# Hooked scarf joint (okkake tsugi)

> How does a hooked scarf joint resist pulling apart?

- Category: Joinery › Scarf & splice joints
- Kind: Hardware
- Basis: Xem Studio design — geometry computed in the generator from traditional proportions
- Page: https://xemstudio.com/objects/hooked-scarf-joint/ · JSON: https://xemstudio.com/api/geometry?object=hooked-scarf-joint · Plain text: https://xemstudio.com/objects/hooked-scarf-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 |
|---|---|---|
| 220.0 | 20.0 | 20.0 |

**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).
- A scarf with a hook at each end: point-symmetric, so pulling the members apart pushes the hooks together. The Japanese okkake tsugi adds pegs driven from the side; drawn here without them.

## Sizes

| dimension | value |
|---|---|
| stock | 20 × 20 mm square |
| parts | part a, part b |
| length | 100 mm: a 76 mm slope between two 4 mm hooks |
| assembles | slides together sideways (across the members) |
| holds | pulling apart lengthwise (the hooks bear on each other) and bending; pin it against sliding sideways |

## 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/hooked-scarf-joint/index.json · license: https://xemstudio.com/files/hardware/hooked-scarf-joint/LICENSE.md

- hooked-scarf-joint-part-a: [STEP](https://xemstudio.com/files/hardware/hooked-scarf-joint/hooked-scarf-joint-part-a.step) · [STL](https://xemstudio.com/files/hardware/hooked-scarf-joint/hooked-scarf-joint-part-a.stl) — Member A with two hooks
- hooked-scarf-joint-part-b: [STEP](https://xemstudio.com/files/hardware/hooked-scarf-joint/hooked-scarf-joint-part-b.step) · [STL](https://xemstudio.com/files/hardware/hooked-scarf-joint/hooked-scarf-joint-part-b.stl) — Member B with the matching hooks
- hooked-scarf-joint-assembled: [STEP](https://xemstudio.com/files/hardware/hooked-scarf-joint/hooked-scarf-joint-assembled.step) · [STL](https://xemstudio.com/files/hardware/hooked-scarf-joint/hooked-scarf-joint-assembled.stl) — All parts in their assembled position (each part its own solid)

## Questions

**Does a hooked scarf hold in tension?**

Yes — both hooks bear when the members are pulled apart.

## Fits with

- [Kanawa tsugi (keyed hooked splice)](https://xemstudio.com/objects/kanawa-tsugi-splice/)
- [Plain scarf joint (1:4)](https://xemstudio.com/objects/plain-scarf-joint/)
- [Half lap splice joint](https://xemstudio.com/objects/half-lap-splice-joint/)