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Obsidian/Glass as a Cutting Edge

Posted by Ryan Nafe 
Obsidian/Glass as a Cutting Edge
December 06, 2015 03:32PM
I have an obsidian knife made by a traditional flint knapper out of South Dakota. The handle is made from the jawbone (complete with teeth) of a badger. I have heard through indirect sources that obsidian/glass fractures to the molecular level when it is chipped away, and that this is the reason why glass in general can be much sharper than steel, while obviously remaining more brittle. Is there a practical application for obsidian or glass as a cutting instrument? I have also heard indirectly that certain surgical applications make use of an obsidian/glass blade because it is so sharp and clean cutting that it greatly reduces healing time and scar tissue. Can anyone expand on this? Any information is greatly appreciated fellas
Re: Obsidian/Glass as a Cutting Edge
December 06, 2015 03:52PM
I know all surgical tools are metal or plastic, never seen anyone that makes a non steel blade. Also, glass is way to dangerous given steel technology. One sliver breaks off inside you.....argh.
Re: Obsidian/Glass as a Cutting Edge
December 06, 2015 04:00PM
Obsidian scalpel links/references
Ancient Technology in Contemporary Surgery

which says Don Crabtree knapped those specimens, and apparently hes famous guy smiling smiley


The two parallel cutting edges are extremely sharp, the edges themselves measuring approximately 30 angstroms in thickness. The comparison between this edge and that of a new razor blade is shown in Figure 3. At a magnification of 10,000 times, the razor blade edge appears essentially flat, whereas the edge of the glass blade remains a definite sharp angle.
30 angstroms is 0.003 microns
Compare to general size of viruses ( Hepatitis A, rotavirus, Norwalk virus ) of 0.004 microns
and steel 7,7496,7595
An as sharpened edge will typically be between 0.1 and 1 microns, for reference 100 microns is 1/10 of a mm which you can easily see by eye, so an edge will start reflecting light in the range of 10-100 microns and by this stage most people will consider a knife very dull, assuming they can sharpen knives as it is then < 1% of optimal sharpness.

I don't mow smiling smiley

Edited 1 time(s). Last edit at 12/06/2015 04:19PM by ShaperAndMower.
Re: Obsidian/Glass as a Cutting Edge
December 06, 2015 06:31PM
I think they use obsidian for plastic surgery, and when some people have scarring issues (such as keltoids) but I haven't read or seen anything for a long time, so I am not sure if it's still in use.

"Gotta love living in 2019 baby, (63rc too soft on a production knife)"
--Shawn Houston
"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp
"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes
"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser

Jason D. Stone on YouTube
Re: Obsidian/Glass as a Cutting Edge
December 06, 2015 07:49PM
Well ill be danged. It is still used in eye surgery, as well as diamond scalpel. In fact the Obsidian is the cheaper blade.
Re: Obsidian/Glass as a Cutting Edge
December 07, 2015 04:33AM
I have heard that it is used for people with allergies to metal, I can't remember where I heard that so take it for what it's worth.



Re: Obsidian/Glass as a Cutting Edge
December 07, 2015 05:25AM
Here is a specialty supply that lists diamond and Obsidian for eye surgery.http://www.finescience.com/Special-Pages/Products.aspx?ProductId=287http://www.finescience.com/Special-Pages/Products.aspx?ProductId=296&CategoryId=56 Now they cater to the research side, but that is wild. I'm going to do a little more digging, a lot of my family is in medical field either in practice, research, or both; so they may have some more direct info.
Re: Obsidian/Glass as a Cutting Edge
December 10, 2015 06:56PM
In doing some research on this (yeah, I posted in this subforum with a question I could likely have easily answered on my own. It's pretty ironic), it doesn't seem to be the case that obsidian or glass has any significant benefits over steel for surgical applications or other cutting tool needs, in terms of scar tissue reduction, tensile strength of the wounds after healing, or any other significant issues.
Re: Obsidian/Glass as a Cutting Edge
December 11, 2015 01:31PM
the spy/terrorist novel i just finished, one of the bad guys was able to smuggle an obsidian knife aboard a plane and try to hijack the plane.
Re: Obsidian/Glass as a Cutting Edge
December 13, 2015 10:38AM
Interesting. The article I have (just one) shows higher strength of the healed wound when using an Obsidian blade. Perhaps they didn't try a really sharp steel blade.
Re: Obsidian/Glass as a Cutting Edge
December 13, 2015 07:26PM
They are much sharper than a steel blade, about 3nm thick apex. What I've read so far has said that there wasn't a significant difference in wound strength or scarring past a certain number of days though. They did make note in a CNN article that the obsidian blades are sharp enough to cleanly split individual cells.


Re: Obsidian/Glass as a Cutting Edge
December 13, 2015 09:26PM
One of those is the one I'd read before with wound/scar strength between 1.1 and 2.5 times that of the steel blades wounds/scars. However, it was at 14 days. I had not read anything beyond that in healing time, and it appears that by the time both are fully healed, there is not a noticeable difference.
Re: Obsidian/Glass as a Cutting Edge
December 14, 2015 07:35PM
It would be highly interesting to me to work with a blade that sharp. I found scalpels for sale but the expense is pretty high if you consider the consequences of lateral loads. I'm honestly considering buying one because I want to see what that level of sharpness is like, I can't comprehend the ability to cut individual cells cleanly in half. It's fun to imagine.
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