This is what the final design of the detailing on the reel should look like. I laser cut it out of two pieces of cardboard so that I didn't waste time etching out all the detailing. I think the dimensions are right and will fit nicely with the rest of the part.
It has been sized based on the dimensions of a viewmaster card. This way it means there are the right number of holes on the front and people should be familiar with the design. This might even bring back memories to older users.
^^ the part where the conical feature would be situated
^^ the other part where a cover hides the bolt which keeps the part together and allows it to rotate.
^^an idea of what the part should look like. This would all be manufactured as one piece to allow a seamless transition from the feature to the reel.