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PET bottle necks: PCO 1881 (soda, 28 mm) and 38 mm (milk/juice)

What is the thread size of a soda bottle cap? · Standard part · basis: PCO 1881 (ISBT) neck finish; 38 mm three-start finish per ISBT; bottle body sizes typical

Long Earth Society build part. Clear pressure chambers and water-rocket bodies; printed caps thread straight on. The engines · all LES parts

sizes
3 in table

Notes

  • Soda / water bottle neck (PCO 1881): thread OD 27.43 mm, thread root 24.94 mm, 2 mm pitch single-start with 3 thread turns, neck height 17 mm from the support ring to the top, support ring Ø33 mm. Cap ID 28 mm. The older PCO 1810 is 21 mm tall with the same thread.
  • Milk / juice bottles: 38 mm finish (thread OD 37.5 mm, 3-start, 1.8 mm pitch, 10 mm tall). Water-cooler jugs are 55 mm.
  • Bottle bodies: 500 mL Ø65 × 200 mm; 1 L Ø80 × 270; 2 L Ø110 × 310, PET wall 0.3 mm. A printed PCO 1881 cap (thread modeled as a 27.9 mm bore with a 2 mm pitch groove) screws onto any soda bottle: pressure vessel to ~8 bar, the clear cylinder of a water-rocket or a pressure test rig. Never heat PET above 70 °C.

Sizes

finishthread_od_mmroot_mmpitch_mmheight_mmcap_id_mm
PCO 1881 (soda, 28 mm)27.4324.942.017.028.0
PCO 1810 (older 28 mm)27.4324.942.021.028.0
38 mm 3-start (milk/juice)37.534.01.810.038.0

Where the files are

Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.

WikipediaPlastic bottlewebCC BY-SA 4.0 (text)
ISBTPCO 1881 finish drawing (International Society of Beverage Technologists)PDFISBT publication verify
Long Earth SocietyEngine builds (videos and write-ups)web, videoLES site

Xem scan

Not needed Published standard; the sheet is the geometry.

Plain text: sheet.txt · JSON: /api/geometry?object=pet-bottle-necks-pco1881

length
Schematic, not to scale.

Fits with

Questions

What is the thread size on a soda bottle?

PCO 1881: 27.43 mm thread OD, 2 mm pitch, 17 mm tall neck; caps are 28 mm. All standard soda and water bottles use it.

Can I 3D print a cap for a soda bottle?

Yes: a 27.9 mm bore with a 2 mm pitch, 1.2 mm deep groove, 3 turns; print at 0.12 mm layers and it seals with a 1 mm silicone disc.