# Spur gears, module 0.8: 10 to 80 teeth (20° involute)

> What is the pitch diameter of a module 0.8 spur gear?

- Category: Hardware › Motion
- Kind: Hardware
- Basis: ISO 53 basic rack: 20° pressure angle, addendum m, dedendum 1.25 m; pitch Ø = m × teeth, tip Ø = m × (teeth + 2), root Ø = m × (teeth − 2.5)
- Page: https://xemstudio.com/objects/spur-gears-module-0-8/ · JSON: https://xemstudio.com/api/geometry?object=spur-gears-module-0-8 · Plain text: https://xemstudio.com/objects/spur-gears-module-0-8/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/)

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

## Notes

- Centre distance of two module 0.8 gears = m × (N1 + N2) / 2. Face width 6.4 mm, plain bore (add a hub, key or set screw to suit). Teeth below 17 are drawn without profile shift, so they undercut as real unshifted gears do.

## Sizes

| teeth | pitch_dia_mm | tip_dia_mm | root_dia_mm | face_mm | bore_mm |
|---|---|---|---|---|---|
| 10 | 8.0 | 9.6 | 6.0 | 6.4 | 2.0 |
| 12 | 9.6 | 11.2 | 7.6 | 6.4 | 3 |
| 14 | 11.2 | 12.8 | 9.2 | 6.4 | 3 |
| 15 | 12.0 | 13.6 | 10.0 | 6.4 | 4 |
| 16 | 12.8 | 14.4 | 10.8 | 6.4 | 4 |
| 18 | 14.4 | 16.0 | 12.4 | 6.4 | 4 |
| 20 | 16.0 | 17.6 | 14.0 | 6.4 | 5 |
| 22 | 17.6 | 19.2 | 15.6 | 6.4 | 5 |
| 24 | 19.2 | 20.8 | 17.2 | 6.4 | 6 |
| 25 | 20.0 | 21.6 | 18.0 | 6.4 | 6 |
| 28 | 22.4 | 24.0 | 20.4 | 6.4 | 7 |
| 30 | 24.0 | 25.6 | 22.0 | 6.4 | 8 |
| 32 | 25.6 | 27.2 | 23.6 | 6.4 | 8 |
| 35 | 28.0 | 29.6 | 26.0 | 6.4 | 9 |
| 36 | 28.8 | 30.4 | 26.8 | 6.4 | 9 |
| 40 | 32.0 | 33.6 | 30.0 | 6.4 | 10 |
| 42 | 33.6 | 35.2 | 31.6 | 6.4 | 11 |
| 45 | 36.0 | 37.6 | 34.0 | 6.4 | 12 |
| 48 | 38.4 | 40.0 | 36.4 | 6.4 | 13 |
| 50 | 40.0 | 41.6 | 38.0 | 6.4 | 13 |
| 56 | 44.8 | 46.4 | 42.8 | 6.4 | 15 |
| 60 | 48.0 | 49.6 | 46.0 | 6.4 | 16 |
| 64 | 51.2 | 52.8 | 49.2 | 6.4 | 17 |
| 70 | 56.0 | 57.6 | 54.0 | 6.4 | 19 |
| 72 | 57.6 | 59.2 | 55.6 | 6.4 | 19 |
| 80 | 64.0 | 65.6 | 62.0 | 6.4 | 22 |

## Where the files are

- ISO: [ISO 53 standard basic rack (20° pressure angle, addendum 1 m, dedendum 1.25 m) and ISO 54 modules](https://www.iso.org/standard/5768.html) — standard — ISO; dimensions are facts (verify at link)

## Free STEP/STL (26 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/spur-gears-module-0-8/index.json

- gear-m0-8-10t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-10t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-10t.stl) — module 0.8, 10 teeth: pitch Ø8, tip Ø9.6, root Ø6, face 6.4, bore Ø2
- gear-m0-8-12t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-12t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-12t.stl) — module 0.8, 12 teeth: pitch Ø9.6, tip Ø11.2, root Ø7.6, face 6.4, bore Ø3
- gear-m0-8-14t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-14t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-14t.stl) — module 0.8, 14 teeth: pitch Ø11.2, tip Ø12.8, root Ø9.2, face 6.4, bore Ø3
- gear-m0-8-15t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-15t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-15t.stl) — module 0.8, 15 teeth: pitch Ø12, tip Ø13.6, root Ø10, face 6.4, bore Ø4
- gear-m0-8-16t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-16t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-16t.stl) — module 0.8, 16 teeth: pitch Ø12.8, tip Ø14.4, root Ø10.8, face 6.4, bore Ø4
- gear-m0-8-18t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-18t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-18t.stl) — module 0.8, 18 teeth: pitch Ø14.4, tip Ø16, root Ø12.4, face 6.4, bore Ø4
- gear-m0-8-20t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-20t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-20t.stl) — module 0.8, 20 teeth: pitch Ø16, tip Ø17.6, root Ø14, face 6.4, bore Ø5
- gear-m0-8-22t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-22t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-22t.stl) — module 0.8, 22 teeth: pitch Ø17.6, tip Ø19.2, root Ø15.6, face 6.4, bore Ø5
- gear-m0-8-24t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-24t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-24t.stl) — module 0.8, 24 teeth: pitch Ø19.2, tip Ø20.8, root Ø17.2, face 6.4, bore Ø6
- gear-m0-8-25t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-25t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-25t.stl) — module 0.8, 25 teeth: pitch Ø20, tip Ø21.6, root Ø18, face 6.4, bore Ø6
- gear-m0-8-28t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-28t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-28t.stl) — module 0.8, 28 teeth: pitch Ø22.4, tip Ø24, root Ø20.4, face 6.4, bore Ø7
- gear-m0-8-30t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-30t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-30t.stl) — module 0.8, 30 teeth: pitch Ø24, tip Ø25.6, root Ø22, face 6.4, bore Ø8
- gear-m0-8-32t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-32t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-32t.stl) — module 0.8, 32 teeth: pitch Ø25.6, tip Ø27.2, root Ø23.6, face 6.4, bore Ø8
- gear-m0-8-35t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-35t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-35t.stl) — module 0.8, 35 teeth: pitch Ø28, tip Ø29.6, root Ø26, face 6.4, bore Ø9
- gear-m0-8-36t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-36t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-36t.stl) — module 0.8, 36 teeth: pitch Ø28.8, tip Ø30.4, root Ø26.8, face 6.4, bore Ø9
- gear-m0-8-40t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-40t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-40t.stl) — module 0.8, 40 teeth: pitch Ø32, tip Ø33.6, root Ø30, face 6.4, bore Ø10
- gear-m0-8-42t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-42t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-42t.stl) — module 0.8, 42 teeth: pitch Ø33.6, tip Ø35.2, root Ø31.6, face 6.4, bore Ø11
- gear-m0-8-45t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-45t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-45t.stl) — module 0.8, 45 teeth: pitch Ø36, tip Ø37.6, root Ø34, face 6.4, bore Ø12
- gear-m0-8-48t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-48t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-48t.stl) — module 0.8, 48 teeth: pitch Ø38.4, tip Ø40, root Ø36.4, face 6.4, bore Ø13
- gear-m0-8-50t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-50t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-50t.stl) — module 0.8, 50 teeth: pitch Ø40, tip Ø41.6, root Ø38, face 6.4, bore Ø13
- gear-m0-8-56t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-56t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-56t.stl) — module 0.8, 56 teeth: pitch Ø44.8, tip Ø46.4, root Ø42.8, face 6.4, bore Ø15
- gear-m0-8-60t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-60t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-60t.stl) — module 0.8, 60 teeth: pitch Ø48, tip Ø49.6, root Ø46, face 6.4, bore Ø16
- gear-m0-8-64t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-64t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-64t.stl) — module 0.8, 64 teeth: pitch Ø51.2, tip Ø52.8, root Ø49.2, face 6.4, bore Ø17
- gear-m0-8-70t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-70t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-70t.stl) — module 0.8, 70 teeth: pitch Ø56, tip Ø57.6, root Ø54, face 6.4, bore Ø19
- gear-m0-8-72t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-72t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-72t.stl) — module 0.8, 72 teeth: pitch Ø57.6, tip Ø59.2, root Ø55.6, face 6.4, bore Ø19
- gear-m0-8-80t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-80t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-0-8/gear-m0-8-80t.stl) — module 0.8, 80 teeth: pitch Ø64, tip Ø65.6, root Ø62, face 6.4, bore Ø22

## Questions

**Pitch diameter of a module 0.8, 20-tooth gear?**

16 mm; tip 17.6 mm.

**Centre distance?**

m × (N1 + N2) / 2: a 20 and a 40 tooth module 0.8 pair sit 24 mm apart.

## Fits with

- [Spur gears, module 0.5: 10 to 80 teeth (20° involute)](https://xemstudio.com/objects/spur-gears-module-0-5/)
- [Spur gears, module 1: 10 to 80 teeth (20° involute)](https://xemstudio.com/objects/spur-gears-module-1/)
- [Spur gears, module 1.25: 10 to 80 teeth (20° involute)](https://xemstudio.com/objects/spur-gears-module-1-25/)
- [Spur gears, module 1.5: 10 to 80 teeth (20° involute)](https://xemstudio.com/objects/spur-gears-module-1-5/)
- [Spur gears, module 2: 10 to 80 teeth (20° involute)](https://xemstudio.com/objects/spur-gears-module-2/)
- [Spur gears, involute 20°: module 0.5, 1 and 2, 12–60 teeth](https://xemstudio.com/objects/spur-gears-involute/)