# Double-sided gear rack, module 1, 100 mm, pitch lines 12 mm apart

> What is a double-sided rack?

- 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/double-sided-rack-m1-100-pitch-12/ · JSON: https://xemstudio.com/api/geometry?object=double-sided-rack-m1-100-pitch-12 · Plain text: https://xemstudio.com/objects/double-sided-rack-m1-100-pitch-12/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 |
|---|---|---|
| 100.0 | 14.0 | 8.0 |

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

## Notes

- 100 × 8 bar with full-depth module 1 teeth (ISO 53, 20°) on both edges, tooth centres in line at x = kπ, pitch lines 12 mm apart (roots 9.5 apart); two Ø3.4 holes. Two gears of any equal size, one each side, drive it straight with the same force on both edges.
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

## Sizes

| dimension | value |
|---|---|
| module | 1 |
| length | 100 mm |
| pitch lines | y = ±6 |
| width | 8 mm |
| holes | 2 × Ø3.4 at x = ±40 |

## 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. 115: figure, his text and an animation](https://507movements.com/mm_115.html) — web — Publisher's page; dimensions are facts
- Xem Studio: [drawing](https://xemstudio.com/objects/double-rack-two-gears-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/double-sided-rack-m1-100-pitch-12/index.json · license: https://xemstudio.com/files/hardware/double-sided-rack-m1-100-pitch-12/LICENSE.md

- double-sided-rack-m1-100: [STEP](https://xemstudio.com/files/hardware/double-sided-rack-m1-100-pitch-12/double-sided-rack-m1-100.step) · [STL](https://xemstudio.com/files/hardware/double-sided-rack-m1-100-pitch-12/double-sided-rack-m1-100.stl) — rack, pitch lines y = ±6, a tooth centred at x = 0 on both edges, z 0..8

## Questions

**What is a double-sided rack?**

100 × 8 bar with full-depth module 1 teeth (ISO 53, 20°) on both edges, tooth centres in line at x = kπ, pitch lines 12 mm apart (roots 9.5 apart); two Ø3.4 holes. Two gears of any equal size, one each side, drive it straight with the same force on both edges.

## Fits with

- [Double-sided rack between two equal gears](https://xemstudio.com/objects/double-rack-two-gears-mechanism/)