Here is my first attempt at gears and proper alignment (not that I tried to follow the complete mathematical equation). The biggest take-away for me was that if you’re doubling the size of the gear, then you halve the size of the angle for the next tooth (or spur). If you’ve done it right, then you’ll have a perfect alignment and double the teeth on the larger gear. In my case, I have 18 teeth in my smaller gear, 36 teeth on the larger gear, and they are all spaced out evenly.

The dimension of the small gear is; 30mm diameter (excluding the teeth) and 8mm in height/thickness. There is a 16mm wide by 5mm deep hole for seating a bearing.

The larger gear’s dimension is; 60mm diameter (excluding the teeth) and 8mm in height/thickness. There is a 22mm wide by 7mm deep hole for seating a bearing.

The next step will be to 3D print the gears and test them out. Based on the filament used in SLA printing, there is a 7% shrinking rate, so I’ll have to account for that as well. Hopefully, the 3D printing software will allow for this adjustment.