# Edge-runner (chaser) mill: two rollers on one axle rolling round a pan

> How does an edge-runner mill crush?

- Category: Mechanisms › Belt and friction drives
- Kind: Hardware
- Basis: Xem Studio design following Brown No. 375 (1868)
- Page: https://xemstudio.com/objects/edge-runner-mill-mechanism/ · JSON: https://xemstudio.com/api/geometry?object=edge-runner-mill-mechanism · Plain text: https://xemstudio.com/objects/edge-runner-mill-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

- Two heavy wheels on a horizontal axle that passes through a vertical spindle: turning the spindle drags the wheels round the pan, and because a wheel's inner edge travels a shorter circle than its outer edge the rim both rolls and skids — it crushes by weight and grinds by the skid.
- Drawn with Ø50 × 16 runners at 50 mm radius on a Ø5 × 150 axle, Ø12 spindle, Ø160 pan; each runner touches the pan floor along a line (contact only).
- Brown's No. 375 (chasers, edge runners, for crushing and mixing); mortar, pigment and gunpowder mills.
- Parts (each has its own page): edge-runner-pan-d160, edge-runner-d50x16-b5, edge-runner-spindle-d12x100, linear-shafts-h6.
- Brown's movement No. 375 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.

## Sizes

| parameter | value |
|---|---|
| runners | 2 × Ø50 × 16 |
| track radius | 50 mm |
| pan | Ø160 |
| spindle | Ø12 × 100 |

## 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. 375: figure, his text and an animation](https://507movements.com/mm_375.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/edge-runner-mill-mechanism/index.json · license: https://xemstudio.com/files/hardware/edge-runner-mill-mechanism/LICENSE.md

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

## Questions

**How does an edge-runner mill crush?**

Two heavy wheels on a horizontal axle that passes through a vertical spindle: turning the spindle drags the wheels round the pan, and because a wheel's inner edge travels a shorter circle than its outer edge the rim both rolls and skids — it crushes by weight and grinds by the skid.

## Fits with

- [Edge-runner pan Ø160, 8 mm rim, Ø12 centre bore](https://xemstudio.com/objects/edge-runner-pan-d160/)
- [Edge runner (chaser) Ø50 × 16, Ø5 bore](https://xemstudio.com/objects/edge-runner-d50x16-b5/)
- [Vertical spindle Ø12 × 100 with a Ø5 cross hole 35 mm up](https://xemstudio.com/objects/edge-runner-spindle-d12x100/)
- [Linear shafts Ø3 to Ø25 mm (h6), 100 to 1000 mm long](https://xemstudio.com/objects/linear-shafts-h6/)