# Box joint (finger joint)

> How wide are the fingers in a box joint?

- Category: Joinery › Edge & case joints
- Kind: Hardware
- Basis: Xem Studio design — geometry computed in the generator from traditional proportions
- Page: https://xemstudio.com/objects/box-joint/ · JSON: https://xemstudio.com/api/geometry?object=box-joint · Plain text: https://xemstudio.com/objects/box-joint/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files Xem Studio Design License (free to use and sell from, not to redistribute as files: https://xemstudio.com/license/)
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

## Overall (mm)

| length | width | height |
|---|---|---|
| 90.0 | 60.0 | 90.0 |

**Exact dimensions.** True size, with no printing tolerance added.

## Notes

- Woodworking joint drawn for 3D printing: the parts lock together by shape, so a print can be joined without glue or screws. Drawn at true size with the parts line to line (zero gap) in their assembled position — add your printer's fit allowance to the mating faces (your AI or slicer can do this).
- Square interlocking fingers, each as wide as the board is thick. Simple, strong, prints cleanly flat.

## Sizes

| dimension | value |
|---|---|
| stock | 10 mm boards, 60 mm wide |
| parts | board a, board b |
| fingers | 10 mm wide, 10 mm long (one board thickness), 6 in all |
| assembles | one board drops onto the other |
| holds | racking, with a large glue area; pin it or glue it against pulling apart |

## Where the files are

- Xem Studio: [Joinery design (geometry computed in the generator from traditional proportions)](https://xemstudio.com/) — web — Xem Studio design

## Free STEP/STL (3 parts, Xem Studio Design License, Xem Studio)

Index: https://xemstudio.com/files/hardware/box-joint/index.json · license: https://xemstudio.com/files/hardware/box-joint/LICENSE.md

- box-joint-board-a: [STEP](https://xemstudio.com/files/hardware/box-joint/box-joint-board-a.step) · [STL](https://xemstudio.com/files/hardware/box-joint/box-joint-board-a.stl) — Board A: three fingers
- box-joint-board-b: [STEP](https://xemstudio.com/files/hardware/box-joint/box-joint-board-b.step) · [STL](https://xemstudio.com/files/hardware/box-joint/box-joint-board-b.stl) — Board B: three fingers, offset by one
- box-joint-assembled: [STEP](https://xemstudio.com/files/hardware/box-joint/box-joint-assembled.step) · [STL](https://xemstudio.com/files/hardware/box-joint/box-joint-assembled.stl) — All parts in their assembled position (each part its own solid)

## Questions

**How wide should box joint fingers be?**

Usually equal to the board thickness: 10 mm here.

## Fits with

- [Through dovetail joint](https://xemstudio.com/objects/through-dovetail-joint/)
- [Finger splice joint (finger joint for lengthening)](https://xemstudio.com/objects/finger-splice-joint/)