# Slotted crank arm, Ø5 hub, 3 mm slot from 6 to 19 mm

> What is a slotted crank arm?

- 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/slotted-crank-arm-30/ · JSON: https://xemstudio.com/api/geometry?object=slotted-crank-arm-30 · Plain text: https://xemstudio.com/objects/slotted-crank-arm-30/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 |
|---|---|---|
| 37.0 | 14.0 | 5.0 |

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

## Notes

- Arm on a Ø14 hub (Ø5 bore) with a 3 mm wide slot whose centre line runs from 6 to 19 mm out: a Ø3 pin from another crank slides in it and drives it round.
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

## Sizes

| dimension | value |
|---|---|
| hub | Ø14, Ø5 bore |
| slot | 3 × 13 mm (centres 6–19 mm) |
| thickness | 5 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. 220: figure, his text and an animation](https://507movements.com/mm_220.html) — web — Publisher's page; dimensions are facts
- Xem Studio: [drawing](https://xemstudio.com/objects/offset-slotted-crank-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/slotted-crank-arm-30/index.json

- slotted-crank-arm-30: [STEP](https://xemstudio.com/files/hardware/slotted-crank-arm-30/slotted-crank-arm-30.step) · [STL](https://xemstudio.com/files/hardware/slotted-crank-arm-30/slotted-crank-arm-30.stl) — arm, z 0..5, slot on +X

## Questions

**What is a slotted crank arm?**

Arm on a Ø14 hub (Ø5 bore) with a 3 mm wide slot whose centre line runs from 6 to 19 mm out: a Ø3 pin from another crank slides in it and drives it round.

## Fits with

- [Offset cranks with slotted arm (variable-speed coupling, Whitworth principle)](https://xemstudio.com/objects/offset-slotted-crank-mechanism/)