# Blind mortise and tenon joint

> What are the proportions of a mortise and tenon joint?

- Category: Joinery › Mortise & tenon joints
- Kind: Hardware
- Basis: Xem Studio design — geometry computed in the generator from traditional proportions
- Page: https://xemstudio.com/objects/blind-mortise-and-tenon-joint/ · JSON: https://xemstudio.com/api/geometry?object=blind-mortise-and-tenon-joint · Plain text: https://xemstudio.com/objects/blind-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 |
|---|---|---|
| 80.0 | 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).
- The classic frame joint: a tenon one third of the stock thick, stopped inside the mortised member so the end grain is hidden.
- Print the rail with the tenon flat on the bed; the stile prints with the mortise opening up.

## Sizes

| dimension | value |
|---|---|
| stock | 20 × 20 mm square |
| parts | stile, rail |
| tenon thickness | 6.67 mm (one third of the stock) |
| tenon width | 15 mm (2.5 mm shoulders) |
| tenon length | 15 mm (three quarters of the mortised member) |
| assembles | the tenon slides straight into the mortise |
| holds | racking; add a pin or glue against pull-out (see pegged and drawbored) |

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

- blind-mortise-and-tenon-joint-stile: [STEP](https://xemstudio.com/files/hardware/blind-mortise-and-tenon-joint/blind-mortise-and-tenon-joint-stile.step) · [STL](https://xemstudio.com/files/hardware/blind-mortise-and-tenon-joint/blind-mortise-and-tenon-joint-stile.stl) — Mortised member (stile / leg)
- blind-mortise-and-tenon-joint-rail: [STEP](https://xemstudio.com/files/hardware/blind-mortise-and-tenon-joint/blind-mortise-and-tenon-joint-rail.step) · [STL](https://xemstudio.com/files/hardware/blind-mortise-and-tenon-joint/blind-mortise-and-tenon-joint-rail.stl) — Tenoned member (rail)
- blind-mortise-and-tenon-joint-assembled: [STEP](https://xemstudio.com/files/hardware/blind-mortise-and-tenon-joint/blind-mortise-and-tenon-joint-assembled.step) · [STL](https://xemstudio.com/files/hardware/blind-mortise-and-tenon-joint/blind-mortise-and-tenon-joint-assembled.stl) — All parts in their assembled position (each part its own solid)

## Questions

**How thick should a tenon be?**

About one third of the stock: 6.67 mm in 20 mm stock.

**How long should a tenon be?**

Here 15 mm into a 20 mm member — about three quarters of its depth.

## Fits with

- [Through mortise and tenon joint](https://xemstudio.com/objects/through-mortise-and-tenon-joint/)
- [Haunched mortise and tenon joint](https://xemstudio.com/objects/haunched-mortise-and-tenon-joint/)
- [Pegged mortise and tenon joint](https://xemstudio.com/objects/pegged-mortise-and-tenon-joint/)
- [Loose tenon joint (floating tenon)](https://xemstudio.com/objects/loose-tenon-joint/)