sputtered gold, I typically do 5nm and that is not visible on the sample with those magnifications, you will be seeing it when you get in the x30K range or higher
Images look great.

wow, thats crazy. those feather blades look terrible compared to the derby's...the derby's seem to have a much neater and cleaner blade :) thanks for the awesome experiment

Like with straight razors a great LOOKING blade doesn't always translate to a great Performing blade.

Great pictures, thanks.

Thank you for taking and sharing the pictures. Edges get a bit intimidating at that resolution.

would love to see a side by side of 6-8 different blades all new at the same resolution across the columns and then after 1, 2, 3, 4... shaves down the rows

Thanks for the images. Reminds me of my uncle when i was a kid though. He worked in a sausage factory and told me the old cliché was true ..... if you see how it is made you wouldn't want to eat it..... Sort of my reaction to the feather images ..... after the gillette swede that was my go to blade when I shave DE.:D

I got some great news.
After several days of experimenting I finally came up with a way to improve the image quality.

I tilted the blade heavily towards the "camera". It isn't a full 90° edge on view, but kind of a ~70° angle.
This way the SEM gets much more electrons from the edge itself.
For comparison sake here are two sets of pictures from the same blade, a Souplex DE.
Klick for enlargement

Blade flat:

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Blade tilted towards SEM-Detector
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Magnifications to 7.000x and more can be realized this way.
Here, defects become visible

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Very nice. I wonder at what point it becomes irelevant as to imperfections in the edge? I enjoy your work, but even though I (we) strive for perfection, I know it is unachievable. I wish it was.

Great images. Thanks for sharing. But, wondering if there is anyway to translate these images into how well a blade will shave?

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Great images. Thanks for sharing. But, wondering if there is anyway to translate these images into how well a blade will shave?

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Hi Ziggy,

unfortunately there is no way to estimate the performance of a blade only by looking at it,
even under close magnification. The performance of a blade is a function of many variables,
such as geometry of the blade, type of the saftey razor, preparation and type of beard, type of grind and many others among them so called confounding variables like "bad day", or bad technique etc.

But there is still much to learn from these pictures anyway. High magnification just isn't the holy grail of sharpening :)

Could you do a shot with a hair up against the edge of the blade? That would be great to see up close.

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Could you do a shot with a hair up against the edge of the blade? That would be great to see up close.

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Unfortunately no, this is not possible. I get this request a lot but there are some simple reasons.
First of all human hair is made of a material that is not condictive like metal.
The surface to be investigated under an SEM needs to be conductive for the electrons to be reflected.
It is possible to make non conductive matrerials visible under the SEM I am using using a sputter coating technique.
Similar has been done here. Check chapter one
Google Books

Now you can understand the second reason. Even though it would be possible for me to sputter coat a human hair,
its sheer size would fill the whole image leaving nothing to see from the actual edge.
A human hair has a diameter of roughly 50µm. It actually is too big to be visible side by side with the edge, that gets interesting at around 1-10µm

New images have arrived. This time an Astra blade has been examined.
The first set of pictures shows the bevel with the blade tilted towards the detector.
The Blade lies not flat to ensure a better view on the edge.
The Blade has been cleaned with Xylene and korked five times.
Klick for enlargement


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This time the Astra blade has been cleaned with Xylene, not been korked and
the view is straight down the edge. You are looking directly on the very cutting edge.

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Here I added some comments for clarification


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Is that a spot of rust on the astra in the last pic?