# Geneva stop finger wheel: Ø4 pin at r 23.51, Ø41.02 locking disc, Ø6 bore

> What is the finger wheel of a Geneva stop?

- Category: Mechanisms › Intermittent motion
- Kind: Modern device
- Basis: Xem Studio design following Brown's figure (1868); true size, no printing allowance
- Page: https://xemstudio.com/objects/geneva-stop-finger-wheel-r23-5-pin4/ · JSON: https://xemstudio.com/api/geometry?object=geneva-stop-finger-wheel-r23-5-pin4 · Plain text: https://xemstudio.com/objects/geneva-stop-finger-wheel-r23-5-pin4/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 |
|---|---|---|
| 53.02 | 53.02 | 10.0 |

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

## Notes

- Driver of a Geneva (Maltese cross) stop for a star on 40 mm centres: one Ø4 × 6 pin at radius 23.51 (= a·sin(π/5), so it enters and leaves the star's slots radially), a Ø41.02 × 6 locking disc that holds the star still between indexings, and a Ø53.02 × 4 carrier plate under both; Ø6 bore.
- The locking disc is cut back by the exact sweep of the star through one indexing (the star's outline in the wheel's frame at every 0.1° of the 108° engagement, a clearance surface kept as 0 mm facets), so disc and star only ever touch: on the disc's rim while locked, on the pin while indexing.
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

## Sizes

| dimension | value |
|---|---|
| pin | Ø4 at r 23.51 |
| locking disc | Ø41.02 × 6 |
| carrier | Ø53.02 × 4 |
| centres with the star | 40 mm |
| engagement | ±54° of the wheel's turn |
| bore | Ø6 |

## 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. 212: figure, his text and an animation](https://507movements.com/mm_212.html) — web — Publisher's page; dimensions are facts
- Xem Studio: [drawing](https://xemstudio.com/objects/geneva-stop-winding-stop-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/geneva-stop-finger-wheel-r23-5-pin4/index.json · license: https://xemstudio.com/files/hardware/geneva-stop-finger-wheel-r23-5-pin4/LICENSE.md

- geneva-stop-finger-wheel-r23-5-pin4: [STEP](https://xemstudio.com/files/hardware/geneva-stop-finger-wheel-r23-5-pin4/geneva-stop-finger-wheel-r23-5-pin4.step) · [STL](https://xemstudio.com/files/hardware/geneva-stop-finger-wheel-r23-5-pin4/geneva-stop-finger-wheel-r23-5-pin4.stl) — finger wheel, axis Z, disc z 0..6, carrier z -4..0, pin on +X

## Questions

**What is the finger wheel of a Geneva stop?**

Driver of a Geneva (Maltese cross) stop for a star on 40 mm centres: one Ø4 × 6 pin at radius 23.51 (= a·sin(π/5), so it enters and leaves the star's slots radially), a Ø41.02 × 6 locking disc that holds the star still between indexings, and a Ø53.02 × 4 carrier plate under both; Ø6 bore.

## Fits with

- [Geneva stop (Maltese cross stop-work): finger wheel limited to four turns](https://xemstudio.com/objects/geneva-stop-winding-stop-mechanism/)