Plans
Free plans for the 10 lb pumpkin trebuchet
The plans are a free PDF with no sign-up, and they cover the full-size machine from the 2023 build. Dimensioned drawings, a cut list, a parts list and safety notes come in one file.
[n] pages, [paper size]
What is in the PDF
- p. [n]
Dimensioned side and front elevations
Every member with its length and angle called out.
- p. [n]
Arm lamination schedule
How the arm is built up from layers of lumber.
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Axle and bearing detail
The pipe axle and how the arm pivots on it.
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Counterweight box
Box construction and how the plates load in.
- p. [n]
Sling and pouch pattern
The pouch pattern and the cord layout.
- p. [n]
Cut list
Every piece to cut, grouped by material.
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Parts list
Hardware and materials, matching the key parts below.
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Safety notes
Setup, clearance and test-throw practice.
Layout previews, dimensions shown as [dim]
Preview spreads
[dim]
[dim]
[dim]
Side elevation
SHEET 1 OF [n][dim]
[dim]
arm
sling and pouch
Arm and sling
SHEET 2 OF [n][dim]
[dim]
Detail A
Counterweight box
SHEET 3 OF [n]2023 machine
Measured results
These are the numbers behind the plans, and more will be added after the 2026 field day.
| Projectile | 8 to 10 lb pumpkin | measured |
| Counterweight | about 180 lb | estimated |
| Best range | not yet measured | unmeasured |
Text links, no prices
Key parts
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| Part | Why it matters | Where to buy |
|---|---|---|
| Pneumatic wheels and axle kit | Air-filled tires roll over rough pavement, and the base moves forward as the arm swings. | Amazon |
| Steel pipe for the axle | The arm pivots on it and it carries the full counterweight load, so it must not bend or bind. | Amazon |
| Eye hook and release pin | The hook holds the sling at the arm tip, and the pin lets go at the launch angle. | Amazon |
| Steel cable, thimbles and clamps | Joins the arm tip to the sling; thimbles keep the cable from kinking at each loop. | Amazon |
| Rope and sling cord | Sets the sling length and takes the sharpest shock of the throw, so replace worn cord. | Amazon |
| Weight plates | The counterweight itself; the box is loaded in steps and the amount is tuned between throws. | Amazon |
Plans
The plans are free.
Dimensioned drawings, a cut list and a parts list for the 2023 machine, as one PDF. No sign-up. If you buy the hardware through the links above, the site earns a small commission at no cost to you.
Questions
Questions
Which build are these plans for?
They are drawn from the 2023 machine, the full-size wheeled A-frame. Dimensions that were never measured are marked as such, and the 2026 build is meant to fill them in.
Can I scale it down?
Probably, but the arm, counterweight and sling work together, so the drawings will not shrink cleanly. Build a tabletop model first and test it before you cut lumber.
What tools do I need?
Ordinary workshop tools: a saw, a drill, clamps, a tape measure and wrenches, plus a way to sew the sling pouch. The PDF should call out any step that needs more than that.
Is it safe?
Not automatically; a trebuchet swings a heavy arm and throws heavy objects, so keep everyone clear of the arm and the landing area and start with light loads. The safety notes in the PDF cover the basics, and how you build and operate it is your responsibility.
Which build
Which build
The first wheeled machine
A smaller machine, and the first one built on wheels.
The full-size A-frame
The wheeled machine that throws 8 to 10 lb pumpkins. These plans describe this one.
Read the 2023 build logThe larger machine
Under construction in October 2026. Its plans follow once it is drawn and measured.
Only the 2023 plans are available now.