This is a remix of scottan's top mount spool holder for the Robo3D R1. I made a few usability enhancements for it.
First I changed the spool spindle so it slide in and out with ease. No tight fit problems and no hardware required (for the spindle at least).
Second, I added a bridge. The bridge adds stability to the holder and makes it feel very sturdy.
There are two versions of the bridge, my original (the "v3"), and a new one with a built in Oiler ("v4.1"). Either can be used (and you only need one of them). Both require 4 (four) heat set inserts (#10-32, .225" long) which can be found from McMaster-Carr (https://www.mcmaster.com/#93365a154/=15nkvll). You can find instructions on inserting these at Matterhackers (https://www.matterhackers.com/articles/fasteners-for-3d-printing). I personally prefer using an insertion tip specifically for the inserts instead of a standard soldering tip(https://www.mcmaster.com/#92160a127/=15nkx0d), but that is up to you.
In addition 4 (four) #10-32, 3/4" long flat head screws are needed to attaché the supports to the bridge. For the oiler version you will need a small piece of sponge to shove into the oiler cavity.
I have also included a bonus clip that I use to keep the cable guide for the print head out of the way. It's easy to install and it makes taking the cover on and off much faster.
Note that the offset support is "universal" (there isn't a left/right), so you will need to print 2 of them. :-)
25~50% (use 100% for the cable guide clip
I print using PLA. I prefer a 50% infill for anything that will take wear and tear, and that's what I used for my print. The cable guide clip needs 100% infill to be sturdy enough for wear and tear, and so the clip wont break accidentally.
To assemble, first insert the heat-set threaded inserts into the bridge you have printed. Once that is done, attach the bridge to one of the two supports and insert the support into the top of the Robo 3D printer. You can then insert the other support and attach it to the bridge with screws.