Introduction: UTreb : the 1/8 Trebuchet

About: I'm a maker.

This amazing project was born few years ago for my grandpa'show named "Les Amis de Buxièxe". The subject of the show this year was the history of a medieval lord. And for one of the scene, my grandpa needed a real size trebuchet and without any knowledge about this kind of machine. So I make many research and found a little soft on which I spend hours to optimize the different lengths and to make the most efficient trebuchet possible.

After the first step of research, we design the plan in 3D and we create our trebuchet ! It was fantastic and seduced the public.

So we got a fully fonctionnal real size trebuchet, the plan and CNC in our little familial worshop. Our trenuchet was really difficult for the most of one but what about a kit version ? That what I did, a 1/8 version of the trebuchet that every one can make from a just a 10mm plank of wood.

Step 1: Preparation

Needed machine :

The only machine that you need is a CNC. If you don't have access to anyone, you also can use the DXF files provided, print it and make wooden pieces by hand.

Needed tools :

  • Sanding paper
  • Scissors

Needed material :

  • A 10 mm wooden plank like medium
  • Kitchen string
  • Leather or other fabric
  • 4 mm diameter rod brass

Step 2: Machining

You first need to make all the wooden part using a CNC machine. I provide you the DXF with all the part needed. The wood is really simple to machine. You only should a 3mm diameter flat drill.

Step 3: Other Parts


Print the PDF named Sling.pdf and cut in a small part of leather the sling with scissors.

Brass axes

You need to cut three 4mm diamteter brass axes with

  • 1 x 55 mm lenght
  • 1 x 80 mm lenght
  • 1 x 105 mm lenght

Step 4: Assembling

First, you need to take out the plank all the parts using a cutter if you make clip while machining.
Like our little friends, set the parts 1, 1 and 3.
Set now the parts 3 and 4. They are a little bit different, be careful to put the right in the right place.
Use wood glue and fix one of the parts 3 and 4.
Glue now the ladder (part 5)
Do the same thing with the other part (3 or 4) and with the other ladder (part 5).
Glue the x part number 6.
Now the little men will build the counter weight. You need the parts 7, 8, 8, 9 and 9.
Glue all the parts and use some elastics.
Wait for the glue to dry. Set the chute (part 10).

Fix the counter weight using the 55 mm brass rod to the part 11.

Fix the part 11 to the rest of the trebuchet using the 80 brass rod and four part 12.
Glue the axes
Put the 105 mm brass rod like our little friends.
Set and glue on the axe the parts 14 and 13.

Use a 4mm diameter screw to fix the part 16.

Fill the counter weight with sand
Fix the sling with rop and the part 16.
Finish ! You are ready to attack a castle !
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