I decided to develop gearbox with ratio from 1:25 to 1:35 to archive 180 degrees per second with full torque (i hope).
Small backlash is acceptable (at least for robot leg actuator)
All designs will be created in Openscad.
I had a few experiments in the past: So my favorite designs are:
1) Spur Pinion double gears organized in 3 gears per stage (each stage is a 3 spur-pinion gears at triangle corners) with ring gear as output: Openscad drawings and visualization will be uploaded soon.
This type of gearbox have 1:33 ratio (can vary, but not limited at max)
2) Cycloidal - i experimented in past, I got 1:25 ratio (strong limit for 70x70 cm footprint), but my past experiments had some Issues (mostly because of missing bearing at critical places)