Windmills not only add movement and visual interest to your garden, they also keep away pests. Birds and rodents don't like moving objects, so the turning blades of a windmill are terrifying to them. You can place your windmills under fruit trees and near trellised vines to keep these creatures away from your harvest. Plus, a swiftly turning windmill can warn you of coming storms.
Choose a diameter for your windmill. Small garden windmills should be no larger than about 18 inches wide and no smaller than about 10 inches wide.
Replace the chalk or pencil in your compass with a grease pencil. Adjust the compass to half your chosen windmill diameter. In this case, 9 inches is the proper measurement.
Draw a circle on your metal flashing. Cut out the circle with tin snips. Use a yardstick and your grease pencil to bisect the circle with one line, quarter it with another and divide each quarter into two equal pieces. You should end up with a circle divided into eighths.
Drill a hole through the centre of your circle with a ¼-inch-diameter drill bit. This marks the centre of your windmill blades.
Cut into each eighth-mark line, stopping about 3 inches from the centre hole. Lift each eighth section and twist it 45 degrees to the right. This puts the blades on an angle that the wind should be able to catch.
Slide a ½-inch washer onto your ¼-inch-diameter steel screw. Slip the screw through the centre hole in your windmill blades. Slip a second washer onto the end of the screw so that the windmill blades are sandwiched between two washers.
Screw the screw into your wooden garden stake, spacing it about 1 inch from the top. The washers and windmill blades should be snug against the stake but still able to turn freely. Drive the last 6 inches of the stake into the ground.
Create a "fancy" windmill by punching or cutting designs into the blades with a metal punch, awl or high-speed rotary tool. Decorate your garden stake with painted designs, river stones, braided ribbon coated with lacquer or wire. Create several windmills of different sizes to create a wind vignette in one corner of your garden.