Interesting discussion! One of my fellow training and performing partners linked me to this topic. Me and my group are doing an Assassin's Creed promotion performance for Ubisoft next month and we're planning to construct and use this weapon in the show.
So far I've designed a simple model using springs to "launch" the blade. For it's purpose of being a stunt weapon the mechanism won't have to lock while the blade is out (so you can safely "stab" someone), but a locking switch could be implemented. There is a lock to keep the blade inside, but it will have to be opened with the other hand. (In one of the game trailers, it is shown the dagger mechanism is activated by pressing a button with the other hand as well). In my design, it'll be more like pulling out a pin, but I realize there are more subtle ways to do it.

Here's a link to my "blueprint":
http://northernwind.arandoir.com/images/ACspringblade2.jpg

Anyhow, this is only a simple solution/imitation in which I'm only able to get a total outside blade length of 15 to 18 cm. One of the game trailers shows a complex mechanism with gears and stuff, but apart from giving a sophisticated and fancy look, I wouldn't know the purpose of these.

I'll start working on it by the end of this week. I'll keep you updated if you're interested. Suggestions are also welcome of course. ;)

Hmmm... looking at the reference picture in the first post, gave me an idea. Maybe the bladelength could be doubled by applying a "telescopic"-like deployment.

I'd agree with Jean that, in an open fight, the blade would have the significant disadvantage that it can't be easily transferred to an icepick grip or to the off hand, but it might work for a surprise attack where the assassin needs only to stab once against an unsuspecting opponent.

I keep wondering about the game's concept of the assassin, though. Most fantasy (and even historical) assassin games and stories nowadays tend to assume a single stealthy assassin, whereas the historical evidence tends to favor the employment of multiple assassins operating as a team--and in many cases these assassins were little better than thugs. I'm not saying that assassins can't be skilled, though. It's just like I wonder why the assassins can't use more teamwork in those games and stories.

Horribly off-topic, I know. But it fits the title of the board. ;P

updates would be awsome. your design, does it have a spring or similar mechanism for retracting the blade or do you have to do that manually?

I was delayed a bit by exams, but I got most of my materials now.

There's a slight modification in the plan. If it all works out, the blade will be launched by stretching the hand backwards (using a string connecting the unlock mechanism to a ring.

I haven't put much thought in ways to have the blade auto-retract. Though it would be really cool, I'm afraid it'll over complicate the model and I'll never finish it in time ; ) .

I don't think this could be done with a spring mechanism. However, it could very simply be done with just a pressure fit. The blade is held in place by friction, then deployed with a sudden arm jerk. The blade would then lock. But, you would have to draw it back in manually.

Having on the underside of the arm is quite impractical. If you were going to make one, it would have to be on the top of the forearm, so the blade comes out on top of the wrist.

I am currently building this knife from sheet metal I got from Lowe's.

i don't think that practicality matters all that much. it's the design that is of import. if needed it can be modified to sit comfortably and safely else where.

Hmmm... regarding a "retract-mechanism": I came upon this last night:

http://www.youtube.com/watch?v=7VLSMxlF5gY

This "pull back" type of action that also resets the spring looks like it could be done relatively easy. However, it wouldn't be really practical for use under clothing, unless there was a way to pull it back without undressing ( If the handle would not extend past your elbow and could be gripped through one or two layers of clothing it might be doable, though still a little impractical).

watched the link and it's not a bad idea for a hand held, it gave me an idea (dunno if it would actually work). if the extending mechanism also charges a retraction mechanism that coud be activated with the other hand. just thought i would throw the idea out there.

Hello everyone, I have been obsessed with this game from the day it was revealed to the day of completing it yesterday.

But you all have it wrong
you seem to believe that this is a historical weapon that needs to be taken extremely serious, if you have played the game you will know that he activates the blade two ways, closing his fist and pulling his hand back.

In a painting done by the artists at ubisoft, the mechanism has a piece of leather that comes out of the spring mechanism and attaches to a ring on his pinky.

Now in the game, he can send the blade out and somehow pull it back in without touching the blade or mechanism with his free hand, so if youre going for authenticity you would need to come up with some design that allows you to eject and also bring the blade back into your arm. Altair in assassins creed is able to use the dagger to counter attack enemy attacks by dodging and stabbing with the hidden blade, however when you try to use the hidden blade to front on attack and counter then you will get majorly damaged by your opponents. But thats why the hidden blade is not used for frontal attacking and defending. The Hidden blade is used for silently stabbing people as if you are whispering something in there ear and you thrust the blade into their stomach, the other way it is used is by jumping up and stabbing into the throat or the spine of your victim, wich you would think defeats the point of using it when you could just use a dagger. However thats why this is a game weapon, when he does the jumping strike with the hidden blade, its meant to be done for example from a large crowd and you suddenly run out and jump and strike your victim.

So I think if you were to make a real one(wich is how I stumbled apon this forum) then you would make it so that the blade only shoots out with a a ring around your finger attached to a strong piece of leather or string, or metal bar of some sort. That would make it so that you can eject the blade without slicing into your fingers on accident. So when you pull the string it would release the spring and fire the blade out, then once the blade is extended the locking mechanism is activated as seen the in the video posted a couple posts above, then just like in that video you have to pull the blade back in using a method similar to the one in the video.

Obviously this is not an effective weapon in todays world in most of your opinions, but thats because you seem to think its for front on fighting. If you were to use this mixed with a long sleeve baggy sweat shirt you would be able to stab someone in the back in a large crowd if done properly maybe without anyone noticing, and you would be surprised with how stupid people really can be when it comes to noticing or caring about things done in public.

I am only 17, so I may not be the most creditable person here, but I have thought and studied this. If you look on google images for "hidden blade" you can find the drawing of how the blade looks and should in theory work.

PS Sorry for lack of grammar, im in a hurry.

"Game thinking here as far as I'm concerned ! Taking advantage of a lost finger might make sense but losing a digit to be able to use a specialized weapon that would have few if any advantages compared to just pulling an ordinary dagger, just doesn't seem useful or rational to me !

Now, as some sort of weird " initiation " it might make some sort of sense but only because " secret societies " can have all sorts of odd traditions.

Oh, and a little good design work would make the mechanism work safely without having the design being dependant on missing a finger if one still decided that the idea what worth it !

A very powerful ballistic opening could be used to power the thrust it self as opposed to just deploying the weapon and having the hand thrust forward: Could open and close faster than the blink of an eye ! So, as an assassination tool of surprise weapon it might still be worth the trouble.

Oh, and back to the loosing of a finger: Deliberately weakening one's grip for use with ordinary weapons is another reason to think that this is a bad idea in real life ! But in a game why not. "


Jean youve got some interesting stuff in all your posts, and this post is really quite interesting in the sense that it has touched on so many aspects of certain attributes of this weapon!
I was playing Assassins Creed just the other day and find it a fascinating game in its own right, the initiation you mention, the loss of this particular finger may act as a sort of reminder or a permanent state of service to the Assassins Creed by losing this finger to attach the mechanised dagger.
The fighting in the game I think is also quite realistic in the sense that you can do nearly anything to disadvantage your attackers or pursuers the dagger in the game is used for stealth assassinations which is probarbly one of the most important parts of the game.
You mention the loss of grip and strength in the left hand for other weapons? He doesnt use any other weapons in his left hand apart from the throwing of knives from pockets on his belt and shoulder so I guess it doesnt prove much of a disadvantage, there is a grapple move you can use which simply throws your enemy back making them stumble and fall to the ground, this is done with the left hand, you can still do this with three fingers and a thumb. :D

I hope I havent gone too far into the content of the game rather than the weapon in contrast.
P.S in relation to the LEGO dagger, its most likely that it doesnt have any mechanism at all or so it seems to me as he has to lift his arm into a verticle position to retract the dagger, this may lead to the conclusion that he has some sort of simple harness that stop the blade falling too far, but he has to flick up or down to retract and bring out the blade.
:D IF ANYONE HASNT PLAYED ASSASSINS CREED I GUARANTEE THAT YOU WILL ENJOY IT, YOU SHOULD GO AND TRY IT OUT HOWEVER YOU CAN! Its also very historically correct, in the interviews with the producers, they say that the cities and weapons were deesigned and produced on the game with historians to ensure historical correctness.

Signed up just to post this for ya'll, this is the official art for the dagger mechanism, it's a 3-part blade, double spring loaded(for retractability) and the pinky controls if it's in or out(extended pinky = out) (retracted pinky = in)
[ Linked Image ]

"official art"

[ Linked Image ]

that is just an early concept sketch, but pretty "to the point." quite literally too, around these forums. either way, it's fictional, so anyone could make it look as though it were able to do anything. notice how in the picture above there seems to be no real locking mechanism for the 3 parts of the blade. oh well. again, one of my favorite pics from the game's concept art (i too found this website because of Assassin's Creed recently), but not really official. if i came off as a douche or anything, deal. i won't argue.

Y. Kuipers is probably still asleep so I'll post this for him (sorry Youval):

This is the blade he made:
http://www.youtube.com/watch?v=wy0TqtvAwjw

Though here it isn't finished yet.

And here is a registration of the Assassins Creed promo-show we did with this blade last weekend on a computer game convention in Utrecht (NL):

http://www.youtube.com/watch?v=oleIAOaFvOA

Finally, here's a picture (phone quality unfortunately) that I just have to show off:

http://i6.photobucket.com/albums/y239/RedfangBB/DSC00080.jpg

Thanks Reinier ;)

I will soon upload a vid of the final version. It is SWEET, but probably can't even cut through butter. :P

Kenny Hibberds wrote:

So I think if you were to make a real one(wich is how I stumbled apon this forum) then you would make it so that the blade only shoots out with a a ring around your finger attached to a strong piece of leather or string, or metal bar of some sort. That would make it so that you can eject the blade without slicing into your fingers on accident. So when you pull the string it would release the spring and fire the blade out, then once the blade is extended the locking mechanism is activated as seen the in the video posted a couple posts above, then just like in that video you have to pull the blade back in using a method similar to the one in the video. PS Sorry for lack of grammar, im in a hurry.

Funny, I had the exact same idea about using a piece of string! :)
In my version, there's two ways to activate it: a switch on the "elbow side" of the mechanism and a ring in the front linked with the switch with a piece of old guitar-string.

This weapon was designed to work in our show and "stab" other stunt fighters. So the blade isn't sharp and doesn't lock in to place. Still, it had the same effect as in the game and even received a cheer from the crowd.

Okay guys, here's the Video:

http://www.youtube.com/watch?v=s3PwQdaVclE

And here's about all the parts, before assembly:

[ Linked Image ]

That artwork looks really great, by the way. If I have the courage and the time, I might try to construct a segmented one as shown.
Though, the hardest part would still be to make it retract with a flick of the wrist... that goes far beyond my limited mechanical knowledge. :P