# Double rack frame, module 1, racks 20 mm apart (120 × 44)

> What is a double rack frame?

- 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-rack-frame-120/ · JSON: https://xemstudio.com/api/geometry?object=double-rack-frame-120 · Plain text: https://xemstudio.com/objects/double-rack-frame-120/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 |
|---|---|---|
| 120.0 | 44.0 | 8.0 |

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

## Notes

- 120 × 44 × 8 frame with two facing module 1 racks whose pitch lines are 20 mm apart (one pitch diameter of a 20-tooth pinion), teeth in phase; a half-toothed pinion between them drives the frame one way on the upper rack and back on the lower.
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

## Sizes

| dimension | value |
|---|---|
| frame | 120 × 44 × 8 mm |
| racks | module 1, 96 mm, pitch lines 20 mm apart |
| end holes | 2 × Ø3 for guide rods/pins |

## 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. 114: figure, his text and an animation](https://507movements.com/mm_114.html) — web — Publisher's page; dimensions are facts
- Xem Studio: [drawing](https://xemstudio.com/objects/mutilated-gear-double-rack-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/double-rack-frame-120/index.json

- double-rack-frame-120: [STEP](https://xemstudio.com/files/hardware/double-rack-frame-120/double-rack-frame-120.step) · [STL](https://xemstudio.com/files/hardware/double-rack-frame-120/double-rack-frame-120.stl) — frame, pitch lines y = ±10

## Questions

**What is a double rack frame?**

120 × 44 × 8 frame with two facing module 1 racks whose pitch lines are 20 mm apart (one pitch diameter of a 20-tooth pinion), teeth in phase; a half-toothed pinion between them drives the frame one way on the upper rack and back on the lower.

## Fits with

- [Mutilated pinion and double rack (continuous rotation to reciprocation)](https://xemstudio.com/objects/mutilated-gear-double-rack-mechanism/)