# Glass marbles 1/2 in, 5/8 in and Ø16 mm

> What is the diameter of a standard marble?

- Category: Hardware › Found & household materials
- Kind: Standard part
- Basis: Marbles are sized by diameter in 1/16 in steps, usually 1/2 to 3/4 in (marblecollecting.com); files are spheres at 1/2 in (Ø12.70), 5/8 in (Ø15.875) and Ø16.0
- Page: https://xemstudio.com/objects/glass-marbles/ · JSON: https://xemstudio.com/api/geometry?object=glass-marbles · Plain text: https://xemstudio.com/objects/glass-marbles/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

- Glass marbles are sized by diameter in 1/16 in steps and are usually 1/2 to 3/4 in. The files are spheres at 1/2 in (Ø12.70), 5/8 in (Ø15.875) and the metric Ø16.0.
- Tournament rules put shooters between 5/8 and 3/4 in.
- In the test-tube marble engine, four 5/8 in marbles roll inside a 25 × 150 tube (Ø22.6 bore) as the displacer; one marble fits across the bore, so they roll in single file.
- Marbles vary from piece to piece by a few tenths of a millimetre; measure the one you have before you draw anything around it.

## Sizes

| marble | dia_in | dia_mm |
|---|---|---|
| 1/2 in | 1/2 | 12.7 |
| 5/8 in | 5/8 | 15.875 |
| 16 mm | None | 16.0 |

## Where the files are

- Wikipedia: [Craft stick](https://en.wikipedia.org/wiki/Craft_stick) — web — CC BY-SA 4.0 (text)
- Wikipedia: [BB gun](https://en.wikipedia.org/wiki/BB_gun) — web — CC BY-SA 4.0 (text)
- Wikipedia: [Table tennis](https://en.wikipedia.org/wiki/Table_tennis) — 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 (3 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/glass-marbles/index.json

- marble-16mm: [STEP](https://xemstudio.com/files/hardware/sticks-skewers-wire-bbs/marble-16mm.step) · [STL](https://xemstudio.com/files/hardware/sticks-skewers-wire-bbs/marble-16mm.stl) — glass marble Ø16 (15.9); shooter Ø25
- marble-5-8in: [STEP](https://xemstudio.com/files/hardware/sticks-skewers-wire-bbs/marble-5-8in.step) · [STL](https://xemstudio.com/files/hardware/sticks-skewers-wire-bbs/marble-5-8in.stl) — glass marble 5/8 in (Ø15.875), the common size
- marble-1-2in: [STEP](https://xemstudio.com/files/hardware/sticks-skewers-wire-bbs/marble-1-2in.step) · [STL](https://xemstudio.com/files/hardware/sticks-skewers-wire-bbs/marble-1-2in.stl) — glass marble 1/2 in (Ø12.70)

## How it fits

### Goes in or on
- [Borosilicate test tubes, 10×75 to 30×200 mm](https://xemstudio.com/objects/borosilicate-test-tubes/): the marble displacer of the test-tube engine

### Alternatives
- [BBs: steel Ø4.5 mm (.177) and airsoft Ø6.0 mm](https://xemstudio.com/objects/steel-and-airsoft-bbs/): smaller balls, Ø4.5 and Ø6
- [Ping-pong ball Ø40 mm, 0.4 mm wall](https://xemstudio.com/objects/ping-pong-ball/): a larger, hollow, much lighter ball (Ø40)

## Questions

**What is the diameter of a marble?**

Marbles come in 1/16 in steps, usually 1/2 to 3/4 in; the common size is 5/8 in (15.875 mm, often sold as 16 mm).

**Are marbles all the same size?**

No; they are sized by the smallest sieve opening they pass, and individual marbles vary by a few tenths of a millimetre.

**What marbles go in a test-tube marble engine?**

5/8 in (Ø15.875) in a 25 × 150 tube (Ø22.6 bore): they roll in single file from end to end as the tube rocks.

## Fits with

- [BBs: steel Ø4.5 mm (.177) and airsoft Ø6.0 mm](https://xemstudio.com/objects/steel-and-airsoft-bbs/)
- [Ping-pong ball Ø40 mm, 0.4 mm wall](https://xemstudio.com/objects/ping-pong-ball/)
- [Ball bearings, 683 to 6210 and flanged F6xx (ISO 15)](https://xemstudio.com/objects/ball-bearings-metric/)
- [Build list: Test-tube marble engine](https://xemstudio.com/objects/list-test-tube-marble-engine/)
- [Borosilicate test tubes, 10×75 to 30×200 mm](https://xemstudio.com/objects/borosilicate-test-tubes/)