Knife made from sapphire

[Jesse B.]

I've often wondered about knife technology which departs from convention in a major way (and yields some advantage over mainstream cutting implements) -- such as ceramic knives. Here, apparently, is evidence of knives made from synthetic sapphire. This is the only link I could find, with pictures and an unsettling blurb about them passing through security: Artificial sapphire knife.
Yes, from the pictures the knife looks like a high-end prison weapon but all that aside it seems plausible. Sapphire is extremely hard (though I've no idea how to begin comparing its hardness to steel,) and sharp enough to be used in microscopic sectioning. One wonders how functional it actually might be as a blade material. I imagine a knife from it could be made incredibly sharp--possibly sharp enough to slice through the space-time continuum--but it has to be somewhat brittle which might invalidate the whole purpose.

Feel free to dismiss this as hoax or ridiculous novelty.

 

[tnt-user]

$$$= Ouch

 

[Esav Benyamin]

Anything from ceramic to glass to wood to G10 to carbon fiber can be made into knives that won't set off metal detectors. They each have drawbacks compared to steel (or titanium or bronze) blades. There are other ways to detect them, like x-rays, and when you do get caught -- oops!

 

[Phillip Dobson]

Might as well just use obsidian or glass blades. They're much cheaper. Corundum may be hard, but it's almost as brittle as glass.

 

[Planterz]

Hard? Yes. Scratch resistant? Yes. Durable? No. It doesn't take all that much to crack a sapphire watch crystal. I can't imagine that the sharp edge of a sapphire bladed knife would stand up very well. Probably worse than ceramic.

Remember: Hardness does not necessarily equate to strength. Sometimes it means the opposite.

If steel was not the all-around best material available for knives, we would be using knives made from other stuff. There's always alternatives, but there's always trade-offs with them.

Of course, if you're goal is to smuggle a blade aboard an airplane (for god-knows-what reason), than perhaps sapphire might be the choice for you.

 

[2brothers]

I made one out of a banana but I eated it.

I'll stick with my metal knives.
(no, that is not my photo or banana)

 

[rifon2]

Some of the very sharpest knives in the world are made of diamond.

http://www.tedpella.com/diamond_html/diamondk.htm
http://labinstrumentsltd.com/

 

[knivesandguns]

I made one out of a banana but I eated it.

I'll stick with my metal knives.
(no, that is not my photo or banana)

ROFL!!! :thumbup:

 

[misque]

ROFL!!! :thumbup:

+1!

They used to make glass knives back in the day. Don't know if they still do, but, the edge was extraordinary on the two I handled.
Now, that sapphire knife looks VERY thick, so, one might have to do a bit to break it in regular use. I don't recommend chopping concrete blocks or hammering on it with a 3lb. sledge, but regular cutting chores would be interesting.

Now, a diamond knife would really be trick.:thumbup:

 

[walleyeguy7]

Some of the very sharpest knives in the world are made of diamond.

http://www.tedpella.com/diamond_html/diamondk.htm
http://labinstrumentsltd.com/

wow those things are the true definition of cutting instrument. doesnt even tear at the molecular level! where can i get a diamond razor?

 

[misque]

Is that awesome or what?!

 

[cj65]

Might as well just use obsidian or glass blades. They're much cheaper. Corundum may be hard, but it's almost as brittle as glass.

I thought he said conundrum.

 

[wongKI]

Would laminating it with CF help the toughness?

 

[Planterz]

Not at the edge.

 

[godot]

This knife was made by Bob Basset

http://bob-basset.livejournal.com/

From the rest of his work, I kind of view him more as an artist than a knife maker.

 

[tiguy7]

Sapphire is Aluminum oxide. India stones are made from it. It is not as hard as Carborundum (Silicon carbide). Boker and Kyocera make white ceramic knives that are a mixture of Zirconium oxide (Zirconia) and Aluminum oxide (Alumina). These blades are translucent and are cheaper and softer than the black blades which are opaque and made of Zirconium carbide. The latter is supposed to be the next hardest thing to a diamond. The whites blades could probably be made transparent, but the cost would probably escalate. I have seen glass knives at antique shows that were made to cut lettuce and not turn it brown. The ceramic blades mentioned above make great finishing steels, but if you use the knife as a steel, don't cut lettuce, apples, etc. with it.

 

[Skytorn]

I read an article a while back about an anthropologist who, using only Neolithic-level tools, carved out an obsidian scalpel blade and had his OWN EYE SURGERY performed with it. That's not only an incredibly level of craftsmanship, but it also takes a pair of solid brass ones.

This got me thinking. Way back when, Aztecs had the Macuahuitl, an obsidian bladeclub where sharp glass bits are set onto a wooden back.

Could we, using modern technology, make something similar? Might we use glass, artificial sapphire, or diamond, and make small blades that are then set onto a steel back? When the brittle edges break away could we simply replace them from like a large box full of these blade bits?

I imagine them to be costly (duh) and inconvenient (duh), but you'd certainly get a cutting power unlike any other AND bypass the problem of airport security since you need the metal back anyway.

 

[sweet_hitch-hiker]

the second sentence-

for example if you care about your right to use your knife anywhere you want.

i didnt know that was a right

 

[Toyz]

Like the rest of you - I feel very uncomfortable when I have to go out somewhere or travel w/o a knife.

But I do not want to undergo the full body cavity search at the airport if they find something on me that resembles a knife and did not set off the detector.

If that doesn't scream "potential terrorist" I don't know what does...

I would enjoy seeing knives made from alternate materials - but will they hold up to the elements and abuse over time?

I'm digging the banana knife...

 

[Bill1170]

Obsidian scalpels are commonly used in microsurgery today. They can take an edge that is sharper than is possible with steel. However, for general use, steel is a lot more forgiving due to its toughness.

The banana knife is a "green" product, when you finish using it, you can eat it. The peel, on the other hand is a dangerous weapon, used as a pressure-activated friction reducer, can lead to injuries and possibly even derisive laughter. Peels need to be properly composted under adult supervision.