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

> a book-shaped box with a living-hinge spine and hidden tray

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.

## What you 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.

## Laser cutting

### Before you cut



1. Measure your sheet with calipers and set **Thickness** to what you measured, not what the label says.
2. Cut the living-hinge slits and score the fold lines before the cover outline so the strip does not shift once it is free.
3. 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



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

## 3D Printing

### Slice and print



1. The 3D download is a zip with one part per panel plus a solid cover strip, numbered to match the flat sheet order.
2. Every part is already extruded to the **Thickness** value. Do not scale the parts in the slicer: it changes the joint sizes too.
3. Lay each panel flat on the bed. No supports are needed.
4. Print at 0.2 mm layers with 3 or more perimeters so the finger joints come out strong.

## 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.

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Open the Flexbook Generator: https://www.mylasertools.com//flexbook-generator
Read online: https://www.mylasertools.com//learn/guides/flexbook-generator