A Functional Collapsing Knife Prop for Halloween! I have included a spring file, but I purchased a spring below. I'm still waiting for delivery to test it out. The end cap to hold the spring does have a direction to line up with the snap-ins. I will work on creating a better solution.

Uxcell Od 10Mm Id 5Mm Light Load Spiral Stamping Compression Spring Blue - From Ali Express

10/25/17 Update: Received spring and unfortunately it is not suitable for this application. I will try to find a cheap replacement.

5/10/19 Updated: The Handle and End have been redesigned to work a lot better! I still haven't found a spring that works. If anyone has an idea, let me know.