2 2 in × 4 in (5. 1 cm × 10. 2 cm) wood pieces, 36 inches (91 cm) long 2 2 in × 4 in (5. 1 cm × 10. 2 cm) wood pieces, 12 inches (30 cm) long 2 2 in × 4 in (5. 1 cm × 10. 2 cm) wood pieces, 23 inches (58 cm) long 1⁄4 inch (0. 64 cm)plywood that is between 20–24 inches (51–61 cm) square 1 piece of flat wood (can be plywood) that is 10–12 inches (25–30 cm) wide and 36 inches (91 cm)long to serve as baseboard 1 inch (2. 5 cm) diameter dowel rod, 15 inches (38 cm) long 2 eye hooks
If you don’t have a table saw or jigsaw, many home improvement stores will cut wood for you before you take it home.
Lay one of the triangle-shaped pieces on top of these supports so that the base of the triangle is aligned horizontally with the bottom of the 36 in (91 cm) piece of wood. Attach 1 screw to each corner and 2-3 screws along each side of the triangle.
When both sides are constructed, line them up and make sure they are identical mirror images of each other.
At this point, the base is almost finished. You should have a rectangular base with 2 vertical supports.
You don’t want the hole to be too large because you want the dowel rod to be secure.
Screw 2 eye hooks into the front end of the trebuchet baseboard about 8 inches (20 cm) apart.
Hammer 2 in × 4 in (5. 1 cm × 10. 2 cm) piece of wood, 40 inches (100 cm) long 5 feet (1. 5 m) of string 10 in × 6 in (25 cm × 15 cm) piece of cloth to make a pouch 2 eye hooks 1 long thin nail with the head removed
Test the rotation by putting the rod through the 2 in × 4 in (5. 1 cm × 10. 2 cm) piece of wood. If the 2 in × 4 in (5. 1 cm × 10. 2 cm) piece of wood rotates without resistance, the hole is large enough. The end closest to the hold is the back end of the swing arm.
Hammer the first eye hook into the end until just the loop of the hook is sticking out.
Hammer the nail into the flat end of the swing arm, approximately in the middle. Bend it slightly forward so that the string will stay on until the trebuchet is launched. The angle of the bend will need to be optimized using trial and error launches.
You want the bucket to hang vertically down but still be close to the arm. Tie it so that it hangs about 1–2 inches (2. 5–5. 1 cm) from the top of the arm. Fill the bucket with rocks or heavy pieces of metal. Alternatively, you can attach a heavy weight such as a 20 pounds (9. 1 kg) hand weight directly to the end of the arm.
Tie a 27 in (69 cm) piece of string to one end of the pouch and make a small loop at the other end of the string. Hook the loop on the nail at the end of the arm. This piece is longer to account for the loop. Tie a 24 in (61 cm) piece of string to the other end of the pouch. Tie the other end of the string to the second eye hook (the one still sticking out of the wood). The pouch should hang evenly off the back end of the arm when you are done.
The coat hanger must be made of wire so you can manipulate it for the trigger. If you don’t have wire cutters, find another tool that will cut through the hanger. You can use as much or as little string as you like for the trigger.
Again, make sure the swing arm can rotate freely around the dowel rod.
Pulling the string releases the swing arm and launches whatever is in the pouch.
You want both sets of strings to be approximately the same length and for the pouch to sit close to the end of the baseboard.
Alter the angle of the nail as needed to get the best launch distance. Trial and error is the best way to accomplish this. Adding heavier items to the counterweight will allow you launch heavier things and/or launch things a further distance. Don’t stand in front of the throwing arm when releasing. It might hit you in the face and cause injury. In early tests, the throwing can be unpredictable; stay clear of all moving parts.
