Worlds sharpest blade???

C

ChrisLee

Joined
May 26, 2013
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199
Every now and then I do a search for what is the worlds sharpest blade and as expected the internet turns up a bunch of useless links. Has anyone else here come across or can point me in the right direction to find the answer to my questions?
 
It won't be a steel blade for sure.

And if steel, there's probably only a handful of people on this forum that could answer that, and it would require lots of magnification.
The guys at maintenence and tinkering would be useful.
 
Is your question "what steel can be ground to the thinnest edge without disintegrating" or is your question related to some practical use? Many steels can be made unusably sharp, but I don't know why that would be relevant.
 
austexjg said:
Obsidian fractures to 1 atom at the edge - does that count?
Click to expand...

You do realize that each type of atom has a different size. Not only that, the relative size of atoms can be studied, but the size of an isolated atom can't be measured because we can't determine the location of the electrons that surround the nucleus.

That being said, there are three ways to acquire an "educated guess" as to the size of an atom, metallic radii; covalent radii, and ionic radii. Each one of them will result in a measurement that is read in "nm" or nanometers, or more accurately an Angstrom. An Angstrom equates to .1 nm.
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To the OP: An edge that is made of obsidian can approach 3 nm.
With new technologies being taken into account, there are polished diamond edges that can also approach an estimated 3 nm.
Information on diamond edges was found here:
https://www.ncbi.nlm.nih.gov/pubmed/12695964
 
^well said!

I spent hours stropping my sebenza so it could whittle my hair. It dulled/rolled so easily though. It's nice though when it lasts.
 
whereas a knapped piece of natural glass is a strong contender, the sharpest sharpened blade is a diamond, used for eye surgery.

nitpick: glass/obsidian is a molecule SiO2, so you can't have only atoms at the edge.
 
hank_rearden said:
whereas a knapped piece of natural glass is a strong contender, the sharpest sharpened blade is a diamond, used for eye surgery.
Click to expand...

The act of flaking off shards via the knapping of flint, chert, obsidian or the like is the act of creating a sharpened edge on a previous dull surface. That act is known as sharpening, be it through material removal (Knapping, grinding or polishing), or the movement of material due to the hammering of bar stock to a crude edge when heated via a forge.

Sharpening is sharpening, though one may be more finely tuned than the other in regards to a measurable degree and the cleanliness of the apex, both may cut given enough force.

On top of that, they both have been measured at an estimated 3 nm. The perceived differences between the two should be so miniscule that I would be willing to bet that the most modern of robotic surgeons aids wouldn't be able to get an accurate read on the pressure differential exerted between the two blade materials on the utensils.
The only difference that Might be encountered would be in wear due to the differences in the Mohs hardness and stability of the diamond vs fragility of glass and an encounter with a material harder than flesh.
 
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HwangJino said:
^well said!

I spent hours stropping my sebenza so it could whittle my hair. It dulled/rolled so easily though. It's nice though when it lasts.
Click to expand...

That's why one should carry two blades. One for whittling unsuspecting hair, the other for work.
 
Many steels can be sharpened so sharp you won't be able to tell the difference without a powerful microscope.

..but in my experience, the sharpest edge is the weakest edge.

Why are you asking?
 
Now get practical: of all the knives and scalpel blades I have used , the sharpest blade tip I ever met is by far the one of the Spyderco Nilakka. For any practical use it is no good. I have convexed the edge of my first Nilakka, and now I am waiting for my new Nilakka to arrive, this one will remain untouched in the box 'till I am old. Very old.
 
Ferahgo said:
That's why one should carry two blades. One for whittling unsuspecting hair, the other for work.
Click to expand...

:D :D Yes - let's keep those unsuspecting hairs under control. A life well lived can only be lived carrying two blades otherwise the hairs will overwhelm us. :D

You made me laugh Ferahgo!
 
NJBillK said:
You do realize that each type of atom has a different size. Not only that, the relative size of atoms can be studied, but the size of an isolated atom can't be measured because we can't determine the location of the electrons that surround the nucleus.

That being said, there are three ways to acquire an "educated guess" as to the size of an atom, metallic radii; covalent radii, and ionic radii. Each one of them will result in a measurement that is read in "nm" or nanometers, or more accurately an Angstrom. An Angstrom equates to .1 nm.
------------
To the OP: An edge that is made of obsidian can approach 3 nm.
With new technologies being taken into account, there are polished diamond edges that can also approach an estimated 3 nm.
Information on diamond edges was found here:
https://www.ncbi.nlm.nih.gov/pubmed/12695964
Click to expand...

I know this is the dorkiest topic ever, and an older thread...knives + science = my wife rolling her eyes, But: I stumbled upon this cool thread by doing what a lot of us here on BF do, searching for topics of interest, this time was thinnest edge. And while I was wanting to know the thinnest "steel" edge so I can try out knives made with that steel, I've always found the Obsidian thing so interesting...but until now I never actually did the research (Google research, the best kind). I knew that Obsidian was a preferred surgical scalpel material & that it was capable of getting sharper/thinner at the edge than any steel....but I had NO IDEA!! About 3nm?! Wow. But as this guy here points out, Obsidian can get to, in the absolute best case scenario, down to the width of about one "Molecule", not one "Atom". And he also correctly points out that both of these terms can't accurately be used generically (different examples of both can vary by 3 times or more). With that said, an average atom is about 10-times smaller than an average molecule....SO = an Obsidian knife can possibly get down to one molecule thick at the edge, but never ever one atom at the edge....but hey, 10 atoms at the edge is more than enough to blow my freaking mind....I'm actually shocked by this! I do have one Obsidian knife made by a local Native American (I live in the foothills of No. CA)...and now I'm going to throw that puppy in a sheath and do some light slicing with it instead of leaving it up on the mantel all the time - Obsidian has my respect! But I still want to know which commonly used steel can produce the keenest usable edge consistently....is it 52100??....I'll keep looking at other threads....love Bladeforums!
 
Too sharp equalls rolling.. I recently sharpened a kitchen knife for my girlfriend - would have been perfect for slicing, but she used it to chop up parsley. She says, "I thought you just sharpened this??". I checked it out and it was soooo rolled! So I gave a (roughly) 15 degree per side edge and it was fine. Anyway - SUPER sharp is kind of pointless as it will either roll or simply dull to quickly..
(I know next to nothing next to 95% of the people here, but that's my 2 cents...)
 
I can't speak for the world, but the sharpest knife I have is a piece of Hitachi White Steel forged by Murray Carter.
 
For an extremely sharp steel edge that lasts awhile I'd recommend a fine grained stainless like AEB-L, or one of its cognates by Sandvik. Coincidentally, these are used to make modern face razor blades. An extremely fine edge is very susceptible to corrosion on non-stainless steels, and even the slightest dampness can wreck the very apex. 52100 or O-1 will do a good job if corrosion isn't a factor.
 
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