Very cool! It looks like the output shaft has quite a bit of lateral movement, perhaps something like a Schmidt coupling (https://www.thingiverse.com/thing:2336

Very cool! It looks like the output shaft has quite a bit of lateral movement, perhaps something like a Schmidt coupling (https://www.thingiverse.com/thing:233667 https://www.thingiverse.com/thing:233667) could be used to remove that movement and allow a fixed output shaft. I last saw one of these inside an IBM 3890 check reader machine.