I've been using this thing daily for a few years and there have been a few tweaks I wanted to make to the size so it better fits my keys.
Also I printed the previous version in metal fill and the facets of the model really show up so I figured a higher resolution version would be good.
So that's what this is. Props to outcastrc for the original (http://www.thingiverse.com/thing:92847)
I've resized the STLs a bit to better fit my keys and included key hole spacers. The spacers fit in the keyhole (I had to drill a little bit out of the hole in some of my keys) and stop the keys from moving around on the M3 screw. Print one spacer for each key and add washers between the spacers. You could get away with printing one longer spacer.
Note: The individual stls of the sides of the keyring were loaded in cura and the build plate saved as an stl. It doesn't appear to affect the resolution but the combined file is smaller than the two openscad stls. Maybe it converts from ascii to binary or vice versa?
Infill at 30% for metal fill filaments and at least 1.5mm shell, bottom and top layers to ensure a smooth and completely closed surface (metal fill doesn't bridge the infill well hence the small infill). 20% should be fine for other filaments.