# CD / DVD disc Ø120 × 1.2 mm with Ø15 hole (and mini CD Ø80)

> What are the dimensions of a CD and its centre hole?

- Category: Hardware › Found & household materials
- Kind: Standard part
- Basis: ECMA-130 / ISO 9660 physical disc: Ø120 × 1.2 mm, Ø15 mm centre hole; mini CD Ø80
- Page: https://xemstudio.com/objects/cd-dvd-discs/ · JSON: https://xemstudio.com/api/geometry?object=cd-dvd-discs · Plain text: https://xemstudio.com/objects/cd-dvd-discs/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses

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

## Notes

- CD, DVD and Blu-ray discs share one physical size: Ø120.0 × 1.2 mm with a Ø15.0 mm centre hole (held to +0.1), about 16 g.
- The mini CD is Ø80 × 1.2 with the same Ø15 hole, about 7 g.
- Both files are flat rings drawn at those nominal sizes; the hubs in the can-engine kit are drawn with a Ø15.0 spigot for the hole (see Mating features there).
- On the can engine I use a CD as the flywheel: 16 g spread out to Ø120.

## Sizes

| disc | dia_mm | thickness_mm | hole_mm | mass_g |
|---|---|---|---|---|
| CD / DVD / Blu-ray | 120 | 1.2 | 15 | 16 |
| mini CD | 80 | 1.2 | 15 | 7 |

## Where the files are

- Wikipedia: [Compact disc](https://en.wikipedia.org/wiki/Compact_disc) — web — CC BY-SA 4.0 (text)
- Wikipedia: [Hard disk drive platter](https://en.wikipedia.org/wiki/Hard_disk_drive_platter) — web — CC BY-SA 4.0 (text)
- Long Earth Society: [Engine builds (videos and write-ups)](https://longearthsociety.com/engineering/) — web, video — LES site

## Free STEP/STL (2 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/cd-dvd-discs/index.json

- cd-dvd-120: [STEP](https://xemstudio.com/files/hardware/cd-dvd-and-drive-platters/cd-dvd-120.step) · [STL](https://xemstudio.com/files/hardware/cd-dvd-and-drive-platters/cd-dvd-120.stl) — CD / DVD / Blu-ray: Ø120 × 1.2, Ø15 hole (Ø15.0 +0.1)
- mini-cd-80: [STEP](https://xemstudio.com/files/hardware/cd-dvd-and-drive-platters/mini-cd-80.step) · [STL](https://xemstudio.com/files/hardware/cd-dvd-and-drive-platters/mini-cd-80.stl) — Mini CD: Ø80 × 1.2, Ø15 hole

## How it fits

### Parts that fit it
- [CD and HDD-platter flywheel hubs: Ø15 and Ø25 spigots for Ø3 / 5 / 8 shafts](https://xemstudio.com/objects/flywheel-disc-hub/): Ø15 / Ø25 spigot in the disc's centre hole

### Goes in or on
- [Can-engine cap for 53.3, 58, 66 and 76.2 mm cans](https://xemstudio.com/objects/can-engine-cap/): Ø15 hole on the hub's Ø15.0 spigot

### Connects to
- [Bamboo skewer Ø3 × 300 mm](https://xemstudio.com/objects/bamboo-skewers/): hub carries the disc on a Ø3 shaft

### Alternatives
- [Hard-drive platters: 3.5 in Ø95 × 1.27 mm (Ø25 hole), 2.5 in Ø65 × 0.8 mm (Ø20 hole)](https://xemstudio.com/objects/hdd-platters/): heavier, flatter Ø95 / Ø65 discs
- [Crank discs for a Ø5 shaft, 10 to 30 mm stroke](https://xemstudio.com/objects/crank-discs-5mm-bore/): a drawn flywheel instead of a found disc

## Questions

**What is the diameter of a CD centre hole?**

15.0 mm (+0.1); the disc is Ø120 × 1.2 mm.

**Is a DVD the same size as a CD?**

Yes: Ø120 × 1.2 mm with a Ø15 hole; Blu-ray too.

**How big is a mini CD?**

Ø80 × 1.2 mm with the same Ø15 centre hole.

## Fits with

- [Hard-drive platters: 3.5 in Ø95 × 1.27 mm (Ø25 hole), 2.5 in Ø65 × 0.8 mm (Ø20 hole)](https://xemstudio.com/objects/hdd-platters/)
- [Can-engine cap for 53.3, 58, 66 and 76.2 mm cans](https://xemstudio.com/objects/can-engine-cap/)
- [Crank discs for a Ø5 shaft, 10 to 30 mm stroke](https://xemstudio.com/objects/crank-discs-5mm-bore/)
- [Bamboo skewer Ø3 × 300 mm](https://xemstudio.com/objects/bamboo-skewers/)
- [Aluminium beverage cans: 12 oz standard, 16 oz, 330/500 mL, sleek, slim, mini](https://xemstudio.com/objects/beverage-cans/)