Building a finger-jointed pirate treasure chest

Difficulty: medium. Time: 20 minutes design, 60 minutes making. Best method: laser-cut plywood.

A treasure chest is a box with a personality: a solid finger-jointed base and a curved barrel lid that clicks it from a plain crate into a pirate hoard. This generator cuts the finger joints for the base, then builds the lid from two half-disc end caps and a single flexible band scored with a living hinge so it wraps into a smooth half-cylinder. The Assembled 3D tab shows the dome sitting on the base so you can check the proportions before spending a sheet.

Open the Pirate Chest Generator

What You'll Need

Laser cutting: 3 to 6 mm plywood or MDF. Measure the actual sheet thickness with calipers, it is rarely exactly the labelled value.
3D printing: any rigid filament. The lid exports as a solid band and two end caps rather than a living hinge.
Glue: PVA wood glue for plywood, plus clamps or elastic bands to hold the curved band while it dries

Step 1 - Chest size

Width and Depth are the footprint, and Base height is the straight-walled part below the lid. The lid radius is half the depth, so a deeper chest gets a taller dome. Thickness must match your sheet because every finger joint is derived from it.

Step 2 - Tune the lid hinge

Hinge slit spacing sets how close the living-hinge cuts sit in the lid band.
Closer slits bend into a rounder dome but leave the band more fragile, so test on scrap first.
The band always wraps between the two half-disc end caps to form the barrel.

Step 3 - Check the assembly

Switch to the Assembled 3D tab and orbit the chest to see the barrel lid sitting on the base. The Export Preview tab shows the flat sheet with the base panels, the two end caps, and the hinged band each in its own colour.

Choose Your Build Method

Before you cut

Measure your sheet with calipers and set Thickness to what you measured, not what the label says.
Cut the living-hinge slits and finger joints in one pass, then the outlines, so the delicate band does not shift once it is free.
Run a bend test on the band offcut first: if it cracks, widen the slit spacing before committing the full lid.

Glue up

Assemble the base first: glue the four walls into a ring, drop in the floor, and check for square.
Gently flex the hinged band into a curve and glue its edges to the curved side of each end cap.
Hold the band with elastic bands or tape until the glue cures, then attach the lid to the base with a hinge or leave it as a lift-off top.