Here's a book with 12 different whirligig projects with a lot of good general information on making moving things from wood and metal.
Over 50 color photos, 80 patterns and mechanical drawings, with clear, concise, step-by-step instructions, reveal all the reader must know to successfully create twelve original whirligig projects made from wood and/or metal, including imaginative, original designs that all will enjoy. Each project has been designed, built, and tested by the author to ensure success. The detailed text provides tips for simplifying layout and construction techniques, the proper use of bearings and balance to spin whirligigs in minimal wind, along with practical woodworking, metalworking, and decorating techniques.
Here's a link to the book The Art And Craft of Whirligig Construction.