# Notched roller Ø18 × 4, Ø3 bore, 24 V-notches

> What are the rollers of a rolling parallel ruler?

- 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/notched-roller-d18x4-b3/ · JSON: https://xemstudio.com/api/geometry?object=notched-roller-d18x4-b3 · Plain text: https://xemstudio.com/objects/notched-roller-d18x4-b3/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 |
|---|---|---|
| 17.93 | 17.93 | 4.0 |

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

## Notes

- Ø18 × 4 roller with 24 V-notches 0.85 mm deep round its rim (they grip the paper so the ruler rolls without slipping) and a Ø3 bore; two on one axle make the ruler roll parallel to itself.
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

## Sizes

| dimension | value |
|---|---|
| diameter | 18 mm |
| width | 4 mm |
| notches | 24 × 0.85 mm deep, 90° |
| bore | Ø3 |

## 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. 323: figure, his text and an animation](https://507movements.com/mm_323.html) — web — Publisher's page; dimensions are facts
- Xem Studio: [drawing](https://xemstudio.com/objects/rolling-parallel-ruler-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/notched-roller-d18x4-b3/index.json · license: https://xemstudio.com/files/hardware/notched-roller-d18x4-b3/LICENSE.md

- notched-roller-d18x4-b3: [STEP](https://xemstudio.com/files/hardware/notched-roller-d18x4-b3/notched-roller-d18x4-b3.step) · [STL](https://xemstudio.com/files/hardware/notched-roller-d18x4-b3/notched-roller-d18x4-b3.stl) — roller, axis Z, z 0..4

## Questions

**What are the rollers of a rolling parallel ruler?**

Ø18 × 4 roller with 24 V-notches 0.85 mm deep round its rim (they grip the paper so the ruler rolls without slipping) and a Ø3 bore; two on one axle make the ruler roll parallel to itself.

## Fits with

- [Rolling parallel ruler (blade on two notched rollers)](https://xemstudio.com/objects/rolling-parallel-ruler-mechanism/)