Building a book-shaped box with a living-hinge spine

Difficulty: easy. Time: 15 minutes design, 40 minutes making. Best method: laser-cut plywood.

A flexbook looks like a hardback book but opens to a hidden tray. The cover is one flat strip cut in three zones: a back cover, a flexible spine full of living-hinge slits, and a front cover. A shallow finger-jointed tray glues inside the back cover to hold whatever you want to keep. The Assembled 3D tab shows the covers and tray in place so you can judge size before spending a sheet.

Open the Flexbook 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 3 mm.
3D printing: any rigid filament. The flat covers and tray panels print without supports.
Glue: PVA wood glue for plywood, plus a couple of clamps or elastic bands

Step 1 - Cover size

Cover width and Cover height set the size of each book face. The flat cover strip is cut as one piece: two covers with the spine between them, so its total width is two covers plus the spine.

Step 2 - Spine and material

Spine width sets how thick the book is; the living hinge fills this zone so the cover folds around the tray.
Thickness must match your sheet, because the tray finger joints are derived from it.
Spine slit spacing tunes the living hinge: closer slits bend more easily but leave a weaker spine.

Step 3 - Check the assembly

Switch to the Assembled 3D tab and orbit the flexbook to confirm the tray fits between the covers. The Export Preview tab shows the flat sheet with the cover strip and each tray panel 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 score the fold lines before the cover outline so the strip does not shift once it is free.
Run a hinge test first on a scrap: cut a short section of the spine and check it bends without snapping before committing the full strip.

Glue up

Dry fit the tray finger joints first; charred ply needs a light sanding on the tabs, not force.
Glue the four tray walls into a ring, check for square, then drop the floor in and clamp.
Fold the cover along the two score lines, glue the tray onto the inside of the back cover, and let it cure closed.

Make It Yours

Engrave a title or name on the front cover before cutting so it reads like a real book.
Line the tray with felt to protect jewellery or medals.
Add a magnet recess to the front cover and tray edge so the book snaps shut.

Open the Flexbook Generator

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