Metallographic microscope images

[Swxteacher]

In my lab I have a Buehler ViewMet Inverted Metallographic microscope with a 3MP OptixCam camera attached. I wanted to see a couple of different blades BEFORE shaving. I plan on conduction hardness testing also and posting my results. I looked at the edge of both blades and found imperfections (holes, chips, and cracks). This is probably a common problem because the edge is so thin, but again the few the imperfections the less chance of blade failure.

The first two blades photographed were the Gillette 7 O'Clock Super Stainless (Green box) and the Wilkinson Sword (black box w/ white paper) blades.

I will post images with 50X, 100X and 200X. The 500X objective is useless for this type of comparison. It is mainly used for examining grain structure after the metal has been polished and etched.

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Gillette 7Oclock Super Stainless 100X

Gillette 7Oclock Super Stainless 200X


Wilkinson Sword 50X-A
(Note: the WS blade appears to have a primary bevel and a secondary bevel. I will follow up with a cross section view after a section and mount the blade)

Wilkinson Sword 100X

Wilkinson Sword 200X

 

[saliavin]

This is incredible! Consider me subscribed!

 

[Vercin]

interesting hope ull continue this thread with lots more blades

 

[VerbaVolant]

... I plan on conduction hardness testing also and posting my results...

I am also interested in these tests since I noticed a huge difference between blades when attempted to cut them with snips. What method are you thinking to use for measuring hardness?
Thanks for posting !

 

[Swxteacher]

I am also interested in these tests since I noticed a huge difference between blades when attempted to cut them with snips. What method are you thinking to use for measuring hardness?
Thanks for posting !

A Buehler (Mitutoyo) Rockwell Hardness test instrument. I am using the HR15N scale. This scale is one of the superficial scales that is used for hardness testing thin metals as opposed to testing thicker metal samples like chisels or plane blades.

Buehler ViewMet Inverted Metallographic Microscope w/ OptixCam camera


Buehler Hardness Tester

 

[jdub7758]

You have to do this with the world famous Feather blades!

 

[rajagra]

Could those imperfections be in the coatings?

 

[Swxteacher]

I took 5 different reading on each blade and got the average hardness value

Gillette 7 O'clock Super Stainless: HR15N = 85.28

Wilkinson Sword: HR15N = 85.5

Both of these numbers equate to a Rockwell Hardness "C" scale = 50.

This is very close to the hardness of a roll of 300 Series Stainless Steel Shim Stock

 

[Swxteacher]

I have some Feathers in my limited collection

 

[Swxteacher]

Could those imperfections be in the coatings?

If you look at the WS 200X I think we see the coating as iridescent looking. The larger pits are in the metal.

The 7 o'clock has a hole through the edge. I'm thinking after a few shaves this wold break off and cause a rough shave or some pulling and tugging.

Remember, this is just one section of the blade; an area less than the size of a pinhead. Both blades have minor inperfections along the entire edge and on both sides.

I will try to go back and put some measurements in the photos for reference.

 

[VerbaVolant]

I took 5 different reading on each blade and got the average hardness value

Gillette 7 O'clock Super Stainless: HR15N = 85.28

Wilkinson Sword: HR15N = 85.5

Both of these numbers equate to a Rockwell Hardness "C" scale = 50.

This is very close to the hardness of a roll of 300 Series Stainless Steel Shim Stock

Thank you!

Those values are awfully close, don't you think? Two different blades/manufacturers, Russian and German, and yet almost same hardness... Could they be from the same stock?
Do you have any Blue Bird blades? I tried cutting one to make a shim and found it extremely hard.

 

[Swxteacher]

I don't have any Blue Birds. I will continue to test with Feather, merkur, Personna, Kai (Personna and Kai are 2 of my favorites), Astra, and Polsilver SI (my favorite blade!).

I will have to do this during lunch and breaks, so it may take awhile.

 

[Swxteacher]

Statistically there is no difference on hardness

 

[joost]

Great images. Thanks for doing this.

 

[mblakele]

Great post. From your 200x images it looks like I need to check my math: they appear to be much more detailed than what I thought was 200x with my handheld scope.

Are you planning to look at any used blades?

 

[Swxteacher]

....Are you planning to look at any used blades?

Not at this time, maybe after I get a good data baseline.

 

[Wingnut]

I want this guy's toys!!!

Seriously, this is some really cool research! Thanks for sharing!!

 

[VerbaVolant]

Sorry, I didn't get this:

Statistically there is no difference on hardness

Maybe a lighter load for the thin blade?

 

[oldbluelight]

Sorry, I didn't get this:



Maybe a lighter load for the thin blade?

I think he's referring to the minute difference between the results. Such a minor variation would not be sufficient to conclude they are truely different. I think it's called a T test and was developed by a guy who worked for the Guiness brewery. Raise your glasses high for bubbly innovation in statistical theory.

 

[Swxteacher]

OK

Here is a screen shot of my first attempt at recording this data.



I plan on putting all of the images and this spreadsheet on a Google site that I can edit and post new images as they are taken

I prepared the first two section samples and have begun polishing them. These sections will show the end view of the blade under 100X and 200X power. It should show if there is any secondary bevel on the blade. I don't think that I will etch the sections (with acid) to see the grain structure as this isn't too important to this conversation.

You can see the images for all of the blades listed above so far at: https://sites.google.com/site/myderazorblades/