Scanning Tunneling Microscope @MIT meets Razor Blades

[Avi]

I thought you guys would enjoy this:

Cutting-Edge Research Shows How Hair Dulls Razor Blades

Hair is soft compared with steel, but shaving can dull a razor surprisingly quickly. A new study examines exactly how a strand of hair can chip and crack a sharp blade.

www.npr.org

Perhaps one of the highlights here for those of you w/ wire-brush beards is this

"It found that, under the right conditions, a hair can actually produce tiny chips in the blade. That was unexpected, says Cemal Cem Tasan, a professor of metallurgy at MIT"

The actual article in Science is here:

Science | AAAS

science.sciencemag.org

I just realized the lead author is originally from Turkey!! We should get him analyze the Derby Extra

Regards
Avi

 

[thombrogan]

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[Bert0324]

Very interesting. Thanks for providing these links.

 

[thombrogan]

And apologies. I just went to the abstract. The main article has the goods

 

[BigJ]

Interesting article!! Thanks for bringing this to my attention!!

 

[AZ1976]

It's completely counter-intuitive that hair can do such damage to a substance that is 50x harder over such a short period of time. Fascinating stuff.

 

[dndrich]

I saw that report also, and very interesting. Based on that I will change my blades every 3 days. It appears there is just no way to avoid the damage to the blades.

 

[Mouser]

It's completely counter-intuitive that hair can do such damage to a substance that is 50x harder over such a short period of time. Fascinating stuff.

I seem to remember a commercial? or something on TV saying the the average whisker is 3? or 5? times tougher than a copper wire of the same thickness. If that's true then it's easier to see how.

 

[SillyPancake]

Good read. Thank you for posting the article.
Given the extremely low edge angle, it is not that surprising that there are micro chipping on edge, if it can happen on a knife edge, then why not on razor blade? Interesting article.

 

[Invicta]

I seem to remember a commercial? or something on TV saying the the average whisker is 3? or 5? times tougher than a copper wire of the same thickness. If that's true then it's easier to see how.

That is fiction!
Equivalent diameter of copper and hair will have equivalent tensile strength. Hair is much easier to cut than copper wire.

 

[Clay S]

Hair is 2-2.5 mohs, copper 2.5-3 mohs

 

[Mouser]

That is fiction!
Equivalent diameter of copper and hair will have equivalent tensile strength. Hair is much easier to cut than copper wire.

Ok then. Wasn't stating a belief but a memory.

 

[Mitzie]

Hair is 2-2.5 mohs, copper 2.5-3 mohs

Whiskers certainly get tougher with the older you get !

 

[Mouser]

After some quick googling I don't know what to think. I found several articles that say whiskers are as tough to cut as copper wire including a second hand Twitter post claiming to have known a member of the old Gillette's research team that supposedly studied it and concluded the same. But just as many ones denying it. I'm just going with whiskers are tougher than hair. But I can't say I have any evidence of that either.

 

[Invicta]

Hair is 2-2.5 mohs, copper 2.5-3 mohs

The Mohs scale measures hardness in minerals. Hair is not a mineral but biological matter so I cannot see the correlation.
What I have noticed is some people claim to have hair as tough as copper wire and others even claim to have stubble as tough as steel wire but neither seem to be supported by objective analysis.

 

[Mouser]

The Mohs scale measures hardness in minerals. Hair is not a mineral but biological matter so I cannot see the correlation.
What I have noticed is some people claim to have hair as tough as copper wire and others even claim to have stubble as tough as steel wire but neither seem to be supported by objective analysis.

Thank you, I appreciate knowing things like that.

 

[Clay S]

The Mohs scale measures hardness in minerals. Hair is not a mineral but biological matter so I cannot see the correlation.
What I have noticed is some people claim to have hair as tough as copper wire and others even claim to have stubble as tough as steel wire but neither seem to be supported by objective analysis.

Mohs hardness scale has been used to give hardness values to non-mineral matter, such as worked metals and keratin, though hardness would only be a component of cutting difficulty.

 

[TheBigL]

Whiskers certainly get tougher with the older you get !

I can definitely say I have a harder time getting a good shave since I've started to get grey/white hairs in my beard.

 

[psfred]

And this is why I shave at a shallow angle -- there is an "ideal" angle of the blade to the hair shaft that gives adequate back clearance while causing minimal "prying" force on the edge. That way most of the force required to cut the hair is directed into the bulk of the blade with minimal side force. Steep angle shaving applies more force sideways the the edge, hence is more likely to chip the edge.

Razor steel is very, very hard and therefor quite brittle. That's why coarse beards wear blades out faster than fine beards, and why beginners with undeveloped technique go through blades faster.

 

[BigJ]

Whiskers certainly get tougher with the older you get !

+1! But I am trying to get younger!!