A Knife On A Rope…

A long while back, Sinza, a friend of mine who runs the Exotic Automatic Forums, suggested I look at on one of the weapons used in the movie Blade Trinity. Specifically Blades Chain Saber. At the time I wasn’t too keen on posting about it because, from my perspective, it was an Epic Phail of a weapon.

However in retrospect, I probably should have done it, because I do just as much griping about flawed weapons on this blog as I slobber over the cool ones. (My bad, man, my bad… 🙂 ) So when I happened to run across it again, I thought it would be a good time to rectify my mistake. And also point out why I didn’t like it.

Chain Saber

Blade Trinity: Chain Saber

[click image to view full size]

So what we have here is a knife on a rope. Kinda like a Soap on a Rope, but not quite as useful. Essentially what is a wide split blade with a rat tail tang, attached to a length of black elastic, that is connected to a black and chrome grip.

When retracted, the blade locks to the handle/grip. The grip has a set of buttons, one cosmetic, and the other functional which releases the blade.

Now this is certainly an interesting design, with lots of potential. I cannot argue that. A blade swinging around at the kind of velocities you could generate with something like this would be quite the formidable weapon. The only problem I have is that this replica gets all the important parts horribly, horribly, wrong.

Take the elastic band, for instance. Mating a piece of steel to some fabric covered rubber is never a good idea, expecially in a high stress environment. Mr. little rubber bungie cord is really is not a particularly tough fellow, and when made to rub elbows with Mr. Steel, a rather notoriously hardened chap, well… Bad things can happen.

Just picture a Wiimote going airborne and becoming embedded in wide screen TV. Except with a hunk of sharp steel instead of a small plastic brick. You get the idea. Not good. especially if you like wide screen TVs. Mr. Bungie was a good man. Pity he just snapped like that. Please do accept our condolences Mrs. Bungie… A moment of silence please… Ok… I’m rambling aren’t I… Right. Back on topic.

In fact, the weapon used in the movie employed a chain with a retraction mechanism in the handle. A much more sensible implementation. But it too, suffers from a rather insidious design flaw. Have you ever tried to swing a blade on the end of a chain? I have. Really fun. Except for one thing.

Unless you are using a quad edged blade, your chances of hitting anything with the *edge* of your blade are about 50/50. If you are good, you can get the point to bear fairly reliably, but edgewise strikes… Meh. So the way it is used in the movie is… You guessed it! Magic!

If I were designing such a blade, I would do one of two things. Either use a chain that is rotationally stable about the lengthwise axis of it’s links (like a bicycle chain), or use a bade that will cut no matter what  side it hits. IE use a quadruple, quintuple or sextuple edged blade.

Personally I think a fine, highly flexible, high tensile cable attached via a freely articulating joint to a quadruple edged blade would be the best design solution for a weapon of this nature. Especially given the design challenge of fitting a retraction mechanism into the handle. But that’s just the design nerd in my head talking.

What’s funny is the site I found this on touts the replica as an “exact” replica of the original. huh? *Exact*? Are you saying a fixed bungie cord is *exactly* the same as a chain attached to a button activated retraction mechanism?!? I think not.

Either way, great concept, not so good implementation, and total humiliation on the replica. Certainly cool to look at, but I really wouldn’t try to swing it any harder than you would an ostrich feather…

“Exact” replica… Pfft.

<Inigo Montoya>This word. I do not think it means what you think it means…</Inigo Montoya>

Blade Chain Saber – [Kingdom of Swords]

11 Responses to “A Knife On A Rope…”

  1. 1 Stilllife
    November 14, 2008 at 2:55 pm

    I saw a version of this on TrueSwords, and I remember that the length of the cord was only 6 inches, hardly a useful weapon and hardly a good replica considering Blade’s weapon extended to about 10 feet.

  2. 2 beanjavert
    November 14, 2008 at 8:12 pm

    Saber? lolwut?

  3. 3 Pzyko
    November 17, 2008 at 12:44 pm

    Why pick a blade for swinging around on a chain? Might aswell pick a proper flail and beat the living crap out of whatever you might find worthy of beating 😉

  4. November 20, 2008 at 10:19 am

    I have this within reach…it’s a neat toy, but not what it could be.

    What we have is three different versions of this knife.
    1. The original idea of what this is supposed to be and do.
    2. The movie prop used on film.
    3. The collectors replica prop.

    #1: A ballistic knife with a retraction cable. The design is actually fairly simple. If you used something like a retracting key chain installed in the handle and used the same design as the Russian ballistic knife for projection. The springs I’ve seen in ballistic knives are more than enough to throw the blade out to the length of the chain, even against the retraction coil spring. So in my opinion if you really wanted to make a knife of this design you could make it work. This would work for the first move that Blade does in the movie where the blade shoots out and stabs a person. You might be able to tug it out and have the blade retract. Not very probable, but it might all work. The spinning around and whipping the blade I don’t see as being very effective. The big difference would be the chain length. The movie showed a chain of at least 10ft…I don’t see a real model being used with anything more than a 3-5ft chain.

    #2 In the movie, what isn’t CGI is the movie prop. This wouldn’t have to be anything more than what they sell us as both times it’s seen it’s assembled /or fixed blade knife.

    #3 Now about the collectors prop….It’s not too bad…and here’s why…
    Ballistic knives, knives where the blade is ejected out of the handle, are the most illegal knife. Period. I think almost any counties that have laws have banned this type of object. Shooting bullets is o.k. but you can’t spring out a blade. Ballistic knives are federal prison type of illegal.
    With that being said my opinion of the Blade replicas is that they are great for what they are supposed to be, room decorations movie memorabilia. The cost is what?? $40? $50?
    I bought the Blade sword ‘Sword of the Daywalker’. It looks cool. I swung it lightly and tapped a cardboard box and the blade tang broke in the handle. It was made so crappy. But again, it was just made to be looked at and not a ‘real’ sword.
    Now…if you wanted a real Blade sword, something that would last years of real battle use, this would cost hundreds or thousands of dollars. Take a good look at real quality sword makers, how long it takes, the steps involved, and the real price of quality.
    Ballistic knives also are not cheap…except for the cheap crap ones of course…
    I’ve seen Ballistic knives for sale over $1000. If you wanted a real ballistic knife with retractable blade chain this is something that could be made but would not be cheap, I’d say $1000-$3000 for a quality machinist/knifemaker to build it. Thing is very few people will even dare to touch ballistic knives..very taboo.
    So, in my opinion the Blade series of weapons is great for collectors to look at but that’s all.
    This is a well made prop for those that want to own one, but it is not a real knife. It’s not sharp, it has no chain, and the blade does not launch. But it looks and feels cool and looks nice on a desk.
    A real version of this chain-sabre could be made, but I don’t see it being very useful. I’ve played with ballistic knives and they are very limited, adding a retracting chain would only add more limitations. A fixed blade is always the best.

  5. December 8, 2008 at 5:31 am

    Yeah, that was my other complaint, length wise, you’d be better off with a short sword than this…

    heh… yeah… doesn’t look much like a saber now, does it… Sometimes i wonder what they are thinking when the come up with these names…

    Well, functionality wise, a heavy blade on a chain would do more damage than a simple impact weapon on a chain. Provided, of course you can design it properly…

    Excellent analysis. I suppose if I were a manufacturer trying to replicate Blades weapon, I’d be trying as hard as possible to stay away from the heavily illegal aspects of it’s design. However they also took out one of the cool aspects of it too.

    You don’t need to have a spring loaded blade in order to put it on a chain. Blades on a chain aren’t illegal, just spring launchable blades… I wish they could have at least tried to put the blade on a chain with retractable key chain thing or something at least… That would have been cool… 🙂

  6. 6 jeff
    January 30, 2009 at 5:49 pm

    I LIKE CATS! ^^

  7. 7 FAB
    February 15, 2009 at 11:20 am


    My very first post.
    It is going to be a bit long and technical so please bear with me.

    First, about the blade design:
    There is absolutely no rational for making a two pointed blade. My deepest apologies to Gil Hibben, who first made this design popular (see some examples at http://www.hibbenknives.com/). But although double points may look very cool and aggressive, they are completely useless as fighting blades:

    1 – the gap between points weaken the blade structure compared to a classical design. If weight reduction is the objective then it is better to make a fuller or cannelure on the spine (or even hollow out completely the center of the blade) rather than split the point.

    2 – actually reduce the penetration factor. In addition remember that the wider the blade the less it is appropriate for stabbing. As a rule of thumb, wide blades are better for slashing; narrow blades, or even ice picks, are best for inflicting puncture wounds.

    3 – And having two points almost guaranties that they will get stuck on a rib (probably very painful but not incapacitating) instead of sliding between the ribs to hit a vital organ.
    So even before getting to the extensible cord part this is a pretty poor weapon.

    Second, functionality:
    I have not tried the actual prop. But I have played around a couple of very similar constructs. Here are a few very important facts to remember for those with an adventurous mindset who might be tempted to experiment in the field with this concept either with the prop or similar gadget. Basically this applies to any “blade on a chain” system(remember, I speak from personal experience here):

    1 – Having a cord tied at one end prevents the knife from rotating in the air, so forget about any knife throwing technique. The only way to send the knife to any meaningful distance by strength of arm is closer to the motion used for fly-fishing. Accuracy is, shall we generously say, “approximative”!

    2 – Slightly different problem if it is spring-loaded: first the unspooling of the rope/wire would slow down the knife quickly, the weigh itself of the wire would tend to modify the trajectory of the blade (a common problem with harpoons for example). More important for the weapon to be effective in its “flail mode” it must perforce be blade heavy… but if it is blade heavy the spring can’t propel it far and strongly enough to be any use… it is a catch22…
    All military spring-loaded knives (the NATO official term for those is “ballistic knives” or “pilum-knives”) send fairly small, very pointy, almost dart like blades or a kinetic baton (or a grapnel to make them legal in the US). In addition despite the fashion hype when they became available from Russia in the 1980’s, the effective range of those knives was little more than 2 meters (about 6~7 feet), and with mediocre ballistic performances to boot. At that range you are much better off by throwing loose change at the opponent’s face with your left hand (thus provoking an automatic blink reflex) while simply closing the distance to slash with the knife still in your right hand, this technique was taught in Steve Ryan’s knife-fighting seminars to handle opponents at just that engagement distance.

    3 – twirling a blade in the air, especially a wide one, at the end of a cord will automatically make it spin on itself like an helix. So if you have a vision of the blade slicing through the air with its cutting edge horizontal you can forget about it. What does happen is that the blade will most probably hit the target flat… a rather useless result since not only it obviously will not cut but it also spreads the impact force over a wider area thus reducing potential blunt force damage. Sorry dear Phyreblade, a heavy blade on a chain will not cause more damage than an equivalently heavy impact weapon. To get maximum lethality, what you want here is a lozenge shaped striking weight (or a slightly spiked ball) so that the impact force is transmitted over a small area.

    4 – Ok, enough with the serious technical stuff, this is the point where I almost got a Darwin Award for my efforts at field testing… so pay attention:
    no matter what spooling mechanism you want to use to bring back the blade into the tube (or into your gloved hand if you use a forearm mounted version of this system…), please note that it is a VERY-VERY-VERY BAD IDEA to believe that the blade you just jerked back toward yourself will actually return to its proper place. IT WILL NOT!!!… Instead it will backlash brusquely toward you much faster than the spooling mechanism can rewind the wire. Thus letting you discover another, as yet unmentioned, disadvantages of double points: if you are unlucky enough you might just be able to gouge out both your eyes at the same time instead of just one when the blade snaps back toward your face.
    In my case, thanks to some serious protective wear and quite a lot of wisdom gained (painfully) in similar try-outs, all I suffered was some minor frights and some very painful bruises on the knuckles: When it does work and even under the best conditions, the final few inches of rewinding are always problematic. Provided you do not otherwise maim yourself or an innocent bystander, then the most likely injury will be from a “folding nunchaku” effect as the blade does not get back into the tube as planned but instead pivots at the mouth of the tube and comes to whack you on the hand holding the handle. Hence demonstrating the usefulness of wearing reinforced gloves (buy the prison guard type, they are fairly cut resistant, and have carbon-fiber insert protecting on top) and of keeping practice blades less than fully sharp.

    5 – Oh! and unless you plan to use it only in empty parking lots or on football fields, please note that any weapon on a long cord/chain/wire is a little difficult to yield without having it catching on everyday mundane stuff like branches, walls, cars, lampposts, garden furniture,…

    So in short I would give the chain saber concept a 0 out of 10 for design and a minus 3 for functionality (more dangerous to the user than to the target)…
    Finally, and this is a purely personal aesthetic opinion on my part, the movie prop just doesn’t look very good to me… compared to some of the nifty design otherwise seen in the trilogy, this piece is way below par.


    * Avid amateur of edged and blunt weapons, and practical realist about their uses and limitations.
    * Moderately talented engineer (more enthusiasm than skill…)
    * Fearless tester of sharp stuff (more enthusiasm than brain…)
    * Hopeless seeker for an earthly equivalent of the Holy Grail of Knifemakers: the Lightsaber… The only weapon that will go through any material and that can slice from any angle and any side! And, when turned off, it fits in a pocket too!!!

    Note: If my comments, now and in the future, may seem unclear or overly complicated, please forgive me as I am not a native english speaker and some things do get lost in translation…

  8. 8 shirkeneater
    March 4, 2009 at 8:16 pm

    ya i would rather use the things i am so prone to eating, than this i gess if you were to make a rely good one not a pece of steel tied to a thin bunge cord


  9. 9 nomy908
    June 16, 2011 at 2:19 am

    just saying so this wont be a comletely negative thread it could be greatly improved by adding another cord parallel to the first to stabilize the swing and the blade mid-swing and also as for the handle a pommel would be fantastic to save your hand as it retracts

  10. 10 kuu
    August 24, 2011 at 3:37 pm

    This is definitely fail like you said, but there are many more reasons to it than what you post, the concept of adding a cutting counterpart to a whip is totally win, like you said the speeds a whip’s tip can acquire are formidable win, i think i heard its around the speed of sound, if you add a (fail url tag?) http://movieclips.com/NRnW-underworld-movie-whip-vs-werewolf light edge to it it might be fragile and not suitable for long winded combat but the damage potential is….. ouch. Still adding a very heavy tip is fail because that would slow down the speed, and like you said it would be harder to hit, adding anything heavy to a retractable weapon like that would be incredibly phail because it would make it slower and a dagger on the tip of a whip wouldn’t stab too deep like a deep with a rigid handle could.

    The only rope mechanic weapons so far afaik have been the flail the ball and chain flail the kama and the whip, this doesnt follow any of the concepts that make the weapons grand. Its concept is plain fail for all the obvious reasons of having no inherent strenghts, just range, and if its range you want get a whip a bow or better yet a gun, i guarantee they will do more damage…

  11. May 27, 2013 at 9:22 pm

    What’s up to all, how is all, I think every one is getting more from this web site, and your views are nice in support of new visitors.

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