# Internal (ring) gear, module 1, 60 teeth, Ø80

> What size is a module 1, 60 tooth internal gear?

- 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/internal-ring-gear-m1-60t/ · JSON: https://xemstudio.com/api/geometry?object=internal-ring-gear-m1-60t · Plain text: https://xemstudio.com/objects/internal-ring-gear-m1-60t/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 |
|---|---|---|
| 80.0 | 80.0 | 8.0 |

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

## Notes

- Ring gear with 60 internal involute teeth, module 1, 20°: pitch Ø60, roots at Ø62.5 (rp + 1.25 m), tooth tips at Ø58.24 (addendum shortened to 0.88 m, the usual internal-gear correction that keeps the tips clear of the pinion's base-circle interference point); outside Ø80 × 8 with four Ø3.4 holes on a Ø71.25 circle.
- A pinion of N teeth meshes inside at centre distance m(60 − N)/2: 20 T at 20 mm, 30 T at 15 mm, 18 T planets around a 24 T sun at 21 mm.
- 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 | 60 internal |
| pitch Ø | 60 mm |
| tip Ø (inside) | 58.24 mm |
| root Ø | 62.5 mm |
| outside | Ø80 × 8 mm |
| holes | 4 × Ø3.4 on Ø71.25 |

## 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. 34: figure, his text and an animation](https://507movements.com/mm_034.html) — web — Publisher's page; dimensions are facts
- Xem Studio: [drawing](https://xemstudio.com/objects/internal-gear-and-pinion-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/internal-ring-gear-m1-60t/index.json

- ring-gear-m1-60t: [STEP](https://xemstudio.com/files/hardware/internal-ring-gear-m1-60t/ring-gear-m1-60t.step) · [STL](https://xemstudio.com/files/hardware/internal-ring-gear-m1-60t/ring-gear-m1-60t.stl) — internal gear m1 60 T, Ø80 × 8, a space centred on +X

## Questions

**What size is a module 1, 60 tooth internal gear?**

Ring gear with 60 internal involute teeth, module 1, 20°: pitch Ø60, roots at Ø62.5 (rp + 1.25 m), tooth tips at Ø58.24 (addendum shortened to 0.88 m, the usual internal-gear correction that keeps the tips clear of the pinion's base-circle interference point); outside Ø80 × 8 with four Ø3.4 holes on a Ø71.25 circle.

**What is the centre distance of an internal gear and pinion?**

m × (N_ring − N_pinion) / 2, e.g. 20 mm for 60 and 20 teeth at module 1.

## Fits with

- [Internal gear and pinion, 60 : 20 (3 : 1, same direction)](https://xemstudio.com/objects/internal-gear-and-pinion-mechanism/)
- [Epicyclic (planetary) gear train: sun 24, planets 18, ring 60](https://xemstudio.com/objects/epicyclic-gear-train-mechanism/)
- [Tusi couple: straight line from a gear rolling inside a ring twice its size](https://xemstudio.com/objects/tusi-couple-straight-line-mechanism/)
- [One pinion driving an internal and a spur gear on one axis (two speeds)](https://xemstudio.com/objects/pinion-driving-internal-and-spur-gear-mechanism/)