As a fabricator, I’m constantly looking online for input, ideas or even working plans for my self-sufficient living projects. One of the best sources of information I’ve found are the various patent sites.
The other day I downloaded a patent for an efficient wood heater. The drawings were detailed enough to actually build a unit from. For an upcoming home-built vertical axis wind generator I’ve assembled enough information, from airfoils to generator to structure, all from patents available online.
Of course you aren’t allowed to go into production of the “invention” but for the purposes of building your own equipment for self-sufficient living it is quite OK to base your design on patents.
The easiest site I’ve found is freepatentsonline. All you need to do is register and images, drawings and the full patent is made available in PDF which you can easily save to your computer.
The search function at freepatentsonline is a little whacky. If I can’t find what I want I’ll often just use Google for the same search terms and add the word freepatentsonline. Google’s results are often better. Having got some results, be sure to see related patents or “patents that cite this patent”. There is a goldmine of information available.