"They" have started to sell cable glands etc. with metric thread instead of the Pg conduit thread. This is driving us nuts! When making changes and additions to equipment we installad earlier, noting fits. It was bad enough before to find conversions from Pg 29 to Pg 21. Now we need conversions from PG 29 to M25... Doesn't exist, it seems.
C-H, I can't say that I've ever liked the Pg sizing system, for cable glands and so forth. I've always found the Metric threading sizes a lot easier to use, but that's only my personal view!. Oddly enough, (and I really hate to play the EU card here) there is (like for other things) an EU Directive on Cable Glands and the like, it's called prEN 50262, but I have a feeling it may apply to more than just Cable Glands. I didn't dare do a web search on it, for fear of getting lost in the technical data!.
Let's face it, these days if you're not young, you're old - Red Green
We do some plumbing as well (coolant water for machinery) and the funny thing is that most of what we use is 1/2" connections. That includes the gear that comes from Germany and Japan. The only exception is the American manufacturer of the plumbing parts: for some parts only metric threads are offered! The logic of this wonderful world...
We have a box marked "Weird brass fittings" where all unidentified threads go, like metric and NPT.
BTW, can someone explain why a 1/2" thread has a diameter of about 3/4"?