Help With The Predator arm blade

[DovaJoe]

Well I'm trying to build a arm blade from the original predator that springs out and possible comes back in just wanted to see if anybody had any ideas of possible spring systems or mechanics I could use and some high quality pictures of it would be awesome Thank you

 

[Contec]

Look around the forum at the builds of the wrist blades from the Assassin Creed games. Could be modified to fit inside the gauntlet.