Follow the official blog post:
First 3D print enclosed files. We printed those from Prusament PLA galaxy black. But if you will be placing the windmill outside, go for PET or ABS, the PLA does not resist high temperatures, especially when it is black – it absorbs almost all of the sun rays energy. You will need 12× blades, 1× base, 1× shaft parts, 1× tail & tail grip, clips (1× A; 6× B; 5× C) and 1× nose (only this one needs supports the rest in printable without supports. There is no special printing setting needed, just go with the default settings.
When printed parts are ready, let’s start assembling. Take one spool frontage and push it onto the base and insert the smooth rod. On the opposite end of the rod place the joint and slide perpendicularly the second smooth rod in.
Insert nuts into the holes and secure the rod with screws. Take the tail and slide it into the tail grip, secure it with screws and install it on the longer end of the horizontal rod. Secure the whole tail as well. Take the second spool frontage and prepare the clips. Click the clips to the spool as shown in the picture and insert the blades in. Use a super glue if needed. The last thing to do is to assemble the shaft. Important is to secure the 3D printed ring between the gears – it will protect the wheel to slid off. And do not forget to use the screws with the flat head for securing it, as it needs to rotate freely inside the shaft cover.
The windmill is ready! A potential linking it with a motor via a belt, turning it into a ventilator, is only up to you!