An iris mechanism for storing a Canadian engineer's iron ring. Mechanism is print in place.
print at 70% for my iron ring, YMMV
The cam follow can be lubricated with silicone food grade lubricant for smoother motion.
Removing the supports from all the nooks and crannies is time consuming, but the mechanism should function once freed.

You can also see my updated design: https://www.thingiverse.com/thing:7288904