Ping-pong ball Ø40 mm, 0.4 mm wall — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/ping-pong-ball/  (CC BY 4.0)
Basis: ITTF table-tennis ball: Ø40.0, 2.7 g; drawn as a hollow sphere with a 0.4 mm wall
Catalog version: 2026-10-20

Sizes: see table below
- A table-tennis ball is Ø40.0 mm and weighs 2.7 g (ITTF).
- The file is a hollow sphere: Ø40.0 outside, 0.4 mm wall (Ø39.2 inside).
- At 2.7 g it is the lightest ready-made hollow sphere of that size, which makes it useful as a displacer in small demonstrator engines.

ball  od_mm  wall_mm  mass_g
table-tennis ball  40.0  0.4  2.7

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, 1 parts): https://xemstudio.com/files/hardware/ping-pong-ball/index.json
API: https://xemstudio.com/api/geometry?object=ping-pong-ball