blade that can slice through anything?

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Have any of your every heard of metal whiskers? They are sometimes formed between electrical wires on micro chips. They are perfectly formed crystals and the ones made of iron withstood 150 times as much force without bending as steel. Unfortunately they are very tiny but they would be great for the leading edge of the blade.
Ok, I know there hasn't been a post here for over a year, but I looked the thread over and there are a few things here that could stand some clarifying.

First, Japanese weaponry. Through various means (smelting technique, composite (different types of iron and steel) construction, and surface hardening (actually edge hardening)), traditional Japanese swords had a very hard and somewhat brittle edge integrally connected to a much softer and more flexible back. The thick back provided strength and suppleness, the hard edge could be polished to be extremely sharp and to retain that sharp edge for a long time between sharpenings. This produced a weapon that was well-suited for the demands of combat between foes wearing various types of segmented or laminar armor. The super sharp edge was also very effective against unarmored foes.

However, the secret to the cutting ability of this weapon is the edge. To the naked eye, it appears to be as smoothly polished as the flat of the blade. However, under a microscope, tiny nicks, breaks, and chips in the last micrometer of the edge can be observed. These had the effect of providing a "micro-serrated" edge. As any afficiando of these weapons is aware, they cut soft materials much better with a draw cut than with a straight chop. The micro-serrations effectively turn the edge into a sort of molecular saw. Not bad for technology developed several hundred years ago.

Most other ultra-hard materials mentioned in this thread (especially diamond) have the disadvantage of being very brittle. As the gentleman who handled professional grade ceramic knives in the kitchen mentioned, these have very sharp edges and cut very well, but cannot be handled carelessly lest they shatter. This is typical of all ceramic materials due to their fracture stress properties. Although diamond is not strictly speaking, a ceramic, it's extreme hardness allows it to behave as one. The problem with brittle blades, of course, is that when struck against a hard object, they have a high likelihood of breaking. This is especially true for any blade used as a hand-to-hand weapon against similar weapons. As we see, both the European and Oriental swordsmiths weren't stupid!

One possibility seems to have been overlooked. There are several processes that can embed small pieces of diamond, of the scale of the "serrations" in the Japanese blades as described above, into softer materials. I should point out that the hardest steel imaginable is still much softer than diamond. With proper polishing, these bits of diamond would form a shape similar to the points of the teeth of a saw, with the softer metal between them wearing to form the voids between the saw teeth. I don't recall that anyone has every tried to create a practical cutting instrument using this technique. The technology is quite simple and available today, should anyone wish to try it.

Nanofiber technology is intriguing for the role of a cutting instrument, simply because a thinner edge is easier to push through a material than a thick one, and the maximum possible fineness of the edge is determined by materials properties. Nanofibers, which hold the potential for very high specific strengths, lend themselves to this. However, I feel some sort of serration must be introduced to the edge for the reasons pointed out above. It may be possible to eventually construct a blade composed mostly of nanofibers oriented in the long direction of the blade, but with a few "sawtooth" nanofibers or embedded diamond crystals "grown" in a direction perpendicular to the blade.

There was mention of nuclear weapons cutting through anything, or not being able to do so. Nuclear explosives have two properties of interest to us here. First, they release enormous amounts of heat. This heat load will cause any material known to man to vaporize, provided it remains in the vicinity of the explosion. They don't so much cut their way through objects as melt (or vaporize) their way through.

The second property is that a nuclear explosive detonated in a gaseous environment such as earth's atmosphere produces a shock wave in that gas, expanding outward at high speeds (initially, supersonic speeds) from the point of the explosion. When this shock wave encounters frangible items such as poorly-reinforced concrete buildings, those items are fractured and literally blown away by the high-speed winds accompanying the shock wave. So, a concrete wall that is too far away from the explosion to be vaporized or melted may still be smashed by the shock. Note that this shattering mechanism doesn't work in the vacuum of space. Again, the nuclear device doesn't so much "cut" something as "break" it.

There is a rather fascinating exception to this. During one of the US aboveground bomb tests back in the 1950's, two large (~4 ft. diameter) iron spheres, coated in graphite for thermal protection, were placed next to the test bomb on either side. After the detonation, they were found roughly 1/2 mile from ground zero in opposite directions, little the worse for wear. The explanation is that the high blast force generated by the bomb was enough to propell them away from the explosion faster than the massive heat release could melt through first the graphite coating and then the iron underneath. Being solid spheres, there was no internal structure to be crushed by the blast. Effictively, they behaved as giant elastic tennis balls...or baseballs, if you prefer that analogy. This test was part of the rationale for the Orion project, a concept for pulsed nuclear spacecraft propulsion that was conceived back in the 1960s but never built.

The point to all this discussion of nuclear explosives in a thread about cutting devices is that any sort of plasma device, that is, a "light saber" would "cut" by the same mechanism as a nuclear device: extreme heat. I suggest that any such device powerful enough to cut through say, a bank vault, would either emit so much thermal radiation that it gave the wielder third degree burns, or else the thermal energy would be so well contained within the "blade" of the device that it might to be difficult to detect the heat leakage if you placed your bare hand an inch or two away from the "blade". I suppose it depends on what sort of plasma and heat containment technology you postulate for such a thing.
Someone mentioned water jets, and that's the right track, especially with abrasives, they can cut through alot, but need to be slowed down at the other end by a tank of water or something.

Actually in use in industry are plasma jets, which cut with a very hot stream of plasma. They are working on something now (don't ask how I know) which cuts with a stream of molten iron, which is maintained in a superheated state by a current of electricity running through the stream itself.

It would be extremely difficult to make it into a mobile sword-like object. The more powerful a stream of anything would be, the more it would cut into anything that stopped it after a certain length. If there was a material or force field that could stop it after a certain length, then that material or force field could also be used as a defense.

And, it's also silly to have an extremely powerful weapon with such a limited range. (No substitute for a good blaster at your side)
hiimwayne said:
I'm sure alot of you have heard about swords or blades that are so sharp, they can slice through anything. In fairytales such as excalibur and video games that is. My question is.. is it possible to have a blade that's sharp enough to cut through anything? What would be required to build such a weapon?

if you propel anything fast enough at any object it will slice through it, no need for dimond blades... whoever thought about that one dosnt realise you dont get long dimonds in that size, or the fact that they really DO shatter if hit by a hammer.
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ok, diamond blades.. this wudn't work. lets say u did find a diamond large enough. u make a blade out of it, and sharpen it up. u'd never be able to weild it. the weight wud get to it b4 u get to even try and shatter it. the whole idea of a diamond blade is stupid. now, a single molecular edged blade is what u want. problem is, it wud be to "weak." it wud break easily due to the incredable thin edge. scientist have actually gotten pretty close. down to a few molecules of steel or so, thanks to diamond and laser cuts. but there is no single molecular sword. the best swords that have exsisted were the ones made back in the 1400's - 1600's by the japanese. these were the best swords, and went completely unrivaled, up until the 20th century.thats wen we discovered the diamond and laser cuts. we took the same swords and made 'em better.

A lightsabre. great idea. problem with it, well, plasma is to hot. the only way to make plasma work for this is to "package" it wih an electro magnetic feild. then there's the problem of, the feild itself. the feild wud hold in the heat and everything, but the problem wud be that the feild wud also repel anything else. and by that i mean, u get the "futurama lightsaber." were u get the cool look and effect, but it work just as good as a baseball bat or nightstick.

The "sharpest" thing we have out there right now, is a laser. the laser's we have can cut through anything, just about. steel, rock, you name it. lasers are what we use right now to cut diamonds for rings. diffrent wave lengths cut, and polish the diamond. so those are the sharpest things now. and really, they're not sharp, they just use heat to cut things.

so overall, a single molecular sword wud be the thing to cut through anything. but we dont have the technology to crete one right now.

(please excuse the spelling, it's now 1:30 where i live, and i'm very tired. thank you for your time).
Actually, diamond only shatters if you hit it in exactly the right place. All the pressure has to be in one very, very small place for it to shatter. The edge of a blade would be made so that there is no shatterpoint. It has to be hit at a vertex for it to shatter.

But perhaps a carbide blade that is diamond-encrusted?

These blades sliced through the hearts and prejudices of America and the world.
Please explain what a plasma blade is, and how exactly that would be constructed.

I envision plasma blade as a tool that is held on a metal stick which has half of its length for plasma creation.


image shows a similar project for the creation of a plasma gun.
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