So I had some scrap metal lying around and thought I'd put it to good use. It's a very basic design-no springs, no ball bearings, nothing like that. All it uses is gravity and a lock. The beginning of the video you'll see me shaking my arm, I am not trying to extend the blade, but demonstrating that it will not release unless I pull the lock out of place.(Which you'll see when my wrist goes back.) Every hidden blade design I've seen uses a spring loaded system, with a ring&string system, and made from a ball bearing drawer slide. I only use the ring&string in this design which you can see. It is all gravity and a switch. You'll also see my arm go up and shake again, I'm demonstrating it won't retract unless I release the lock again. When the blade comes out, it slide out all the way and is caught by the lock in a small slit in the blade. You can see it. It's not a perfect design, but it works pretty well. Well enough to be a decent cosplay item if I ever can. I do plan on making more of these, more importantly a drawer slide type with the springs and stuff, but for now I'm going to build on this design. Make it more stable and stuff. For instance; the lock on this model isn't of flexible metal. So constantly tugging away at it to extend and retract the blade starts to bend it out of shape and I'll have to manually lock it which I can do with just the hand the blade is on. I like to keep things simple. It's just a case, a blade and a switch. After all, simplicity usually results and practicality. So I'll make another one of these, which I've already drawn out, and start my next model tomorrow. I'll post another video of it when I finish it and/or get some time to do so. Video:http://s339.photobucket.com/albums/n447/Nazo_GFX/?action=view¤t=HiddenBlade.mp4 P.S. I was completely oblivious to the fact I had Assassin's Creed: Brotherhood's theme playing in the back lol. And yes, that is my Onimusha gauntlet I made on my wall there at the end. Card board, hot glue, and paint-fuck yeah.