# Snap-in slot covers for 20, 30, 40 and 10-series extrusion (100 mm)

> How do I cover the slot of 2020 extrusion?

- Category: Hardware › Framing
- Kind: Hardware
- Basis: Stem = slot opening × lip (exact), snap barb = opening + 1.2 (designed), cap = opening + 2.4 wide
- Page: https://xemstudio.com/objects/t-slot-covers/ · JSON: https://xemstudio.com/api/geometry?object=t-slot-covers · Plain text: https://xemstudio.com/objects/t-slot-covers/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses

**Exact dimensions.** Every file is drawn at true size with no printing tolerance. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your printer's or process's clearance before making the part.

## Notes

- Each cover is 100 mm long: a 1.2 mm thick cap 2.4 mm wider than the opening, a stem the slot opening wide by the lip thick, and a 1 mm snap barb 1.2 mm wider than the opening (0.6 mm each side, designed) that springs behind the lips.
- 20-series: cap 8.4, stem 6 × 1.8, barb 7.2. 30-series: cap 10.4, stem 8 × 2.5, barb 9.2. 40-series: cap 10.4, stem 8 × 3, barb 9.2. 10-series: cap 8.9, stem 6.5 × 2.3, barb 7.7.
- Covers hide wiring in the slot and keep debris out.

## Mating features (exact size; open press / slide / run / socket by your process clearance, leave designed and clamp as drawn)

| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| bracket / gusset / plate screw holes | Ø5.5 / 6.6 / 9.0 / 7.14 | M5 / M6 / M8 / 1/4-20 clearance | designed | all |
| slot-cover stem | slot opening × lip | slot opening | slide | slot-cover-* |
| slot-cover barb | opening + 1.2 | snaps behind the lips | designed | slot-cover-* |

## Sizes

| series | cap_mm | stem_mm | barb_mm | length_mm |
|---|---|---|---|---|
| 20 | 8.4 | 6 × 1.8 | 7.2 | 100 |
| 30 | 10.4 | 8 × 2.5 | 9.2 | 100 |
| 40 | 10.4 | 8 × 3 | 9.2 | 100 |
| 10 (1 in) | 8.9 | 6.5 × 2.3 | 7.7 | 100 |

## Where the files are

- Wikipedia: [T-slot nut](https://en.wikipedia.org/wiki/T-slot_nut) — web — CC BY-SA 4.0 (text)
- OpenBuilds: [Tee nuts and brackets for V-slot](https://openbuildspartstore.com/) — web, STEP — OpenBuilds site (verify at link)
- Long Earth Society: [Engine and rig builds on extrusion frames](https://longearthsociety.com/engineering/) — web, video — LES site

## Free STEP/STL (4 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/t-slot-covers/index.json

- slot-cover-20-100: [STEP](https://xemstudio.com/files/hardware/t-slot-brackets-and-nuts/slot-cover-20-100.step) · [STL](https://xemstudio.com/files/hardware/t-slot-brackets-and-nuts/slot-cover-20-100.stl) — 20-series snap-in slot cover, 100 mm: stem 6 wide (the slot opening, exact) with a snap barb
- slot-cover-30-100: [STEP](https://xemstudio.com/files/hardware/t-slot-brackets-and-nuts/slot-cover-30-100.step) · [STL](https://xemstudio.com/files/hardware/t-slot-brackets-and-nuts/slot-cover-30-100.stl) — 30-series snap-in slot cover, 100 mm: stem 8 wide (the slot opening, exact) with a snap barb
- slot-cover-40-100: [STEP](https://xemstudio.com/files/hardware/t-slot-brackets-and-nuts/slot-cover-40-100.step) · [STL](https://xemstudio.com/files/hardware/t-slot-brackets-and-nuts/slot-cover-40-100.stl) — 40-series snap-in slot cover, 100 mm: stem 8 wide (the slot opening, exact) with a snap barb
- slot-cover-10in-100: [STEP](https://xemstudio.com/files/hardware/t-slot-brackets-and-nuts/slot-cover-10in-100.step) · [STL](https://xemstudio.com/files/hardware/t-slot-brackets-and-nuts/slot-cover-10in-100.stl) — 10in-series snap-in slot cover, 100 mm: stem 6.5 wide (the slot opening, exact) with a snap barb

## How it fits

### Goes in or on
- [Aluminium T-slot extrusion: 2020, 2040, 2060, 2080, V-slot, 3030, 3060, 4040, 4080, 1010, 1515](https://xemstudio.com/objects/t-slot-extrusions/): stem in the slot opening, barb behind the lips

### Also needed
- [End caps for 20, 30, 40 and 10-series extrusion (1, 2 and 4 cells)](https://xemstudio.com/objects/t-slot-end-caps/): closes the profile ends

## Questions

**How wide is a 2020 slot cover?**

The stem is 6.0 mm (the opening), the cap 8.4 mm and the barb 7.2 mm.

**Can I make it longer?**

The file is 100 mm; the section is constant, so it can be extended to any length in CAD.

## Fits with

- [Slide-in T-nuts for 20, 30, 40 and 10-series (1 in) extrusion](https://xemstudio.com/objects/slide-in-t-nuts/)
- [End caps for 20, 30, 40 and 10-series extrusion (1, 2 and 4 cells)](https://xemstudio.com/objects/t-slot-end-caps/)
- [Aluminium T-slot extrusion: 2020, 2040, 2060, 2080, V-slot, 3030, 3060, 4040, 4080, 1010, 1515](https://xemstudio.com/objects/t-slot-extrusions/)
- [2020 aluminum extrusion](https://xemstudio.com/objects/2020-extrusion/)
- [Button head socket screws, M2–M8 (ISO 7380)](https://xemstudio.com/objects/button-head-screws-metric/)