# Pulley and gear unit: Ø40 × 16 flat pulley with a module 1.25, 32-tooth gear, Ø8 bore

> What is a pulley-and-gear unit?

- 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/pulley-gear-unit-40-m1-25-32t-bore8/ · JSON: https://xemstudio.com/api/geometry?object=pulley-gear-unit-40-m1-25-32t-bore8 · Plain text: https://xemstudio.com/objects/pulley-gear-unit-40-m1-25-32t-bore8/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 |
|---|---|---|
| 42.49 | 42.49 | 24.0 |

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

## Notes

- A Ø40 × 16 flat-belt pulley and a module 1.25, 32-tooth spur gear (pitch Ø40, 8 mm face) made in one piece, running loose on a Ø8 shaft: whichever unit the belt is on drives the gear cluster beside it, so shifting the belt changes speed.
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

## Sizes

| dimension | value |
|---|---|
| pulley | Ø40 × 16 |
| gear | module 1.25, 32 T, pitch Ø40, 8 face |
| bore | Ø8 (runs loose) |

## 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. 59: figure, his text and an animation](https://507movements.com/mm_059.html) — web — Publisher's page; dimensions are facts
- Xem Studio: [drawing](https://xemstudio.com/objects/belt-shifted-gears-three-speed-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/pulley-gear-unit-40-m1-25-32t-bore8/index.json · license: https://xemstudio.com/files/hardware/pulley-gear-unit-40-m1-25-32t-bore8/LICENSE.md

- pulley-gear-unit-40-m1-25-32t-bore8: [STEP](https://xemstudio.com/files/hardware/pulley-gear-unit-40-m1-25-32t-bore8/pulley-gear-unit-40-m1-25-32t-bore8.step) · [STL](https://xemstudio.com/files/hardware/pulley-gear-unit-40-m1-25-32t-bore8/pulley-gear-unit-40-m1-25-32t-bore8.stl) — unit, axis Z, pulley z 0..16, gear z 16..24, a tooth on +X

## Questions

**What is a pulley-and-gear unit?**

A Ø40 × 16 flat-belt pulley and a module 1.25, 32-tooth spur gear (pitch Ø40, 8 mm face) made in one piece, running loose on a Ø8 shaft: whichever unit the belt is on drives the gear cluster beside it, so shifting the belt changes speed.

## Fits with

- [Three speeds by shifting a belt over pulleys carrying gears (16 / 24 / 32 T)](https://xemstudio.com/objects/belt-shifted-gears-three-speed-mechanism/)