# Haunched mortise and tenon joint

> What is a haunched mortise and tenon?

- Category: Joinery › Mortise & tenon joints
- Kind: Hardware
- Basis: Xem Studio design — geometry computed in the generator from traditional proportions
- Page: https://xemstudio.com/objects/haunched-mortise-and-tenon-joint/ · JSON: https://xemstudio.com/api/geometry?object=haunched-mortise-and-tenon-joint · Plain text: https://xemstudio.com/objects/haunched-mortise-and-tenon-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 |
|---|---|---|
| 50.0 | 80.0 | 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).
- At a corner the tenon is narrowed so the mortise does not break out of the end of the stile; the short haunch fills the groove line and stops the rail twisting.

## Sizes

| dimension | value |
|---|---|
| stock | 20 × 20 mm square |
| parts | stile, rail |
| tenon | 11 × 6.67 mm, 15 mm long |
| haunch | 6.5 mm wide, 5 mm long |
| assembles | straight in |
| holds | racking and twisting at a corner; the haunch keeps the rail from twisting |

## 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/haunched-mortise-and-tenon-joint/index.json · license: https://xemstudio.com/files/hardware/haunched-mortise-and-tenon-joint/LICENSE.md

- haunched-mortise-and-tenon-joint-stile: [STEP](https://xemstudio.com/files/hardware/haunched-mortise-and-tenon-joint/haunched-mortise-and-tenon-joint-stile.step) · [STL](https://xemstudio.com/files/hardware/haunched-mortise-and-tenon-joint/haunched-mortise-and-tenon-joint-stile.stl) — Stile ending at the corner: mortise plus a short haunch slot
- haunched-mortise-and-tenon-joint-rail: [STEP](https://xemstudio.com/files/hardware/haunched-mortise-and-tenon-joint/haunched-mortise-and-tenon-joint-rail.step) · [STL](https://xemstudio.com/files/hardware/haunched-mortise-and-tenon-joint/haunched-mortise-and-tenon-joint-rail.stl) — Rail with a tenon and a short haunch
- haunched-mortise-and-tenon-joint-assembled: [STEP](https://xemstudio.com/files/hardware/haunched-mortise-and-tenon-joint/haunched-mortise-and-tenon-joint-assembled.step) · [STL](https://xemstudio.com/files/hardware/haunched-mortise-and-tenon-joint/haunched-mortise-and-tenon-joint-assembled.stl) — All parts in their assembled position (each part its own solid)

## Questions

**What is the haunch for?**

It keeps the rail from twisting and fills the panel groove at the corner of a frame.

## Fits with

- [Blind mortise and tenon joint](https://xemstudio.com/objects/blind-mortise-and-tenon-joint/)
- [Corner bridle joint (open mortise and tenon)](https://xemstudio.com/objects/corner-bridle-joint/)