# PU pneumatic tube 4 to 12 mm OD (push-fit sizes)

> What is the ID of 6 mm PU pneumatic tube?

- Category: Hardware › Pipe & fittings
- Kind: Hardware
- Basis: ISO 6432-style metric PU pneumatic tube sizes (4 / 6 / 8 / 10 / 12 mm OD); each file a 50 mm length
- Page: https://xemstudio.com/objects/pu-pneumatic-tube/ · JSON: https://xemstudio.com/api/geometry?object=pu-pneumatic-tube · Plain text: https://xemstudio.com/objects/pu-pneumatic-tube/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses

**Exact dimensions.** True size, with no printing tolerance added.

## Notes

- PU pneumatic tube, OD × ID: 4×2.5, 6×4, 8×5.5, 10×6.5, 12×8 mm; each file is a 50 mm length at exact OD and ID.
- It is stiff tube made for push-fit fittings, typically rated 10 bar.
- Push-fit fittings grip the tube OD, so the push-fit socket is drawn at the tube OD exactly.
- On my pressurised engines the line is 6 mm PU into push-fits.

## Sizes

| od_mm | id_mm | wall_mm |
|---|---|---|
| 4 | 2.5 | 0.75 |
| 6 | 4 | 1.0 |
| 8 | 5.5 | 1.25 |
| 10 | 6.5 | 1.75 |
| 12 | 8 | 2.0 |

## Where the files are

- Wikipedia: [Hose barb](https://en.wikipedia.org/wiki/Hose_barb) — web — CC BY-SA 4.0 (text)
- Wikipedia: [Push-fit fitting](https://en.wikipedia.org/wiki/Push-to-connect_fitting) — web — CC BY-SA 4.0 (text)
- McMaster-Carr: [Tubing (free STEP per part, for your own design use; no redistribution)](https://www.mcmaster.com/products/tubing/) — STEP, PDF — McMaster-Carr site terms (verify at link)
- Long Earth Society: [Engine and rig builds](https://longearthsociety.com/engineering/) — web, video — LES site

## Free STEP/STL (5 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/pu-pneumatic-tube/index.json

- pu-tube-4x2.5-50: [STEP](https://xemstudio.com/files/hardware/silicone-tube-and-fittings/pu-tube-4x2.5-50.step) · [STL](https://xemstudio.com/files/hardware/silicone-tube-and-fittings/pu-tube-4x2.5-50.stl) — PU pneumatic tube 4 OD × 2.5 ID, 50 mm
- pu-tube-6x4-50: [STEP](https://xemstudio.com/files/hardware/silicone-tube-and-fittings/pu-tube-6x4-50.step) · [STL](https://xemstudio.com/files/hardware/silicone-tube-and-fittings/pu-tube-6x4-50.stl) — PU pneumatic tube 6 OD × 4 ID, 50 mm
- pu-tube-8x5.5-50: [STEP](https://xemstudio.com/files/hardware/silicone-tube-and-fittings/pu-tube-8x5.5-50.step) · [STL](https://xemstudio.com/files/hardware/silicone-tube-and-fittings/pu-tube-8x5.5-50.stl) — PU pneumatic tube 8 OD × 5.5 ID, 50 mm
- pu-tube-10x6.5-50: [STEP](https://xemstudio.com/files/hardware/silicone-tube-and-fittings/pu-tube-10x6.5-50.step) · [STL](https://xemstudio.com/files/hardware/silicone-tube-and-fittings/pu-tube-10x6.5-50.stl) — PU pneumatic tube 10 OD × 6.5 ID, 50 mm
- pu-tube-12x8-50: [STEP](https://xemstudio.com/files/hardware/silicone-tube-and-fittings/pu-tube-12x8-50.step) · [STL](https://xemstudio.com/files/hardware/silicone-tube-and-fittings/pu-tube-12x8-50.stl) — PU pneumatic tube 12 OD × 8 ID, 50 mm

## How it fits

### Goes in or on
- [Push-fit fitting envelopes: 4 / 6 / 8 mm tube, G1/8 and G1/4 thread stubs](https://xemstudio.com/objects/push-fit-fittings/): tube OD into the socket drawn at the OD

### Alternatives
- [Silicone tube 1 × 3 to 10 × 14 mm (ID × OD)](https://xemstudio.com/objects/silicone-tube/): soft tube for barbs

## Questions

**What is the ID of 6 mm PU tube?**

4 mm (6 × 4); 4 mm tube is 2.5 ID, 8 mm tube is 5.5 ID.

**What pressure is PU pneumatic tube rated for?**

Typically 10 bar.

## Fits with

- [Push-fit fitting envelopes: 4 / 6 / 8 mm tube, G1/8 and G1/4 thread stubs](https://xemstudio.com/objects/push-fit-fittings/)
- [Silicone tube 1 × 3 to 10 × 14 mm (ID × OD)](https://xemstudio.com/objects/silicone-tube/)
- [Hose barbs for 2, 3, 4, 6 and 8 mm ID tube](https://xemstudio.com/objects/hose-barbs/)