A while back I asked if anyone had found a plugin for Rhino that would design a set of gears. I couldn’t find a plugin, but I did look at several stand alone packages that designed a working set of gears that could be saved as dxf files and then imported into Rhino. I found four with some promise.
Gearotic. $120 Very robust. Steep learning curve. Trial available
Involute Gear Builder. Online only. Free. Very Basic
Gear Generator Online version. Many options
Gear Template Generator $26. Good tutorials and YouTube Channel
My preference is Gear Template Generator. Priced right, easy to use, good docs.
Hope this helps