This is a small experiment I made to model and create gears with a sort of herringbone tooth shape. I modeled it in FreeCAD, using the Involute gear and Loft functions, and it came out quite nice.
Since it's also a nice object to see, and to play with, I decided to share it.
I used Simplify3D to slice it, putting both gears in one print, and the base and two caps in another (to print them in different colors).
The whole thing printed in about two hours.
I printed it using and Arduino Materia 101, in black and bronze 1.75mm PLA, with 0.2mm layers and 50% infill for sturdiness.
I suggest printing both gears in one go, and the base with 2 caps in another.
Once printed, hold gears in interlocked position (mind the direction of the teeth!) and slide them both into their axes.
Caps, if printed properly, should fit tightly over the axes and make a sort of "click" when pushed down, without need for glue.
In case the caps are too loose, put a tiny drop of glue inside the caps, on the flat inner surface, and push them into position.
Be careful not to have glue spilling down along the axes and blocking the gears.