Sometimes some things need to brought home as a conversation piece.

Hah, cool. My Dad would always bring home stuff like this either from garage sales or stuff he came across buried in a field while working (he worked digging up old storage tanks for awhile), the whole family would fiddle with it and try to dream up what it possibly could have been for. (This was pre-internet, so we often had no idea what we had.)

I wouldn't have guessed this one, but I would have enjoyed playing with it, LOL.

I took a film class in high school, and that little flip thing on the end of the spindle is what would hold your film reel on the rewinder.

https://www.google.com/search?q=anti...ie+film+winder

There are several here mounted in twos on boards. I think a film editor would need these to move the film back & forth.

I bet the clamp one (the OP's hand crank) was for movie theaters. They would only need one, to rewind the reel back so the beginning of the the film is in front, to send it on to the next theater.