With the warmer weather right around the corner (75F and working its way up to 115F at a peak) I wanted a fidget that would keep me comfortable and a bit cooler. Spin and waft or hold angled to feel the air flow as the fan displaces best at an angle of 45-60 degrees. This would also can be used for student to learn about physics such as: fluid and gas flow, rotating bodies (as the fan spins it is harder to move it), and many other applications.
I used 1/4-20 standard hex nuts as weights and skateboard bearings for the rotation.
I printed this a 0.1mm layer height to ensure a nice fan blade surface. The structure is fairly minimal so little to no internal structure is needed, it's nearly solid with 2-3 perimeter shells on a 0.4mm nozzle printer.
The source files from solidworks are available
Manufacturing inconsistencies from the finishing process of nuts and the slight variations in print dimensions lead to some tolerance issues on rotational copied features. These usually cannot be compensated for with just an XY printing adjustment as you will have too small, too large, and just right (the Goldilocks flaw) all in the same print.
1.The nuts are loose: a few drops of super glue and using the hex caps will keep them secure (a few drops will usually hold the nut and the cap on once cured).
2.The nuts are too tight have several options, these are my three suggestions: A. file or sand the space larger; B. heat nut in 60C (hot)-100C (boiling) water and press the nut into the space; C. force the nut in with pressure and hope it doesn't crack the frame.