How to Build a Trebuchet

If you want to get a firsthand experience of what it was like to be in a war in ancient times, making a trebuchet is a perfect fit. A trebuchet was used as a siege device to throw boulders and stones at the enemy’s domain and castle as a way to break entry. These instructions give you the opportunity to make a miniature trebuchet of your own.

Tools required

  • Pencil
  • Sandpaper
  • Pliers
  • Saw

Materials required

  • Plywood
  • Cardboard
  • Wood glue
  • Hooks
  • Nails and screws
  • Metal rod
  • Tape
  • Plastic
  • Yarn
  • Projectile
  • Stones


  1. Have a basic plan to designate the measurements of the trebuchet. Take a piece of wood and cut it into eight different pieces with the saw. Cut the pieces so that you have a very tall one, a pair that is a few inches shorter, then another pair that is shorter than that, and then the next three should be similar.
  2. Make a wooden triangle by cutting a square wooden piece and connecting them diagonally. This should produce two triangles of the same size then make a line from one point to the opposite diagonal point before cutting the wood. These pieces would be the side of the trebuchet.
  3. Take two pairs of wooden pieces, one longer than the next, and connect them to ¾ of the length of the longer piece of wood (You should have two of these). Then tie a triangular wooden piece to one of the attachments made in the last step. Glue the triangle so that the slanting side is toward the longer side of the base
  4. Using the other triangle and connect it to the second side. Use the two pieces from the remaining 3 small pieces. Then nail and glue all the wood pieces together.
  5. Mark the location of holes in the upright arms with a pencil leaving an inch at the top. There is where the axle will go. Use the pencil to mark the location of holes in the upright arms at least an inch from the top. This is where the axle will go.
  6. Start making the swinging arm which consists of the axle with a piece of metal that carries a counterweight. The distance between the two upright arms of the base should be the length of the axel and then drill holes in the upright arms large enough to allow the axel to move.
  7. Mark three holes on the longest piece of wood for the swinging arm of the trebuchet. The first hole should be a quarter of the length of the total length away from the edge. The other two should be 1 – 2 inches apart from the first hole.
  8. Drill the marked holes in the swinging arm and insert the axel in one of the holes and swing the wood around it. Fix a hoop hook at the edge near the drilled holes and then place the counterweight on it.
  9. Nail on the opposite side with a hammer then cut the head. Bend it slightly so a loop can’t stay there until released. Then fix another hoop hook away from the nail towards one side of the wooden piece on the same side of the swinging arm. This is the end where the projectile will be installed.
  10. Insert the axle through an upright arm of the base into one of the holes drilled in the swinging arm and through the other upright arm. Make sure the hoop hook fixed on one side of the edge faces down. Swing the arm to test it to see that it is working.
  11. Collect materials such as molding clay, or small stones then wrap the collected materials in plastic and tape them to make a counterweight the size of a golf ball. Use thick yarn or twist ties to hang the counterweight from the hoop hook fixed at one end of the swinging arm.
  12. Cut two lengths of yarn about 20 inches long, then take a rectangular piece of fabric and tie one end with one yarn length and the second end with another piece of yarn. The middle part of the fabric can hold the projectile.
  13. Twist a piece of thin metal wire into a small loop. Secure the loop to one of the free ends of the yarn with which the sling is tied. Tie the other free end of the yarn to the hoop hook fixed on the far side of the swinging arm.
  14. Slide the thin metal wire loop over the nail. The slight bend in the nail will help keep the loop in place. Provide cleared space from where the sling can slide off by fitting a piece of cardboard or plywood on the inside of the base.
  15. Pull the edge of the swinging arm down to where the sling is attached then draw down the sling onto the base as far as it will go. Then the sling is placed toward the counterweight. Load the projectile into the sling and release the swinging arm to launch the trebuchet.

Tips and Warning

  • If you wish you can try to make a bigger model of the trebuchet if you have a larger space to use it.
  • Don’t file down all the pieces of cut metal because this could cause harm.
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