Ulitmaker (a 3D printer manufacturing company) published this article by our very own Mr. Morrill on their Education Resources board. It's about our fifth graders' and their design challenge to design their own real-world tool, inspired by a wrench printed by NASA in space. https://ultimaker.com/en/blog/52573-wrench-engineering
"I developed a design challenge for my fifth graders that asks them to design a real-world tool. I take several lengths of 2x4 wood, drill pilot holes, then screw lag screws of various sizes into the wood. Every student is assigned a screw, and they must engineer a custom wrench to get it out of the wood. We learn to use calipers to measure the distance between the flat sections of the screw heads."