Detailed question about DE blades

[jayhall]

Hi B&B Gentlemen - In real life I am an electrical engineer and anything new I come across, I tend to become interested in the math and physics concerned with it. Just started two weeks ago with my first DE shave and was blown away by how much better it was. Realizing that there are many different blade choices out there, can anyone point me to interesting articles or data on the blades themselves. For example, right now I am using the Feather blades and would like to know how sharp the blade is in microns and how much slant there is, etc.....

Many shavers on this forum tend to rate blades such as the Feathers, Astra SP and Personna Med Prep as the sharpest, but is there any actual manufacturing data to back this up?

Thanks - Jay

 

[the beav]

There's more to a close shave than just the sharpness of the blades (btw Polsilvers, Super Iridiums, and some 7 O'clocks blades should be near the top of the list).

You might want to look at these links:

http://wiki.badgerandblade.com/Double-Edged_Safety_Razors_Ranked_by_Aggressiveness

http://wiki.badgerandblade.com/Double-Edged_Safety_Razors_Ranked_by_Blade_Gap

 

[chilliman64]

I think jayhall is just asking about blade sharpness, not what blade gives the closest shave. popular opinion is that feathers are sharpest but they don't necessarily give the closest shave...

I can't answer if manufacturers release that sort of data, maybe someone else will know.

welcome to B&B + the gentlemanly art of wetshaving jayhall!

 

[jayhall]

Thanks Beav for that article on blade gap; interesting stuff. And thanks Chilliman, you are correct, I am not after the subjective closest shave type articles, I am after objective scientific specs on the blades themselves.

 

[chilliman64]

based on your profession I figured that was the case

 

[barazor]

Here is a link to another forum with Popular double edge blades under the scanning electron microscope (SEM) http://straightrazorplace.com/shavi...s-under-scanning-electron-microscope-sem.html

 

[DutchmanRiver]

wrong subforum. use the blade section!

 

[mblakele]

I would love to see more data from blade makers, but they seem to treat their sharpening specifications as trade secrets. The closest I have seen are marketing-oriented materials like this, which says that the Gillette Fusion blades have a tip radius around 250-Å, or 0.025 microns. I think it is safe to say that DE and SE blades are on the same order of magnitude. The diagram also outlines the coatings and adhesion layers.



Reading patents can be revealing too. But talking about sharpness is difficult because there is no measurement standard for sharpness. You can measure tip radius and grind angle, but there are no SI units nor ISO standards for sharpness. When blade makers write anything about sharpness, they talk about "force to cut" and use an FTC rig to measure the force required to cut some test material. But every blade maker seems to use their own rig and their own test material, so even if they published FTC numbers they would not be comparable.

Anyway the relevance of FTC tests to shaving is unclear, and sharpness is not everything. As shavers we only care about FTC for our own individual hair. Lowering FTC beyond a certain point is wasted effort. Instead we want other characteristics: smoothness, longevity, and price usually come into the discussion. A blade with a smaller tip radius might require a little less FTC, but it might also lose its edge more quickly. Many would cite Feathers as an example of this. Or a blade might have great longevity but might require a little more FTC, or might not glide as smoothly across the skin. Or it might be perfect otherwise, but too expensive.

Hair and shaving technique vary quite a bit, so one person might love a blade that is horrible for another. This might be because of FTC, or smoothness, or longevity, or sensitivity to a coating.

Oh, and http://wiki.badgerandblade.com/Science_Of_Shaving might interest you.

 

[awa54]

As others have already mentioned, the parameter of sharpness is hard to define and the attributes that contribute to the relative effectiveness of a razor blade are not readily quantified (or at least not without a major research grant!). There are different types of sharpness as well (the edge I would apply to a kitchen knife is much different from that I would put on a wood carving blade) and the sharpest blades (and by "sharpest" I mean the ones that subjectively feel sharpest on my face) are not always the ones that give the best shave either.

Maybe this is a research project for you?

 

[Fuzzy Chops]

Hi B&B Gentlemen - In real life I am an electrical engineer and anything new I come across, I tend to become interested in the math and physics concerned with it. Just started two weeks ago with my first DE shave and was blown away by how much better it was. Realizing that there are many different blade choices out there, can anyone point me to interesting articles or data on the blades themselves. For example, right now I am using the Feather blades and would like to know how sharp the blade is in microns and how much slant there is, etc.....

Many shavers on this forum tend to rate blades such as the Feathers, Astra SP and Personna Med Prep as the sharpest, but is there any actual manufacturing data to back this up?

Thanks - Jay

There are a few micrographs here:
http://www.flickr.com/photos/nanofab/sets/72157631830763986/
Even the dull ones look sharp...

 

[jayhall]

Thanks gentlemen, ...very informative. Definitely not something I want to study myself from a research point of view, but I can see how I would set it up in mind. A standardized array of pushed thru copper 'hairs' with all blades held at exactly the same angle and then measure coefficient of friction, FTC and rate of time to dull (dD/dt) until reaching a certain FTC.

Still reading and learning. Thanks.

 

[GarrettReid]

I'm majoring in accounting/finance so like jay I'm a numbers kind of person. It would be interesting to find some standardized way of determining sharpness.