How to Make a Medieval Trebuchet Out of Cardboard

Step 6 Drilling the Holes

There are six holes that need to be drilled in order to complete the throwing mechanism.

Two of the holes need to be drilled on the "arm" of the Trebuchet (Part B). The first hole should be 2-3 inches away from the wider end. I used a 13/16 inch drill bit to make this hole. Using the same drill bit, drill another hole approximately 10 inches from the wider side. It'll take some force, and maybe a couple pounds from a hammer, but shove a piece of 3/4 inch PVC pipe into each of the holes. Pre-cut these pieces of PVC so that they are flush with the cardboard on either side. See first picture for clarity

Drill 5/8 inch holes 2-3 inches from the narrow end of Part C. See second picture for clarity.

Drill 5/8 inch holes into the top of the counterweight and glue the washers around the holes. See third and fourth picture for clarity.

Now cut your 3/4 inch axle into a six inch piece and a 15 inch piece. Take the six inch piece and slide it through one side of the counterweight, then through the "arm" of the trebuchet (in the hole closest to the edge), and through the other side of the counterweight. Take your 15 inch piece and slide it through Part C. Slide the rest of the rod through the other hole in the "arm" and then through the hole on the other half of Part C. See fifth picture for clarity.