# Rope sheave for Ø3 rope, pitch Ø80 (rope centre), Ø84.4 rim, Ø4 bore

> What groove does a rope sheave need?

- 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/rope-sheave-3mm-pitch-80/ · JSON: https://xemstudio.com/api/geometry?object=rope-sheave-3mm-pitch-80 · Plain text: https://xemstudio.com/objects/rope-sheave-3mm-pitch-80/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 |
|---|---|---|
| 84.4 | 8.0 | 84.4 |

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

## Notes

- Sheave 8 mm wide with a round-bottomed groove of radius 1.6 mm (1.07 × the Ø3 rope, the usual 6–10 % oversize) opening into 30° flanks; the rope rests on the groove bottom with its centre on a Ø80 circle, so a turn moves the rope 251.33 mm. Rim Ø84.4, Ø4 bore for a Ø4 pin.
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

## Sizes

| dimension | value |
|---|---|
| rope | Ø3 |
| pitch Ø (rope centre) | 80 mm |
| groove | R1.6, 30° flanks |
| rim | Ø84.4 × 8 mm |
| bore | Ø4 |

## 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. 12: figure, his text and an animation](https://507movements.com/mm_012.html) — web — Publisher's page; dimensions are facts
- Xem Studio: [drawing](https://xemstudio.com/objects/single-fixed-pulley-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/rope-sheave-3mm-pitch-80/index.json · license: https://xemstudio.com/files/hardware/rope-sheave-3mm-pitch-80/LICENSE.md

- rope-sheave-3mm-pitch-80: [STEP](https://xemstudio.com/files/hardware/rope-sheave-3mm-pitch-80/rope-sheave-3mm-pitch-80.step) · [STL](https://xemstudio.com/files/hardware/rope-sheave-3mm-pitch-80/rope-sheave-3mm-pitch-80.stl) — sheave, axis Y, centred on the origin

## Questions

**What groove does a rope sheave need?**

Sheave 8 mm wide with a round-bottomed groove of radius 1.6 mm (1.07 × the Ø3 rope, the usual 6–10 % oversize) opening into 30° flanks; the rope rests on the groove bottom with its centre on a Ø80 circle, so a turn moves the rope 251.33 mm. Rim Ø84.4, Ø4 bore for a Ø4 pin.

## Fits with

- [Single fixed pulley (power equals weight)](https://xemstudio.com/objects/single-fixed-pulley-mechanism/)
- [Blocks and tackle, two sheaves in each block (4 : 1)](https://xemstudio.com/objects/blocks-and-tackle-mechanism/)
- [Pulleys of the third system, three pulleys (7 : 1)](https://xemstudio.com/objects/third-system-pulleys-7-to-1-mechanism/)