Printing the packaged STL will result in 12 spinners, one driver, the rod and cap.
Use the individual files to print additional parts.
Assembly Instructions:
Slide the piece with the hexagonal hole (the driver) onto the rod first - this part will drive the others. Note: It can be installed with the post facing either way, but the following pieces need to match the same orientation (either post up, or post down).
Slide the spinner pieces with circular holes onto the rod, facing the same direction as the driver.
Add the cap at the top to keep it all together.
Adjust the bottom piece by sliding it up or down the rod as needed. The parts should be loose, but with minimal space between spinners. With use, the parts may slide up or down the rod and need occasional adjustment.
Design for 3D printing considerations:
Designing the rod with a hexagonal profile allows it to be printed with the long axis horizontal, affixed to the build plate. The rod can print in 10 minutes vs 50 minutes, if printed with the long axis vertically.
The hexagonal shape makes fixing the driver in place much easier.
Adding rounded edges or chamfers helps the parts fit together, and minimizes or eliminates the need for supports.