# Oldham coupling (parallel-offset shaft coupling)

> How does an Oldham coupling handle offset shafts?

- Category: Mechanisms › Couplings & joints
- Kind: Hardware
- Basis: Xem Studio drawing; classic mechanism
- Page: https://xemstudio.com/objects/oldham-coupling/ · JSON: https://xemstudio.com/api/geometry?object=oldham-coupling · Plain text: https://xemstudio.com/objects/oldham-coupling/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

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

## Notes

- Two hubs with face tongues at 90° to each other and a centre disc slotted on both faces: the disc slides on both tongues, so shafts that are parallel but offset turn together.
- Speed is exactly 1:1 (no cyclic error, unlike a universal joint); the disc centre orbits at twice shaft speed with a radius of half the offset.
- Common on 3D-printer Z lead screws and pumps.
- Parts (each has its own page): oldham-coupling-hub-40, oldham-coupling-disc-40, shaft-couplers.

## Sizes

| parameter | value |
|---|---|
| diameter | 40 mm |
| max offset | ≈2 mm for this size |
| bores | Ø5 |

## Where the files are

- Xem Studio: [drawing](https://xemstudio.com/) — web — Publisher's page; dimensions are facts

## Free STEP/STL (1 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/oldham-coupling/index.json

- oldham-coupling-assembly: [STEP](https://xemstudio.com/files/hardware/oldham-coupling/oldham-coupling-assembly.step) · [STL](https://xemstudio.com/files/hardware/oldham-coupling/oldham-coupling-assembly.stl) — Assembled mechanism, all parts placed (STEP keeps each part separate)

## Questions

**How does an Oldham coupling handle offset shafts?**

Two hubs with face tongues at 90° to each other and a centre disc slotted on both faces: the disc slides on both tongues, so shafts that are parallel but offset turn together.

## Fits with

- [Oldham coupling hub Ø40, 5 mm bore](https://xemstudio.com/objects/oldham-coupling-hub-40/)
- [Oldham coupling centre disc Ø40](https://xemstudio.com/objects/oldham-coupling-disc-40/)
- [Flexible shaft couplers, 5–10 mm bores](https://xemstudio.com/objects/shaft-couplers/)