# Lower fiddle block: pitch-Ø19 and pitch-Ø25 sheaves side by side

> What is the lower fiddle block: pitch-ø19 and pitch-ø25 sheaves side by side?

- 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/tackle-block-fiddle-lower-19-25/ · JSON: https://xemstudio.com/api/geometry?object=tackle-block-fiddle-lower-19-25 · Plain text: https://xemstudio.com/objects/tackle-block-fiddle-lower-19-25/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 | 13.0 | 45.7 |

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

## Notes

- Block frame: two 2 mm cheeks either side of the sheaves (Ø4 pin holes), joined by bridges that carry Ø3 stems (into the beam, the floor plate or a weight's socket) and Ø3 rope-end sockets; every bridge sits clear of the rope's path. The stem sits on the line of the four supporting strands' resultant (x = 1.5).
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

## Sizes

| dimension | value |
|---|---|
| sheaves | pitch Ø19 at (-24.5, 0), pitch Ø25 at (27.5, 0) |
| cheeks | 2 mm, 9 mm apart (8 mm sheaves) |
| pins | Ø4 |
| stems | Ø3 × 8 at x = 1.5 down |

## 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/blocks-and-tackle-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/tackle-block-fiddle-lower-19-25/index.json · license: https://xemstudio.com/files/hardware/tackle-block-fiddle-lower-19-25/LICENSE.md

- tackle-block-fiddle-lower-19-25: [STEP](https://xemstudio.com/files/hardware/tackle-block-fiddle-lower-19-25/tackle-block-fiddle-lower-19-25.step) · [STL](https://xemstudio.com/files/hardware/tackle-block-fiddle-lower-19-25/tackle-block-fiddle-lower-19-25.stl) — frame, sheave plane y = 0, coordinates as in the mechanism

## Questions

**What is the lower fiddle block: pitch-ø19 and pitch-ø25 sheaves side by side?**

Block frame: two 2 mm cheeks either side of the sheaves (Ø4 pin holes), joined by bridges that carry Ø3 stems (into the beam, the floor plate or a weight's socket) and Ø3 rope-end sockets; every bridge sits clear of the rope's path. The stem sits on the line of the four supporting strands' resultant (x = 1.5).

## Fits with

- [Blocks and tackle, two sheaves in each block (4 : 1)](https://xemstudio.com/objects/blocks-and-tackle-mechanism/)