Split Ring Planetary Gear High Torque

Can you please say how much torque you were able to achieve for the NEMA 23 ? Theoretically, assuming NEMA has 2.5 Nm torque capacity and the efficiency of two stages of gearbox is 60%, it would be 200+, but would it atleast able to hold till 100+ Nm? if you haven't tested yet, what is your guess?

Although it may break due to stress before getting to that level of torque

cool design, I've actually make a very similar gearbox myself although i've got more access to a machine shop so was able to make my gears out of metal. I'd be interested to see where you've found your sources for how to design each stage. The gearbox I've made has two separate sets of planets (could be 3D printed as one piece) and each set has the same number of teeth but a different pitch diameter, this does mean that each half of the reduction stage has a different module. per my understanding of these gearboxes i would think that your version would be the same as a regular planetary reduction with a single stage. Of course a good way to tell is just to test it! would be great to see a video with motor turning 258.4 times and see if the output rotates a full 360 degrees. Also id highly recommend looking into embedded nuts for your 3D printed parts if you haven't already.