# Laboratory rubber stoppers #0–#13 (25 mm tall)

> What size rubber stopper fits a 25 mm test tube or a soda bottle?

- Category: Hardware › Found & household materials
- Kind: Standard part
- Basis: Standard US laboratory stopper sizes: top and bottom diameters, 25 mm tall; drawn as a straight taper (loft) between them
- Page: https://xemstudio.com/objects/rubber-stoppers/ · JSON: https://xemstudio.com/api/geometry?object=rubber-stoppers · Plain text: https://xemstudio.com/objects/rubber-stoppers/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses

**Exact dimensions.** Every file is drawn at true size with no printing tolerance. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your printer's or process's clearance before making the part.

## Notes

- Stopper number → top / bottom diameter (mm): #0 17/13, #1 19/15, #2 20/16, #3 24/18, #4 26/20, #5 27/23, #6 32/26, #6½ 34/27, #7 37/30, #8 41/33, #9 45/37, #10 50/42, #11 56/48, #12 64/54, #13 68/58; all 25 mm tall.
- Each file is a solid truncated cone between those diameters; one- and two-hole versions of the real stoppers take 5–7 mm tube.
- Pick the stopper whose mid-diameter is about 1 mm over the opening: 16 mm test tube #0, 20 mm #2, 25 mm #4/#5, 28 mm soda-bottle neck #6.
- The table gives the opening range each number seals.
- One file is a #4 bored through on its axis at Ø4 (stopper-4-bore-4): the stopper of the test-tube marble engine, with a 4 mm OD brass tube through it. The bore is my geometry, drawn at the tube's OD.

## Mating features (exact size; open press / slide / run / socket by your process clearance, leave designed and clamp as drawn)

| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| axial bore | Ø4 | brass-4mm tube OD | press | stopper-4-bore-4* |
| taper in a tube mouth | #4: Ø22.6 line 10.83 above the small end | 25 × 150 test tube bore Ø22.6 | press | stopper-4-bore-4* |

## Sizes

| number | top_mm | bottom_mm | height_mm | fits_opening_mm |
|---|---|---|---|---|
| #0 | 17 | 13 | 25 | 14–16 |
| #1 | 19 | 15 | 25 | 16–18 |
| #2 | 20 | 16 | 25 | 17–19 |
| #3 | 24 | 18 | 25 | 19–23 |
| #4 | 26 | 20 | 25 | 21–25 |
| #5 | 27 | 23 | 25 | 24–26 |
| #6 | 32 | 26 | 25 | 27–31 |
| #6.5 | 34 | 27 | 25 | 28–33 |
| #7 | 37 | 30 | 25 | 31–36 |
| #8 | 41 | 33 | 25 | 34–40 |
| #9 | 45 | 37 | 25 | 38–44 |
| #10 | 50 | 42 | 25 | 43–49 |
| #11 | 56 | 48 | 25 | 49–55 |
| #12 | 64 | 54 | 25 | 55–63 |
| #13 | 68 | 58 | 25 | 59–67 |

## Where the files are

- Wikipedia: [Bung](https://en.wikipedia.org/wiki/Bung) — web — CC BY-SA 4.0 (text)
- Wikipedia: [Cork (material)](https://en.wikipedia.org/wiki/Cork_(material)) — 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 (16 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/rubber-stoppers/index.json

- stopper-0: [STEP](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-0.step) · [STL](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-0.stl) — #0 stopper: Ø17 top, Ø13 bottom, 25 mm tall
- stopper-1: [STEP](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-1.step) · [STL](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-1.stl) — #1 stopper: Ø19 top, Ø15 bottom, 25 mm tall
- stopper-2: [STEP](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-2.step) · [STL](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-2.stl) — #2 stopper: Ø20 top, Ø16 bottom, 25 mm tall
- stopper-3: [STEP](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-3.step) · [STL](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-3.stl) — #3 stopper: Ø24 top, Ø18 bottom, 25 mm tall
- stopper-4: [STEP](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-4.step) · [STL](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-4.stl) — #4 stopper: Ø26 top, Ø20 bottom, 25 mm tall
- stopper-5: [STEP](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-5.step) · [STL](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-5.stl) — #5 stopper: Ø27 top, Ø23 bottom, 25 mm tall
- stopper-6: [STEP](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-6.step) · [STL](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-6.stl) — #6 stopper: Ø32 top, Ø26 bottom, 25 mm tall
- stopper-6-5: [STEP](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-6-5.step) · [STL](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-6-5.stl) — #6.5 stopper: Ø34 top, Ø27 bottom, 25 mm tall
- stopper-7: [STEP](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-7.step) · [STL](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-7.stl) — #7 stopper: Ø37 top, Ø30 bottom, 25 mm tall
- stopper-8: [STEP](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-8.step) · [STL](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-8.stl) — #8 stopper: Ø41 top, Ø33 bottom, 25 mm tall
- stopper-9: [STEP](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-9.step) · [STL](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-9.stl) — #9 stopper: Ø45 top, Ø37 bottom, 25 mm tall
- stopper-10: [STEP](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-10.step) · [STL](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-10.stl) — #10 stopper: Ø50 top, Ø42 bottom, 25 mm tall
- stopper-11: [STEP](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-11.step) · [STL](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-11.stl) — #11 stopper: Ø56 top, Ø48 bottom, 25 mm tall
- stopper-12: [STEP](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-12.step) · [STL](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-12.stl) — #12 stopper: Ø64 top, Ø54 bottom, 25 mm tall
- stopper-13: [STEP](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-13.step) · [STL](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-13.stl) — #13 stopper: Ø68 top, Ø58 bottom, 25 mm tall
- stopper-4-bore-4: [STEP](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-4-bore-4.step) · [STL](https://xemstudio.com/files/hardware/rubber-stoppers-and-corks/stopper-4-bore-4.stl) — #4 stopper (Ø26 top, Ø20 bottom, 25 tall) bored Ø4 on its axis for a 4 mm OD tube (the bore is my geometry, at the tube's OD)

## How it fits

### Goes in or on
- [Borosilicate test tubes, 10×75 to 30×200 mm](https://xemstudio.com/objects/borosilicate-test-tubes/): stopper closes the tube mouth
- [PET bottle necks: PCO 1881 (soda, 28 mm) and 38 mm (milk/juice)](https://xemstudio.com/objects/pet-bottle-necks-pco1881/): #6 in the 28 mm neck

### Alternatives
- [Wine cork #9: Ø24 × 44 mm and Ø24 × 49 mm](https://xemstudio.com/objects/wine-corks/): a parallel Ø24 cork for a 22–23 mm opening

## Questions

**What rubber stopper fits a 20 mm test tube?**

#2 (20 mm top, 16 mm bottom); #1 for 16–18 mm tubes, #4 for a 25 mm tube.

**Which stopper fits a soda bottle neck?**

#6 (32/26 mm) for the 28 mm PCO 1881 neck; #7 for a 38 mm neck.

**How tall is a lab rubber stopper?**

25 mm for every size from #0 to #13.

## Fits with

- [Wine cork #9: Ø24 × 44 mm and Ø24 × 49 mm](https://xemstudio.com/objects/wine-corks/)
- [Borosilicate test tubes, 10×75 to 30×200 mm](https://xemstudio.com/objects/borosilicate-test-tubes/)
- [PET bottle necks: PCO 1881 (soda, 28 mm) and 38 mm (milk/juice)](https://xemstudio.com/objects/pet-bottle-necks-pco1881/)
- [Mason jar flat lids: regular Ø70.00 and wide-mouth Ø86.00](https://xemstudio.com/objects/mason-jar-lid/)
- [Build list: Test-tube marble engine](https://xemstudio.com/objects/list-test-tube-marble-engine/)
- [Hobby brass tube (K&S), 1/16–21/32 in and 1–12 mm, telescoping](https://xemstudio.com/objects/brass-tube-ks/)