Here's a simple tool that I wish I had made years ago. These dividers are perfect for measuring short distances within difficult to reach areas like fuselages and the interior of any built-up structure like wings, and tails. It is far more accurate than a ruler or the dreaded method of laying the piece of wood across the structure and just cutting- a bad habit I finally broke with this tool. It's comprised of two pieces of 1/4" square bass wood, and cut T-pins inserted with pliers. The two legs are connected with a machine screw and washer. Harder wood and better hardware could be used if you like- just remember to pare down the tips of the legs where the pins mount for better accessibility. Do you have any unique tools that you've already built? Please share with the rest of the world and post a comment!