This is my second ratchet design iteration. The previous ones required some assembly and M3 nut & bolt but in this one the single STL file contains both parts preassembled so you don't need to join them after the print.
I left 0.3 mm gaps between the parts and printed from PLA with 0.2 mm layer height, without any support. The result is so fantastic I'll continue use this pre-assembled methodology in my future designs!
I printed it on my Prusa i3 MK2 which did not get the multi-extruder upgrade yet but to bow before the father of my wonderful printer I rendered an image where the lock mechanism is Prusa-orange :)
Update #20170308: I have added a 40 mm version to the models for thicker cables.
Update #20171202: I have added an iteration with less teeth.