# Feed rack for a face spiral, module 1, 6 teeth, 19.05 × 8 × 7, curved teeth

> What rack runs on a face spiral?

- Category: Mechanisms › Screws & feeds
- Kind: Modern device
- Basis: Xem Studio design following Brown's figure (1868); true size, no printing allowance
- Page: https://xemstudio.com/objects/face-spiral-feed-rack-m1-6t-w8/ · JSON: https://xemstudio.com/api/geometry?object=face-spiral-feed-rack-m1-6t-w8 · Plain text: https://xemstudio.com/objects/face-spiral-feed-rack-m1-6t-w8/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 |
|---|---|---|
| 19.05 | 7.0 | 8.0 |

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

## Notes

- 6-tooth rack of module 1 (pitch 3.14 mm), 19.05 mm long, 8 wide, teeth 2.25 mm deep (tip at +1, root at -1.25 from the pitch line), body 6 mm below the pitch line. Generated by the spiral rib: in each of seven planes across the width the rib's section was swept past the rack and the envelope taken, so the teeth are straight-flanked (20°) but curved along the rack's width, following the spiral's curvature (the tooth at the edges of the face sits about 0.3 mm farther along than at the middle). The rack ends in the middle of a space at both ends.
- Slides radially over the disc's face, its teeth pointing at the face; one turn of the disc moves it one pitch.
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

## Sizes

| dimension | value |
|---|---|
| module | 1 |
| teeth | 6 |
| length | 19.05 mm |
| width | 8 mm |
| tooth depth | 2.25 mm |
| body | 6 mm below the pitch line |

## 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. 99: figure, his text and an animation](https://507movements.com/mm_099.html) — web — Publisher's page; dimensions are facts
- Xem Studio: [drawing](https://xemstudio.com/objects/face-spiral-rack-feed-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/face-spiral-feed-rack-m1-6t-w8/index.json · license: https://xemstudio.com/files/hardware/face-spiral-feed-rack-m1-6t-w8/LICENSE.md

- face-spiral-feed-rack-m1-6t-w8: [STEP](https://xemstudio.com/files/hardware/face-spiral-feed-rack-m1-6t-w8/face-spiral-feed-rack-m1-6t-w8.step) · [STL](https://xemstudio.com/files/hardware/face-spiral-feed-rack-m1-6t-w8/face-spiral-feed-rack-m1-6t-w8.stl) — rack along X (x -9.62..9.42), teeth pointing +Y, pitch line y = 0, width z -4..4

## Questions

**What rack runs on a face spiral?**

6-tooth rack of module 1 (pitch 3.14 mm), 19.05 mm long, 8 wide, teeth 2.25 mm deep (tip at +1, root at -1.25 from the pitch line), body 6 mm below the pitch line. Generated by the spiral rib: in each of seven planes across the width the rib's section was swept past the rack and the envelope taken, so the teeth are straight-flanked (20°) but curved along the rack's width, following the spiral's curvature (the tooth at the edges of the face sits about 0.3 mm farther along than at the middle). The rack ends in the middle of a space at both ends.

## Fits with

- [Face spiral on a disc as a drill feed: scroll driving a rack](https://xemstudio.com/objects/face-spiral-rack-feed-mechanism/)