# Triangular eccentric: curved (Reuleaux) triangle of width 30, pivoted at a corner

> What is a triangular eccentric?

- Category: Hardware › Mechanism parts
- Kind: Modern device
- Basis: Xem Studio design following Brown's figure (1868); true size, no printing allowance
- Page: https://xemstudio.com/objects/triangular-eccentric-reuleaux-w30/ · JSON: https://xemstudio.com/api/geometry?object=triangular-eccentric-reuleaux-w30 · Plain text: https://xemstudio.com/objects/triangular-eccentric-reuleaux-w30/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 |
|---|---|---|
| 30.0 | 37.0 | 18.0 |

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

## Notes

- Curved triangle of constant width 30 mm (three arcs of radius 30 about the opposite corners), 8 thick, with a Ø14 boss and a Ø6 blind bore at one corner: turned about that corner inside a yoke 30 mm wide, it moves the yoke with dwells at both ends.
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

## Sizes

| dimension | value |
|---|---|
| width | 30 mm (constant) |
| pivot | a corner, Ø14 boss, Ø6 blind bore |
| thickness | 8 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. 91: figure, his text and an animation](https://507movements.com/mm_091.html) — web — Publisher's page; dimensions are facts
- Xem Studio: [drawing](https://xemstudio.com/objects/triangular-eccentric-mechanism/) — web — Publisher's page; dimensions are facts

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

Index: https://xemstudio.com/files/hardware/triangular-eccentric-reuleaux-w30/index.json · license: https://xemstudio.com/files/hardware/triangular-eccentric-reuleaux-w30/LICENSE.md

- triangular-eccentric-reuleaux-w30: [STEP](https://xemstudio.com/files/hardware/triangular-eccentric-reuleaux-w30/triangular-eccentric-reuleaux-w30.step) · [STL](https://xemstudio.com/files/hardware/triangular-eccentric-reuleaux-w30/triangular-eccentric-reuleaux-w30.stl) — as drawn in the mechanism's own frame

## Questions

**What is a triangular eccentric?**

Curved triangle of constant width 30 mm (three arcs of radius 30 about the opposite corners), 8 thick, with a Ø14 boss and a Ø6 blind bore at one corner: turned about that corner inside a yoke 30 mm wide, it moves the yoke with dwells at both ends.

## Fits with

- [Triangular eccentric: curved triangle turning in a yoke (motion with dwells)](https://xemstudio.com/objects/triangular-eccentric-mechanism/)