This is a shrunk down version of the one I  posted a few years back. See photo to get an idea  of size. Something equivalent to it is available from Lovejoy and another similar one is sold by McMaster but they are huge, expensive and entirely made of steel. My device can transmit power from one shaft to another at any angle between zero and 90 degrees. Shaft diameters are 5mm and all fasteners are M2 x 8 or 10mm (but you can use M3 in a pinch) socket flat head screws and nuts. Two bushings need to be pressed into the flanges for smooth running. I used PLA for all printed parts but anything rigid ought to work fine. 5mm shafts are a press fit in the gears but if you like you can tap the through holes for M2 setscrews. I will try to have finished examples on display at Bay Area Maker Faire.

Printing:

Print all parts in the orientation they appear. Print two flanges. Use 100% fill and no support is needed.

Sources:

All parts can be had from Amazon. If you prefer you can substitute plastic bushings for the oilite ones; just make sure they're 5mm id and 7mm od  and they should fit fine. I used 5mm steel shaft but brass works fine too. Just remember that if the assembly will be used someplace wet it would be best to use stainless fasteners and shafting.

Assembly:

Press a 5mm shaft into each of the gears so that the inner ends are flush with the inner surface of the gears.

Press a 5mm id x 7mm od x 8mm long oilite bushing into each flange making sure they don't stick out the large side of the flanges.

Push the M2 socket flat head screws through the case halves and attach a flange to each one using M2 hex nuts.

Now  slide the female gear shaft into Inner_Case_06 so the gear bottoms out in the case and the shaft sticks through the flange bushing.

Slide the male gear shaft into Outer_Case_04 in a similar manner

Carefully snap the case halves together and you're done.

PS let me know if you come up with any novel applications! :-)

PPS remember I'm broke and Patrons get access  to the .dx files and other perks! 

 https://www.patreon.com/Steamboat_Ed