Introduction: 2 X 4 Catapult

We’re kicking it old school with one of the first times people made things that fly a catapult. Although they made objects fly at each other. This catapult is built out of 2x4s and is tensioned by a torsion bundle.



1” wood rod

Wood Screws


Step 1: Cuting the Wood

Use a saw to cut out of the 2 2x4s these lengths.

Cut Lengths:

  • 2 x 24" (base pieces)
  • 5 x 12” (base pieces / tower pieces)
  • 2 x 8 1/2” (angled supports)
  • 2 x 16 (angled supports)
  • 20” x 1 (catapult arm)

Step 2: Building the Base

Screw the 24" parts to 2 of the 12" parts standing on the thinner side so the ends of the 12" parts are sandwiched by the 24" parts. This should create a 24" x 16" box.

Step 3: Building the Frame

Screw in 2 12" parts on the base standing up straight 14" away from the back. Then screw in the last 12" part in-between the parts you just put on the bridge the top.

Step 4: Attaching the Angled Supports

It's time to bust out the saw again and cut 45° angles on the 8 1/2" parts and 16" parts. Then screw the 8 1/2" on to the front of the frame like show in the picture.

Step 5: Drill a Hole in the Arm

Drill a hole in the arm of the catapult through the side 1" from the end and big enough to put your rope through a couple times.

Step 6: Drill Holes in the Sides

Drill holes under the frame for the rope. The holes should be big enough to put the rope through multiple times.

Step 7: Wrap the Torsion Bundle

You'll need 2 handles so cut the 1" rod so you have around 10" long handles. This step is a little complicated so I'm outsourcing it to this video of some Welsh man explaining how to do it. It should look some thing like this.

Step 8: Attaching the Angled Supports Part:2

Now that you have wrapped the torsion bundle you can screw in the 16" angled supports.

Step 9: Tighten the Bundle

Turn the handles towards the front of the catapult tightening the arm. You may want something like a PVC pipe to put over the handles to get more leverage. Then when they are as tight as you like put screws in to hold the handles in place.

Step 10: Finishing the Arm

Attach something to the end of the arm to hold your projectile. I used a small metal bowl but you can use anything you want. And I also tied on a small piece of rope to pull down the arm.

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