We have a 8mm/Super8 projector that requires reel adapters to use Super8 reels. Adapters can be hard to find, or hideously expensive for what they are. This is a printable adapter.
There are several different designs of adapters available, and this was based on one that I purchased to use Super8 reels with my wife's projector. I printed it in PLA and it fits on the spindle and in the reel just fine.
Super8_Reel_Adapter.stl | 326.8KB |