When I printed the original Filament Spool Switcher & Winder, I had two problems with the axis:
So I decided to redesign the axis and made them in a hexagon profile. They are easy to print, no support needed. The axis with the worm drive is now one 128mm long axis instead of two short ones.
Because every Filament and every printer is different, it's hard to find the right tolerances between the axis and the gear, especially when you use different materials for the axis and the gears. So I published the axis with slightly different diameters.
You should start with 8,1mm, this should work fine in most cases. If it's too tight to get the gear on the axis, try 8,0mm. If it's too loose, try 8,2mm. If all of this does not work, you can play with parameters like flow, wall thickness or slightly resize the axis in you slicer. Or use a drop of superglue if it's too loose.
Assembly:
The Assembly is nearly the same as with the original parts. At the 128mm and the 47mm Axis are little stop-marker.
The marker at the 128mm axis is to find the right position for the worm drive. The worm drive has to be right from the marker (if you look from the front of the winder).
The marker at the 47mm axis is just a kind of spacer to keep the handle or the drill adapter away from the bearing.
The author remixed this model.