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Make the Predator Wrist Blades - part 4

In this part of the tutorial we make the rubber band assembly that powers this project. We make the blades work!

Part 1 (the beginning) of this tutorial is here




insert rubber band

Snip a rubber band so it is a length and not a loop. Then tie one end of it to the slot in the blade assembly.


Slide into assembly

Slide the blade assembly into the box and then feed the loose end of the rubber band through that slot at the front.


Pull and adjust the rubber band

Flip the box over and take a look at that rubber band you fed through the slot. This is perfect. Now you can adjust the tension on the blades by pulling or slacking this rubber band. Tinker with this until you get the blades to have a nice tension throughout their full range of motion.

You have a lot of flexibility with this. If you need more rubber band you can always tie a second one to this first one.


Tape down rubber band

Once you have the tension the way you want it you should put a know in the end of that rubber band and then tape it down.

The knot helps prevent it from slipping and getting loose.


Extra tape it

Now, to make it extra strong and so it won't slip you should fold that rubber band loose end over the tape then put another layer of tape over the whole thing.

This will insure nothing slips.


Give it a test! Looks and feels good!

Test the assembly


Affix a rubber band over trigger

We want the trigger to be automatic. This means that when you push the blades into the box they lock in place without you having to do anything.


Test the trigger

This picture shows you a bit about how the trigger will work. You push down on it and it will release the blades. But, when you take your finger off the rubber band will push the trigger back down into the lock position.


Put the cover on the box and tape it down like you see here. We want to tape it and not glue it! This is so we can remove the tape in the future, in case the inner mechanism needs work or the rubber band breaks. And notice, you probably will need to remove the toothpicks and the rubber band before taping. Then replace them.

Insert toothpick

Ok! Test it. When you push the button the blades shoot out. When you push the blades back in they automatically lock in place.

Test the action


The wrist blade thumbFrom here you can paint it, decorate it and make some straps to attach it to your wrist. I made a gauntlet for it out of craft foam. You can see how I did that here. (continue)






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