# M8 captive nut slot (side-loaded)

> How do you make a side-loaded M8 nut slot?

- Category: Joinery › 3D-print connectors
- Kind: Hardware
- Basis: Xem Studio design — geometry computed in the generator from traditional proportions
- Page: https://xemstudio.com/objects/captive-nut-slot-m8/ · JSON: https://xemstudio.com/api/geometry?object=captive-nut-slot-m8 · Plain text: https://xemstudio.com/objects/captive-nut-slot-m8/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 |
|---|---|---|
| 21.0 | 31.5 | 16.8 |

**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 slot that takes an M8 nut from the side, for a nut in the middle of a part (e.g. under a clamp screw).
- Drawn at the nut's true size: add your fit allowance to the slot width and height. The slot ceiling is a short bridge.

## Sizes

| dimension | value |
|---|---|
| stock | 21 × 31.5 × 16.8 mm test block |
| parts | block, nut |
| slot | 13 mm wide (nut across flats), 6.8 mm tall (nut height), open to the side |
| screw hole | Ø8 mm |
| assembles | slide the nut in from the side, screw through |
| holds | the nut mid-part, where a top pocket can't reach |

## 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/captive-nut-slot-m8/index.json · license: https://xemstudio.com/files/hardware/captive-nut-slot-m8/LICENSE.md

- captive-nut-slot-m8-block: [STEP](https://xemstudio.com/files/hardware/captive-nut-slot-m8/captive-nut-slot-m8-block.step) · [STL](https://xemstudio.com/files/hardware/captive-nut-slot-m8/captive-nut-slot-m8-block.stl) — Block with a 13 mm wide slot from the side, 6.8 mm tall, and a Ø8 screw hole
- captive-nut-slot-m8-nut: [STEP](https://xemstudio.com/files/hardware/captive-nut-slot-m8/captive-nut-slot-m8-nut.step) · [STL](https://xemstudio.com/files/hardware/captive-nut-slot-m8/captive-nut-slot-m8-nut.stl) — M8 hex nut, in place
- captive-nut-slot-m8-assembled: [STEP](https://xemstudio.com/files/hardware/captive-nut-slot-m8/captive-nut-slot-m8-assembled.step) · [STL](https://xemstudio.com/files/hardware/captive-nut-slot-m8/captive-nut-slot-m8-assembled.stl) — All parts in their assembled position (each part its own solid)

## Questions

**How wide is an M8 nut slot?**

13 mm (across flats) by 6.8 mm tall at true size, plus your fit allowance.

## Fits with

- [M8 nut trap (hex pocket for an ISO 4032 nut)](https://xemstudio.com/objects/nut-trap-m8/)
- [Hex nuts, M2–M8 (ISO 4032)](https://xemstudio.com/objects/hex-nuts-metric/)