Interesting Anton, thanks for filling me in on that. Just to make things easier for you here, the frame parts are called tubes or tubing. Folks will understand what you are asking if you use that, its an easy thing to overlook if you aren't exposed to the nomenclature regularly.

Crocodile, hmmm, that is a new one on me, never heard that term applied to a classic or vintage bike before. Strange that metric standard tubing would limit you, even Reynolds had metric standard sizing as a part of their cycling. Using the seat post tube's inside diameter is a common means of narrowing down a bicycle's time frame and other aspects of its construction. Like I mentioned earlier, one of the really knowledgeable members can better help you with things about your frame, I don't want to steer you down the wrong path with my guesses about things.

Stick around please, and you should start a build post about your work on this bike, as you make it into your city bike.

Bill

Edit, I went to a translation website to try and get the correct spelling of the greeting/salutation/farewell, and they have several spellings listed there. I guess the translation between Cyrillic and English alphabet isn't exactly one to one. Anyway, I think you understood that I was telling you good-bye, and that I hope to see more form you here.