Alright bit of an update: Definitely strong enough, but be aware that the screws can come loose so either locktite them or check them every so often.
Couldnt really find any 2020 spool holders to go with the Parametric Universal Spool holder by rowokii (http://www.thingiverse.com/thing:767317) so I made one up for my Tronxy x3 quickly. I printed it but haven't tested long term strength. The arm is 150mm long and forms (about) a 75 degree angle w.r.t. the x-axis, so if you want to calculate the force on it you can certainly do that. I will say it feels solid and I doubt it will break.
There are two versions. Counter bored mounting holes and non. Unnecessary maybe but the option is there. basically its the difference of 5mm of plastic vs 3mm holding the thing on. I made the counter bore version to use extra 4x8mm screws from my kit, but the non version "should" be stronger.
Designed to be printed with minimal support and maximum bed adherence.
Any questions or comments let me know, if it worked for you let me know, if not I'm glad to hear how it could be better. This is my first design im releasing and I've only been using fusion for a few weeks, so I am always open to suggestion!
Additional Parts need:
Any spool holder that uses a 5/8" threaded rod.
4x 4mm (choose your length accordingly but probably between 8-15mm length should work depending on version)
4x 4mm t-nut
P.S. probably obvious but make sure you lay it flat lol.
Infill could probably be lower, just wanted to make sure the part was strong, resolution could be lower or higher. Printed on glass with gluestick. Cubic or tetrahedral in cura. I printed with supports for the holes.