# Borosilicate test tubes, 10×75 to 30×200 mm > What are standard test tube sizes and wall thickness? - Category: Hardware › Stirling & thermoacoustic - Kind: Hardware - Basis: Common laboratory sizes (OD × length), round bottom, rimless; wall 0.8–1.2 mm depending on size and maker - Page: https://xemstudio.com/objects/borosilicate-test-tubes/ · JSON: https://xemstudio.com/api/geometry?object=borosilicate-test-tubes · Plain text: https://xemstudio.com/objects/borosilicate-test-tubes/sheet.txt - License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses ## Notes - 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. ## Sizes | 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 | ## Where the files are - Wikipedia: [Test tube](https://en.wikipedia.org/wiki/Test_tube) — web — CC BY-SA 4.0 (text) - Pyrex / Corning: [Pyrex reusable test tubes, rimless (sizes)](https://www.corning.com/worldwide/en/products/life-sciences/products/glassware/pyrex-tubes.html) — web — Corning site terms (verify at link) - Long Earth Society: [Engine builds that use these parts (videos and write-ups)](https://longearthsociety.com/engineering/) — web, video — LES site ## Free STEP/STL (11 parts, CC BY 4.0, Xem Studio) Index: https://xemstudio.com/files/hardware/borosilicate-test-tubes/index.json - test-tube-10x75: [STEP](https://xemstudio.com/files/hardware/borosilicate-test-tubes/test-tube-10x75.step) · [STL](https://xemstudio.com/files/hardware/borosilicate-test-tubes/test-tube-10x75.stl) — Ø10 × 75 round-bottom, 1.0 mm wall (nominal) - test-tube-12x75: [STEP](https://xemstudio.com/files/hardware/borosilicate-test-tubes/test-tube-12x75.step) · [STL](https://xemstudio.com/files/hardware/borosilicate-test-tubes/test-tube-12x75.stl) — Ø12 × 75 round-bottom, 1.0 mm wall (nominal) - test-tube-13x100: [STEP](https://xemstudio.com/files/hardware/borosilicate-test-tubes/test-tube-13x100.step) · [STL](https://xemstudio.com/files/hardware/borosilicate-test-tubes/test-tube-13x100.stl) — Ø13 × 100 round-bottom, 1.0 mm wall (nominal) - test-tube-16x100: [STEP](https://xemstudio.com/files/hardware/borosilicate-test-tubes/test-tube-16x100.step) · [STL](https://xemstudio.com/files/hardware/borosilicate-test-tubes/test-tube-16x100.stl) — Ø16 × 100 round-bottom, 1.0 mm wall (nominal) - test-tube-16x125: [STEP](https://xemstudio.com/files/hardware/borosilicate-test-tubes/test-tube-16x125.step) · [STL](https://xemstudio.com/files/hardware/borosilicate-test-tubes/test-tube-16x125.stl) — Ø16 × 125 round-bottom, 1.0 mm wall (nominal) - test-tube-16x150: [STEP](https://xemstudio.com/files/hardware/borosilicate-test-tubes/test-tube-16x150.step) · [STL](https://xemstudio.com/files/hardware/borosilicate-test-tubes/test-tube-16x150.stl) — Ø16 × 150 round-bottom, 1.0 mm wall (nominal) - test-tube-18x150: [STEP](https://xemstudio.com/files/hardware/borosilicate-test-tubes/test-tube-18x150.step) · [STL](https://xemstudio.com/files/hardware/borosilicate-test-tubes/test-tube-18x150.stl) — Ø18 × 150 round-bottom, 1.0 mm wall (nominal) - test-tube-20x150: [STEP](https://xemstudio.com/files/hardware/borosilicate-test-tubes/test-tube-20x150.step) · [STL](https://xemstudio.com/files/hardware/borosilicate-test-tubes/test-tube-20x150.stl) — Ø20 × 150 round-bottom, 1.0 mm wall (nominal) - test-tube-25x150: [STEP](https://xemstudio.com/files/hardware/borosilicate-test-tubes/test-tube-25x150.step) · [STL](https://xemstudio.com/files/hardware/borosilicate-test-tubes/test-tube-25x150.stl) — Ø25 × 150 round-bottom, 1.0 mm wall (nominal) - test-tube-25x200: [STEP](https://xemstudio.com/files/hardware/borosilicate-test-tubes/test-tube-25x200.step) · [STL](https://xemstudio.com/files/hardware/borosilicate-test-tubes/test-tube-25x200.stl) — Ø25 × 200 round-bottom, 1.0 mm wall (nominal) - test-tube-30x200: [STEP](https://xemstudio.com/files/hardware/borosilicate-test-tubes/test-tube-30x200.step) · [STL](https://xemstudio.com/files/hardware/borosilicate-test-tubes/test-tube-30x200.stl) — Ø30 × 200 round-bottom, 1.0 mm wall (nominal) ## Questions **What are the dimensions of a 16x150 test tube?** 16 mm OD, 150 mm long, about 1.0 mm wall (14 mm ID), round bottom; it holds about 25 mL. **What test tube works as a Stirling engine cylinder?** 20×150 or 25×150 borosilicate (not soda-lime): the hot end takes a flame, the glass shows the displacer, and a printed collar at OD + 0.5 mm holds the cold end. **How much does test tube OD vary?** About ±0.5 mm between makers; design holders with 0.5 mm clearance and a silicone or felt liner. ## Fits with - [Tri-clamp spool (two ferrules on a tube), 1.5 and 2 inch](https://xemstudio.com/objects/tri-clamp-spool/) - [Copper pipe (ASTM B88 Type L and M), 1/4 to 2 inch](https://xemstudio.com/objects/copper-pipe-type-l-m/) - [O-rings, common metric sizes (ISO 3601)](https://xemstudio.com/objects/o-rings-metric/) - [Crank discs, connecting rods and flywheels for model engines](https://xemstudio.com/objects/crank-conrod-flywheel-kit/)