How to make a flat cardboard wind-up key for a doll costume
Trace two circles with a bowl, rule a straight shaft, and cut the key from one sheet of corrugated cardboard.
What You'll Need
- Large corrugated cardboard box
- Strong tape or safety pins
- Bowl or wide glass to trace around
- Marker or pen
- Metal ruler
- Craft knife or box cutter
- Cutting mat
The key in the photos is left as plain cardboard. Paint it gold or silver if you want, and let it dry before you attach it.
This wind-up key is one flat piece of corrugated cardboard: two round loops and a straight shaft. You trace the loops around a bowl, rule the shaft with a ruler, then cut it out. There is no gluing.
An adult does the knife cutting, on a mat, with the blade moving away from the body.
See what you'll make
This is the finished key, shown at the back of a dark top. It is one flat piece of cardboard: two round loops, each with a round hole in the middle, joined to a straight shaft. The next five photos show how to draw it.
Set out the cardboard, bowl and pen
Lay the cardboard flat and put the bowl and a pen on it. The bowl sets the size of the loops, so pick one about as wide as you want each loop to be.
Trace the first circle
Set the bowl on the cardboard and draw around its rim with the pen. Lift the bowl off. That circle is the first loop.
Trace the second circle
Move the bowl over and trace a second circle beside the first, leaving a small gap between them. The two circles are the loops of the key.
Trace both circles with the same bowl so the two loops come out the same size.
Join the circles with a curve
Lay the ruler across both circles and make a small mark at the middle of the gap. Draw a curved line from one circle to the other, just below that mark. This curve is the edge where the two loops meet.
Rule the shaft
Rule a straight line from the middle of the curve, down through the gap and past the bottom of the circles. Set the ruler next to it and rule a second line parallel to the first. These two lines are the sides of the shaft. Make the shaft as long as you want the key to stick out from the costume.
Close the end of the shaft with a short line across it. Cut along the outline with the craft knife on the cutting mat, then cut a round hole out of the middle of each loop, like the finished key in step 1. Fix the end of the shaft to the center back of the costume with strong tape or safety pins so the key sticks out. Check that it stays put when you move before you wear it out.
