Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:1505844.
I wanted an extremely simple key book type thing and all the ones I found were a lot more complex so I just made one. Need to use 8-32 screws of whatever length you want for the keys you have and I used a locknut for the other side. If you have them available, I modeled it around using VEX Robotics screws as I have a bunch in my classroom. Otherwise any 8-32 screw will work. Everything is press-fit to make sure it nice and tight.
Also included are a lanyard holder and a spacer if needed.
Edit: I uploaded a new version of the lanyard holder which is a bit stronger. Mine kept breaking while I was swinging it around so this should help keep that from happening.