Harry Potter style Time Turner. You have the option of printing an immobile design in one piece or two. You can also print a mobile design. This was originally intended to be an ornament and so is only about 20mm across. It scales well to 200%. You may not get an intact print at 100% scale (see print settings). Most of the samples were printed using the rings without flanges. I added flanged rings but have only printed them using the mobile "print in place design"
I printed with a variety of filaments including petg, PLA, polysmooth, colorfab copper.
I use Simplify 3d to slice and I couldn't get it to fill the rings at 100% scale. This probably has to do with my nozzle dimeter of 0.4mm and extrusion width but I'm not sure. It would fill in at 110% scale. So the smallest items pictured are 110% scaled. I scaled all my mobile prints at 200% with modification for the hour glass and pins as below.
I used 100% infill on all prints scaled at 110%. I used 30% infill on larger single piece designs and the star piece for the mobile design. I used 100% infill for the rings and pins for the mobile design.
For designs with a separate hour glass, I printed in vase mode using a clear PETG for one and Polysmooth clear for another. For one piece designs, I printed using the same clear materials and then painted. For 200% scale prints, I printed the hour glass at 197% scale to provide a snug fit. I used an attached 10 shell skirt. If you print in vase mode, the hour glass will be fragile and you will have to carefully adjust your temperature and extrusion multipliers to get the best adhesion. You can see a few failed hour glasses in my picture.
These are tiny. I used rafts and supports at 100% infill. Consider scaling to 195% in the cross section to facilitate fit. Scale the long axis to that of your base design.
If you print a non-mobile one piece design, printing in a clear material and then painting makes for a nice look. The gold painted large sample is a one piece made from petg. For two piece designs you can use a clear material for the hour glass and your preferred color for the body and rings.
Print the hour glass clear and the rings and stars in your preferred material. I'd suggest using a drill bit to regularize the holes in the rings and the stars. You may have to sand the pin slightly.
I used cyanoacrylate glue sparingly in the pin holes on the stars. You can do one side and then the other. The hour glass can be placed and then have a small amount of CA glue to hold it in place.
Print in place
I created a mobile design with flange and pins attached to the stars. This version printed well using 0.2 mm layer height. This may be the easiest to print if you do not want to mix and match material colors as it avoids gluing the pins.