I've done a fairly large amount of googling on two different occasions trying to figure out what neck finish I have on a particular bottle thread I have here.

I'm in europe and this is for a plastic water bottle, and most water bottles have this same thread, making the caps interchangeable. I've seen this thread across brands, across sizes, and across types of fluids held within (so not only water bottles). It seems pretty clear it's standardized- and since I've seen this thread on internationally distributed products I assume to some EU standard.

For anything I google, I'm already getting at least the first 10 results purpled out (previously visited). But the "T diameter" for my bottle doesn't match anything I've found on any charts whatsoever.

The diameter across the outside of the threads is (by my calipers) about 29.3mm, and it shouldn't be off by more than 0.1mm. The neck itself has 27.2mm diameter. It does look like what most websites describe as a 425 thread - 2 turns, fairly thin, not a long neck like the 415 - the thread starts at 3 different places across the neck circumference and is continuous (doesn't have little breaks like for example coca-cola bottles generally seem to have). The thread pitch does seem to be 2mm though it's hard to measure with too much accuracy so probably ±0.5mm. The neck does come with a snap ring (I think is the name) so it has a lip for it below the thread.

This is by the looks of it an incredibly widespread thread, though I can't find anything even remotely in the range of that 29.3mm.

Where can I find information on threadform and nominal dimensions? Is there a good way to identify bottle threads so I don't have to find myself in this predicament again?

  • $\begingroup$ what predicament are you in? $\endgroup$
    – jsotola
    Oct 16, 2023 at 1:26
  • $\begingroup$ @jsotola googling endlessly to no avail. ideally I'm looking for an answer like "there are these standards for europe, all plastic bottles must adhere to them so if you look at it long enough you'll find your answer for any plastic bottle thread". Was the rest of my question unclear? $\endgroup$
    – TrisT
    Oct 16, 2023 at 1:35
  • $\begingroup$ the post is clear ... I just did not see anything worthy of being called a predicament, so I thought that something was missing from the post $\endgroup$
    – jsotola
    Oct 16, 2023 at 1:38
  • $\begingroup$ file.yizimg.com/175706/2012051520551543.pdf $\endgroup$ Oct 16, 2023 at 11:26
  • $\begingroup$ isbt.com/threadspecs-downloads.asp $\endgroup$ Oct 16, 2023 at 11:27

1 Answer 1


Maximal google fu allowed me to find it.
It is EN 16592, called Packaging - Rigid plastic containers - PET finish 29/25.

Name is (seemingly purposefully) misleading because the nominal T is actually 29.4mm and the thread pitch is 2.17mm... just silly. The E is 27.6mm for anyone wondering, and the threadform is a buttress thread at 20° from square, with 0.25mm "nose" radius and 0.4mm fillets.

Getting taxed out of your ass and still have to pay for european comittee standards whose titles are picked to throw you off if you don't. "Gee, why do people hate the us here in the government?"


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