Need help with my hidden blade design.
Okay, so I'm thinking of making a hidden blade (Assassins creed style) and i thought a copper tube with a smaller copper (or pvc) tube inside would do for the sliding mechanism. To make it not slide with everything I put a weak magnet on the bottom so it will only slide with some force. The braking system (so the blade wouldn't fall out) is a rubber ring at the top that will let the blade through but not the copper tube. The only thing I need help with is the system that will prevent the blade from going back in the outer-tube. So plz help me with a design for that. I don't care if I have to put a switch or something to get it back in, it doesn't need to be with 1 hand.