Glass marbles 1/2 in, 5/8 in and Ø16 mm — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/glass-marbles/  (CC BY 4.0)
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
Catalog version: 2026-10-20

Sizes: see table below
- 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.

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

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Wikipedia: Craft stick — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Craft_stick
- Wikipedia: BB gun — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/BB_gun
- Wikipedia: Table tennis — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Table_tennis
- Long Earth Society: Engine builds (videos and write-ups) — web, video — LES site — https://longearthsociety.com/engineering/

Free files (CC BY 4.0, Xem Studio; STEP + STL, 3 parts): https://xemstudio.com/files/hardware/glass-marbles/index.json
API: https://xemstudio.com/api/geometry?object=glass-marbles