# Single Spanish burton (3 : 1)

> How does a Spanish burton get 3 : 1 from two single blocks?

- Category: Mechanisms › Pulleys and tackle
- Kind: Hardware
- Basis: Xem Studio design following Brown No. 16 (1868)
- Page: https://xemstudio.com/objects/spanish-burton-single-mechanism/ · JSON: https://xemstudio.com/api/geometry?object=spanish-burton-single-mechanism · Plain text: https://xemstudio.com/objects/spanish-burton-single-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

- Rope 1 runs from the load over a fixed block and down to a runner block; rope 2 runs from the load over the runner and down to the hand. The runner is pulled down by both legs of rope 2 (2P) and held by rope 1, so rope 1 carries 2P; the load gets 2P + P: P = W/3.
- Here a pitch-Ø40 fixed block and a pitch-Ø20 runner; the two rope ends sit 30 mm apart on a load bar whose weight stem is on the line of the resultant (x = −10).
- Brown's No. 16 (Spanish barton). It is the 'third system' of pulleys with two sheaves: every rope ends on the load.
- Parts (each has its own page): tackle-beam-240-sockets, tackle-block-20-top-stem, tackle-block-10-top-socket, rope-sheave-3mm-pitch-40, rope-sheave-3mm-pitch-20, ropes-3mm-spanish-burton-single, tackle-weight-d40x40-socket, load-bar-40-sockets-m20-p10, dowel-pins-metric.
- Brown's movement No. 16 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.

## Sizes

| parameter | value |
|---|---|
| fixed block | pitch Ø40 |
| runner | pitch Ø20 |
| rope tensions | rope 1: 2P, rope 2: P |
| mechanical advantage | 3 |

## 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. 16: figure, his text and an animation](https://507movements.com/mm_016.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/spanish-burton-single-mechanism/index.json · license: https://xemstudio.com/files/hardware/spanish-burton-single-mechanism/LICENSE.md

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

## Questions

**How does a Spanish burton get 3 : 1 from two single blocks?**

Rope 1 runs from the load over a fixed block and down to a runner block; rope 2 runs from the load over the runner and down to the hand. The runner is pulled down by both legs of rope 2 (2P) and held by rope 1, so rope 1 carries 2P; the load gets 2P + P: P = W/3.

## Fits with

- [Tackle beam 240 × 20 × 12 with Ø3 sockets every 5 mm](https://xemstudio.com/objects/tackle-beam-240-sockets/)
- [Single block for a pitch-Ø40 sheave, stem up (fixed block)](https://xemstudio.com/objects/tackle-block-20-top-stem/)
- [Single runner block for a pitch-Ø20 sheave, rope socket on top](https://xemstudio.com/objects/tackle-block-10-top-socket/)
- [Rope sheave for Ø3 rope, pitch Ø40 (rope centre), Ø44.4 rim, Ø4 bore](https://xemstudio.com/objects/rope-sheave-3mm-pitch-40/)
- [Rope sheave for Ø3 rope, pitch Ø20 (rope centre), Ø24.4 rim, Ø4 bore](https://xemstudio.com/objects/rope-sheave-3mm-pitch-20/)
- [Ø3 ropes for the single spanish burton (drawn in place)](https://xemstudio.com/objects/ropes-3mm-spanish-burton-single/)
- [Weight Ø40 × 40 with a Ø3 top socket (394.58 g in steel)](https://xemstudio.com/objects/tackle-weight-d40x40-socket/)
- [Load bar 40 × 10 × 8 with 2 rope sockets and a weight stem](https://xemstudio.com/objects/load-bar-40-sockets-m20-p10/)
- [Dowel pins, 2–6 mm (ISO 2338 / DIN 6325)](https://xemstudio.com/objects/dowel-pins-metric/)