Emergency cash Keychain

thingiverse

A clever keychain design features a hollow shaft large enough to securely hold a rolled-up bill of any denomination. The hole at the bottom is slightly smaller than the main shaft, causing the bill to expand and lock into place when inserted, preventing it from falling out in an emergency situation. You can give this keychain to your kids without them knowing its secret purpose until they need cash urgently. A small groove near the bottom allows one of your keys to be inserted to break off the bottom, making it easy to retrieve the bill. The difficulty in breaking it should discourage you from using it unnecessarily. The sturdy bottom is designed not to break prematurely. Feel free to modify this design to add some extra flair, such as a rocket with engines. Printing at 100% fill will ensure maximum heft and durability. Initially, I planned to fully encapsulate the bill and use the pause function to insert it while printing, but I decided against it due to two reasons: 1. My printer made an unpleasant grinding sound when I tried to remove the print head from the print set incorrectly. 2. This way, you can give the keychain to friends and they can add their own money inside. Here are some tips for rolling a bill tightly: Start with a crisp, unfolded bill and roll it carefully without adding creases or wrinkles. Once it's as tight as possible by hand, lay it flat on a hard surface and apply pressure while rolling in the same direction. Check occasionally to ensure it doesn't spill out of the end like a Chinese Yo-Yo. When you get it nice and tight, it should fit into the 5mm diameter hole at the end and expand enough to stay securely in place.