# Rectangular (oblong) gear, module 1.5, 40 teeth, follower

> What shape is the follower of a rectangular gear pair?

- Category: Mechanisms › Gears
- Kind: Modern device
- Basis: Xem Studio design following Brown's figure (1868); true size, no printing allowance
- Page: https://xemstudio.com/objects/rectangular-gear-m1-5-40t-follower/ · JSON: https://xemstudio.com/api/geometry?object=rectangular-gear-m1-5-40t-follower · Plain text: https://xemstudio.com/objects/rectangular-gear-m1-5-40t-follower/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 |
|---|---|---|
| 57.11 | 73.34 | 12.0 |

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

## Notes

- Pitch curve computed as the exact rolling mate of the driver at 58.37 mm centres (r₂ = a − r₁, dθ₂ = r₁/r₂·dθ₁, one turn each).
- Teeth generated by a 20° basic rack rolled round the pitch curve (spline outline within 0.010 mm of the generated curve); Ø8 bore at the pivot, 12 mm face.
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

## Sizes

| dimension | value |
|---|---|
| module | 1.5 |
| teeth | 40 |
| size | 57.11 × 73.35 mm over tips |
| bore | Ø8 |
| face | 12 mm |

## 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. 30: figure, his text and an animation](https://507movements.com/mm_030.html) — web — Publisher's page; dimensions are facts
- Xem Studio: [drawing](https://xemstudio.com/objects/rectangular-gears-oblong-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/rectangular-gear-m1-5-40t-follower/index.json · license: https://xemstudio.com/files/hardware/rectangular-gear-m1-5-40t-follower/LICENSE.md

- rectangular-gear-m1-5-40t-follower: [STEP](https://xemstudio.com/files/hardware/rectangular-gear-m1-5-40t-follower/rectangular-gear-m1-5-40t-follower.step) · [STL](https://xemstudio.com/files/hardware/rectangular-gear-m1-5-40t-follower/rectangular-gear-m1-5-40t-follower.stl) — gear, pivot on the Z axis, z 0..12

## Questions

**What shape is the follower of a rectangular gear pair?**

Pitch curve computed as the exact rolling mate of the driver at 58.37 mm centres (r₂ = a − r₁, dθ₂ = r₁/r₂·dθ₁, one turn each).

## Fits with

- [Rectangular (oblong) gears for a varying speed](https://xemstudio.com/objects/rectangular-gears-oblong-mechanism/)