This is what Christopher tells us about how he and Nick build it:
For the pivot we used a 1/4 in diameter bolt with threads all the way up and put nuts on each side of the supports and each side of the throwing arm to keep it centered. For the power cord we cut the hooks off of a 48 inch black bungee cord and tied knots on each end as needed for power. We wrapped duct tape around the wood that the throw arm stops against for padding. After pre-drilling all the holes, we used 1 1/4 in. deck screws to assemble all the pieces. Before bringing the catapult in to class Nick wants to paint both the catapult and the base.
And a little bit more:
Hi Will, My son and I just built a catapult for his 8th grade science class. The requirement was to throw a tennis ball 30 feet. My son came up with the design and after a quick trip to Home Depot and about 2 hours in the garage building we finished the project. We tested and found it will throw a tennis ball 45 feet on the fly. The base plywood is the sink cutout from our kitchen granite counter remodel last year and the cup is from my wife's laundry detergent jug. My son Nick and I both enjoyed your web site. Thanks!
Nick and his dad have re-designed this catapult and built an even more powerful one that launches a projectile 60 feet! You can check out that catapult here
New Project: How to make a Mouse trap Catapult in about 1 minute. You don't need much and this thing is really powerful. You can probably fire small projectiles about 40 feet. How to make a Mouse Trap catapult
Mini Weapons of Mass Destruction: Build Implements of Spitball Warfare
PopularMechanics.com selection for one of The Best DIY and Home Improvement Books of 2009
We’ve come a long way from the Peashooter Era: with the advent of modern household products and office supplies—binder clips, clothespins, rubber bands, ballpoint pens, toothpicks, paper clips, plastic utensils, and (of course) matches and barbeque lighters—troublemakers of all stripes have the components needed to build an impressive, if somewhat miniaturized, arsenal.
Toy designer John Austin provides detailed, step-by-step instructions for each project, including materials and ammo lists, clear diagrams, and construction tips, for mayhem-loving MacGyvers. The 35 devices include catapults, slingshots, minibombs, darts, and combustion shooters. Build a tiny trebuchet from paper clips and a D-cell battery. Wrap a penny in a string of paper caps to create a surprisingly impressive “bomb.” Several of the projects even include variations where combatants mount laser pointer sights to their shooters to increase their accuracy.
Finally, once you’ve built your armory, the author provides plans for a Top Secret Concealing Book to hide your stash, as well as targets for shooting practice. Never let your personal space go undefended again!
Whoosh Boom Splat: The Garage Warrior's Guide to Building Projectile Shooters
The Art of the Catapult: Build Greek Ballistae, Roman Onagers, English Trebuchets, and More Ancient Artillery - Nice book that shows you how to build ten different catapult projects, moderate wood working and pvc piping kind of stuff. Good book with complete instructions and materials lists.
Backyard Ballistics: Build Potato Cannons, Paper Match Rockets, Cincinnati Fire Kites, Tennis Ball Mortars, and More Dynamite Devices Want to get a little more creative? This book is off the hook!
Working Wood Catapult Diy Kit, 6" X 5" X 10"
Expand your kingdom one cubicle at a time with this working replica of one of the most infamous and powerful siege engines... the catapult. When completed, the catapult can shoot a ball of soft clay more than 15 feet! Lay seige to your entire department with this formidable weapon and mercilessly crush cubicle uprisings. Includes all needed parts and soft modeling clay for projectiles. Requires knife and wood or white glue for assembly
Do you like making projects and exploring a variety of hobbies?
Sign up for my free newsletter. I give you regular updates on hobbies and projects you can make. it is totally free and I don't share your email with anybody.