Summary

Newer version here http://www.thingiverse.com/thing:930828

I can't take credit for the form factor. Got the idea from the Keyport Keyslide. I liked the idea so i designed a version that can take your keys (up to 3) and i called it the Key Slink. You will have to modify your keys (see picture). Prints without support once oriented correctly.

Instructions

Cut your keys to 10mm height as in the picture above. Once the case and cover are printed, print the key cap, making 2 extra copies. clip the key into the key cap, ensuring the hole in the key slots around the knob inside the cap (may be a little stiff to get in but that ensures the key doesn't fall out). Once the keys are capped, enter them into the case (there is a stop at the front of the case slots so the keys won't fall out of the front). the back cover will go on very easily so you will need to secure it. If you think you will change the keys in the future, you can use two pieces of thick tape (i used friction tape in the picture above). if you think you want a more 'permanent' solution, you can use epoxy like i did. I can add a keychain loop if you wish so just let me know.

Isthan Key Slink - Key holder