I got an old sewing machine at goodwill and steamed it up with brassy bits! The propellers spin when the drive wheel and thread move. See the whole flickr set. This was an assignment in my sculpture/metalworking class. What can I say, I have a totally superfluous understanding of the movement, with little of the patience and attention to detail indicative of steampunk. I did learn how to use a bead blaster, though.