# Rack guide base 170 × 20 with side rail and spring seat

> What guides the 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/rack-guide-base-170-spring-seat/ · JSON: https://xemstudio.com/api/geometry?object=rack-guide-base-170-spring-seat · Plain text: https://xemstudio.com/objects/rack-guide-base-170-spring-seat/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 |
|---|---|---|
| 170.0 | 20.0 | 16.0 |

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

## Notes

- 4 mm base plate with a 6 mm side rail the rack slides against and a 10 mm end wall the return spring bears on, 30 mm from the rack's end.
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

## Sizes

| dimension | value |
|---|---|
| base | 170 × 20 × 4 |
| rail | 6 × 8 |
| spring seat | 10 × 20 × 12 |

## 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. 81: figure, his text and an animation](https://507movements.com/mm_081.html) — web — Publisher's page; dimensions are facts
- Xem Studio: [drawing](https://xemstudio.com/objects/mutilated-gear-spring-rack-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/rack-guide-base-170-spring-seat/index.json · license: https://xemstudio.com/files/hardware/rack-guide-base-170-spring-seat/LICENSE.md

- rack-guide-base-170-spring-seat: [STEP](https://xemstudio.com/files/hardware/rack-guide-base-170-spring-seat/rack-guide-base-170-spring-seat.step) · [STL](https://xemstudio.com/files/hardware/rack-guide-base-170-spring-seat/rack-guide-base-170-spring-seat.stl) — as drawn in the mechanism's own frame

## Questions

**What guides the rack?**

4 mm base plate with a 6 mm side rail the rack slides against and a 10 mm end wall the return spring bears on, 30 mm from the rack's end.

## Fits with

- [Mutilated spur gear moving a rack, a spring bringing it back](https://xemstudio.com/objects/mutilated-gear-spring-rack-mechanism/)