The gear ratio of two of these in series is 1,901,641 : 1
Please know that this gearbox is designed to be a simple demonstration model. it will self destruct under load, please watch the end of the youtube video to see the failure mode.
Gear Down For What?
1,379 Turns of the input sun gear will result in ring gear #2 making one full rotation.
These are designed to be able to mount them in series on the channel, or drive them with the included stepper motor mount. You will need to scale the channel longer if you want to use two gearboxes and the stepper motor mount on the same channel, but keep in mind it is very boring to watch the second gearbox rotate, as it is very slow.
Helix angle 30deg
Pressure Angle 20deg
Planetary Gearset #1 (Input End) Tooth Module = 1
Sun = 16T
Planets = 17T
Ring = 50T
Planetary Gearset #2 (Output End) Tooth Module = .846
Sun = 19T
Planets = 20T
Ring = 59T
I Also Included the Fusion 360 Project with this :)