Borosilicate test tubes, 10×75 to 30×200 mm — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/borosilicate-test-tubes/  (CC BY 4.0)
Basis: Common laboratory sizes (OD × length), round bottom, rimless; wall 0.8–1.2 mm depending on size and maker
Catalog version: 2026-10-20

Sizes: see table below
- Sizes are OD × length in mm: 10×75, 12×75, 13×100, 16×100, 16×125, 16×150 (the classic), 18×150, 20×150, 25×150, 25×200, 30×200. OD tolerance about ±0.5 mm, so measure before a press fit.
- Wall: about 1.0 mm up to 20 mm OD, 1.2 mm for 25–30. Rimmed versions add a 1.5 mm flare at the mouth.
- Why it's here: a 20×150 or 25×150 borosilicate tube is the displacer cylinder of a low-temperature Stirling / thermoacoustic demonstrator; it survives a 300 °C hot end and lets you watch the displacer. Mount in a silicone-lined printed collar at OD + 0.5 mm.

size  od_mm  length_mm  wall_mm  id_mm
10 × 75  10  75  1.0  8.0
12 × 75  12  75  1.0  10.0
13 × 100  13  100  1.0  11.0
16 × 100  16  100  1.0  14.0
16 × 125  16  125  1.0  14.0
16 × 150  16  150  1.0  14.0
18 × 150  18  150  1.0  16.0
20 × 150  20  150  1.0  18.0
25 × 150  25  150  1.2  22.6
25 × 200  25  200  1.2  22.6
30 × 200  30  200  1.2  27.6

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Wikipedia: Test tube — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Test_tube
- Pyrex / Corning: Pyrex reusable test tubes, rimless (sizes) — web — Corning site terms [verify license at link] — https://www.corning.com/worldwide/en/products/life-sciences/products/glassware/pyrex-tubes.html
- Long Earth Society: Engine builds that use these parts (videos and write-ups) — web, video — LES site — https://longearthsociety.com/engineering/

Free files (CC BY 4.0, Xem Studio; STEP + STL, 11 parts): https://xemstudio.com/files/hardware/borosilicate-test-tubes/index.json
API: https://xemstudio.com/api/geometry?object=borosilicate-test-tubes