# Shaft carried on the rims of two pairs of wheels (anti-friction bearing)

> What is a friction-wheel bearing?

- Category: Mechanisms › Belt and friction drives
- Kind: Hardware
- Basis: Xem Studio design following Brown No. 250 (1868)
- Page: https://xemstudio.com/objects/anti-friction-wheel-bearing-mechanism/ · JSON: https://xemstudio.com/api/geometry?object=anti-friction-wheel-bearing-mechanism · Plain text: https://xemstudio.com/objects/anti-friction-wheel-bearing-mechanism/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/)

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

## Notes

- Instead of turning in a plain bearing, the shaft lies in the angle between the rims of two wheels whose axles are parallel to it: as the shaft turns, the wheels turn with it, and the sliding friction of a journal becomes rolling friction at the rims plus a small journal friction at the wheels' axles, reduced in the ratio of their diameters.
- Here a Ø10 shaft on Ø40 wheels with axles 44 mm apart: the shaft's centre is 11.87 mm above the axles, touching each rim on a line. Two pairs, 70 mm apart along the shaft.
- Brown's No. 250 (anti-friction bearing: the shaft running on the circumferences of two wheels).
- Parts (each has its own page): anti-friction-wheel-40x10-bore8, linear-shafts-h6.
- Brown's movement No. 250 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.

## Sizes

| parameter | value |
|---|---|
| shaft | Ø10 |
| wheels | 4 × Ø40 × 10 |
| axle spacing | 44 mm |
| shaft height | 11.87 mm |

## Where the files are

- Henry T. Brown (1868, public domain): [Five Hundred and Seven Mechanical Movements — scan on archive.org](https://archive.org/details/fivehundredseven00browiala) — web — Publisher's page; dimensions are facts
- 507movements.com: [Brown's movement No. 250: figure, his text and an animation](https://507movements.com/mm_250.html) — web — Publisher's page; dimensions are facts

## Free STEP/STL (1 parts, Xem Studio Design License, Xem Studio)

Index: https://xemstudio.com/files/hardware/anti-friction-wheel-bearing-mechanism/index.json · license: https://xemstudio.com/files/hardware/anti-friction-wheel-bearing-mechanism/LICENSE.md

- anti-friction-wheel-bearing-mechanism-assembly: [STEP](https://xemstudio.com/files/hardware/anti-friction-wheel-bearing-mechanism/anti-friction-wheel-bearing-mechanism-assembly.step) · [STL](https://xemstudio.com/files/hardware/anti-friction-wheel-bearing-mechanism/anti-friction-wheel-bearing-mechanism-assembly.stl) — Assembled mechanism, all parts placed at one pose (STEP keeps each part separate)

## Questions

**What is a friction-wheel bearing?**

Instead of turning in a plain bearing, the shaft lies in the angle between the rims of two wheels whose axles are parallel to it: as the shaft turns, the wheels turn with it, and the sliding friction of a journal becomes rolling friction at the rims plus a small journal friction at the wheels' axles, reduced in the ratio of their diameters.

## Fits with

- [Anti-friction wheel Ø40 × 10, Ø8 bore](https://xemstudio.com/objects/anti-friction-wheel-40x10-bore8/)
- [Linear shafts Ø3 to Ø25 mm (h6), 100 to 1000 mm long](https://xemstudio.com/objects/linear-shafts-h6/)