My son heard that there were bad guys who were going to hold up our train on the Grand Canyon Railway and he wanted to make some handcuffs to arrest them. I found this project on Youtube that made them out of cardboard.  I used the file to cut some 3mm basswood plywood and it worked. 
Instructions: https://www.youtube.com/watch?v=RPjzT-p3v7s
Files from creator: https://drive.google.com/drive/folders/1pOdMZZg8cDKXCUVSDQjSWpbs8HfL9KkN