# Right-triangle ruler 120 × 40 × 4 (half of a sliding parallel ruler)

> What is a sliding-triangle parallel ruler?

- 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/parallel-ruler-triangle-120x40/ · JSON: https://xemstudio.com/api/geometry?object=parallel-ruler-triangle-120x40 · Plain text: https://xemstudio.com/objects/parallel-ruler-triangle-120x40/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/)

## Overall (mm)

| length | width | height |
|---|---|---|
| 120.0 | 40.0 | 4.0 |

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

## Notes

- Right triangle with 120 and 40 mm legs, 4 mm thick: two of them, laid hypotenuse to hypotenuse, form a 120 × 40 rectangle whose long edges stay parallel as one triangle slides along the other.
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

## Sizes

| dimension | value |
|---|---|
| legs | 120 × 40 mm |
| hypotenuse | 126.49 mm |
| thickness | 4 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. 322: figure, his text and an animation](https://507movements.com/mm_322.html) — web — Publisher's page; dimensions are facts
- Xem Studio: [drawing](https://xemstudio.com/objects/sliding-triangle-parallel-ruler-mechanism/) — web — Publisher's page; dimensions are facts

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

Index: https://xemstudio.com/files/hardware/parallel-ruler-triangle-120x40/index.json

- parallel-ruler-triangle-120x40: [STEP](https://xemstudio.com/files/hardware/parallel-ruler-triangle-120x40/parallel-ruler-triangle-120x40.step) · [STL](https://xemstudio.com/files/hardware/parallel-ruler-triangle-120x40/parallel-ruler-triangle-120x40.stl) — triangle, right angle at the origin

## Questions

**What is a sliding-triangle parallel ruler?**

Right triangle with 120 and 40 mm legs, 4 mm thick: two of them, laid hypotenuse to hypotenuse, form a 120 × 40 rectangle whose long edges stay parallel as one triangle slides along the other.

## Fits with

- [Sliding-triangle parallel ruler](https://xemstudio.com/objects/sliding-triangle-parallel-ruler-mechanism/)