# Spur gears, module 3: 10 to 80 teeth (20° involute)

> What is the pitch diameter of a module 3 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-3/ · JSON: https://xemstudio.com/api/geometry?object=spur-gears-module-3 · Plain text: https://xemstudio.com/objects/spur-gears-module-3/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 3 gears = m × (N1 + N2) / 2. Face width 24 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 | 30.0 | 36.0 | 22.5 | 24.0 | 8 |
| 12 | 36.0 | 42.0 | 28.5 | 24.0 | 10 |
| 14 | 42.0 | 48.0 | 34.5 | 24.0 | 12 |
| 15 | 45.0 | 51.0 | 37.5 | 24.0 | 13 |
| 16 | 48.0 | 54.0 | 40.5 | 24.0 | 14 |
| 18 | 54.0 | 60.0 | 46.5 | 24.0 | 16 |
| 20 | 60.0 | 66.0 | 52.5 | 24.0 | 18 |
| 22 | 66.0 | 72.0 | 58.5 | 24.0 | 20 |
| 24 | 72.0 | 78.0 | 64.5 | 24.0 | 23 |
| 25 | 75.0 | 81.0 | 67.5 | 24.0 | 24 |
| 28 | 84.0 | 90.0 | 76.5 | 24.0 | 25 |
| 30 | 90.0 | 96.0 | 82.5 | 24.0 | 25 |
| 32 | 96.0 | 102.0 | 88.5 | 24.0 | 25 |
| 35 | 105.0 | 111.0 | 97.5 | 24.0 | 25 |
| 36 | 108.0 | 114.0 | 100.5 | 24.0 | 25 |
| 40 | 120.0 | 126.0 | 112.5 | 24.0 | 25 |
| 42 | 126.0 | 132.0 | 118.5 | 24.0 | 25 |
| 45 | 135.0 | 141.0 | 127.5 | 24.0 | 25 |
| 48 | 144.0 | 150.0 | 136.5 | 24.0 | 25 |
| 50 | 150.0 | 156.0 | 142.5 | 24.0 | 25 |
| 56 | 168.0 | 174.0 | 160.5 | 24.0 | 25 |
| 60 | 180.0 | 186.0 | 172.5 | 24.0 | 25 |
| 64 | 192.0 | 198.0 | 184.5 | 24.0 | 25 |
| 70 | 210.0 | 216.0 | 202.5 | 24.0 | 25 |
| 72 | 216.0 | 222.0 | 208.5 | 24.0 | 25 |
| 80 | 240.0 | 246.0 | 232.5 | 24.0 | 25 |

## 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-3/index.json

- gear-m3-10t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-10t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-10t.stl) — module 3, 10 teeth: pitch Ø30, tip Ø36, root Ø22.5, face 24, bore Ø8
- gear-m3-12t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-12t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-12t.stl) — module 3, 12 teeth: pitch Ø36, tip Ø42, root Ø28.5, face 24, bore Ø10
- gear-m3-14t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-14t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-14t.stl) — module 3, 14 teeth: pitch Ø42, tip Ø48, root Ø34.5, face 24, bore Ø12
- gear-m3-15t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-15t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-15t.stl) — module 3, 15 teeth: pitch Ø45, tip Ø51, root Ø37.5, face 24, bore Ø13
- gear-m3-16t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-16t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-16t.stl) — module 3, 16 teeth: pitch Ø48, tip Ø54, root Ø40.5, face 24, bore Ø14
- gear-m3-18t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-18t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-18t.stl) — module 3, 18 teeth: pitch Ø54, tip Ø60, root Ø46.5, face 24, bore Ø16
- gear-m3-20t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-20t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-20t.stl) — module 3, 20 teeth: pitch Ø60, tip Ø66, root Ø52.5, face 24, bore Ø18
- gear-m3-22t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-22t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-22t.stl) — module 3, 22 teeth: pitch Ø66, tip Ø72, root Ø58.5, face 24, bore Ø20
- gear-m3-24t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-24t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-24t.stl) — module 3, 24 teeth: pitch Ø72, tip Ø78, root Ø64.5, face 24, bore Ø23
- gear-m3-25t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-25t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-25t.stl) — module 3, 25 teeth: pitch Ø75, tip Ø81, root Ø67.5, face 24, bore Ø24
- gear-m3-28t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-28t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-28t.stl) — module 3, 28 teeth: pitch Ø84, tip Ø90, root Ø76.5, face 24, bore Ø25
- gear-m3-30t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-30t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-30t.stl) — module 3, 30 teeth: pitch Ø90, tip Ø96, root Ø82.5, face 24, bore Ø25
- gear-m3-32t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-32t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-32t.stl) — module 3, 32 teeth: pitch Ø96, tip Ø102, root Ø88.5, face 24, bore Ø25
- gear-m3-35t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-35t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-35t.stl) — module 3, 35 teeth: pitch Ø105, tip Ø111, root Ø97.5, face 24, bore Ø25
- gear-m3-36t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-36t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-36t.stl) — module 3, 36 teeth: pitch Ø108, tip Ø114, root Ø100.5, face 24, bore Ø25
- gear-m3-40t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-40t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-40t.stl) — module 3, 40 teeth: pitch Ø120, tip Ø126, root Ø112.5, face 24, bore Ø25
- gear-m3-42t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-42t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-42t.stl) — module 3, 42 teeth: pitch Ø126, tip Ø132, root Ø118.5, face 24, bore Ø25
- gear-m3-45t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-45t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-45t.stl) — module 3, 45 teeth: pitch Ø135, tip Ø141, root Ø127.5, face 24, bore Ø25
- gear-m3-48t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-48t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-48t.stl) — module 3, 48 teeth: pitch Ø144, tip Ø150, root Ø136.5, face 24, bore Ø25
- gear-m3-50t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-50t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-50t.stl) — module 3, 50 teeth: pitch Ø150, tip Ø156, root Ø142.5, face 24, bore Ø25
- gear-m3-56t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-56t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-56t.stl) — module 3, 56 teeth: pitch Ø168, tip Ø174, root Ø160.5, face 24, bore Ø25
- gear-m3-60t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-60t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-60t.stl) — module 3, 60 teeth: pitch Ø180, tip Ø186, root Ø172.5, face 24, bore Ø25
- gear-m3-64t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-64t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-64t.stl) — module 3, 64 teeth: pitch Ø192, tip Ø198, root Ø184.5, face 24, bore Ø25
- gear-m3-70t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-70t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-70t.stl) — module 3, 70 teeth: pitch Ø210, tip Ø216, root Ø202.5, face 24, bore Ø25
- gear-m3-72t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-72t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-72t.stl) — module 3, 72 teeth: pitch Ø216, tip Ø222, root Ø208.5, face 24, bore Ø25
- gear-m3-80t: [STEP](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-80t.step) · [STL](https://xemstudio.com/files/hardware/spur-gears-module-3/gear-m3-80t.stl) — module 3, 80 teeth: pitch Ø240, tip Ø246, root Ø232.5, face 24, bore Ø25

## Questions

**Pitch diameter of a module 3, 20-tooth gear?**

60 mm; tip 66 mm.

**Centre distance?**

m × (N1 + N2) / 2: a 20 and a 40 tooth module 3 pair sit 90 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 0.8: 10 to 80 teeth (20° involute)](https://xemstudio.com/objects/spur-gears-module-0-8/)
- [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, involute 20°: module 0.5, 1 and 2, 12–60 teeth](https://xemstudio.com/objects/spur-gears-involute/)