I'm guessing you're getting about a 10:1 gear ratio since the drive gear on your motor looks to have +/- 11 teeth and I'd estimate that if the gear on the scope was a completely circle, it would have ~100+ teeth. In my case, I have a 6.5:1 ratio (20 teeth on the drive gear and 130 teeth on the scope side). And now I'm adding a stepper with a 5.13:1 gearbox.

I did some additional experiments with the geared stepper and discovered that the problems I was seeing with inconsistent (even backwards) movement went away when I increased the step delay in the WMH driver. I had been using a 40us delay per step, and am now using 100us. I'm guessing it was trying to micro step too quickly. I bet that's the issue I was getting on my regular stepper as well. I'll have to see if it performs better with the higher step delay. I also have the option of turning micro stepping off completely. The only reason it was used in the first place was to smooth out the motion and not to actually increase resolution. But if the stepper loses torque in the process, it might be better to just use the native step size of the motor. The gearing should improve both torque and resolution.

I had been looking for your original CAD files to adapt your gear design to my layout. However I can do that pretty readily in Fusion360 if I need to. I also probably have a Nema bracket around somewhere if I end up trying out your design. I'm still hopeful that I can get the belt driven solution to work.

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