I was watching a 1934 Hollywood film today and one of the characters used the phrase, Of a Tuesday. I know of a Y-day has been a common phrase in British English in relatively recent times and assume it still is. But I don't think I've ever heard an American use this in real life or in a film before today, even though I watch a lot of 1930s and 1940s Hollywood movies.
The American actors of those times usually spoke in a quasi-generic-posh-British accent, which I think was not as common off the stage and screen (another question I'd love to get around to posting, though I suspect a definitive answer will be hard to come by.) So, perhaps the film folk also used Britishisms that also weren't common in American English.
I think I have a pretty good sense of what of a Y-day means, although the usage doesn't always exactly conform to it, and I find it very difficult to verbalize. If there is an American English version of of a Y-day, on would replace of, but I'm not so sure there is (especially not when it's used in what I think might have something to do with the subjunctive, but don't quote me on that.)
Google hasn't helped, especially since I don't know how to search on variables (although one Ngram does suggest something was happening of a Wednesday in about 1850.)
So, what are the meaning(s) and usage(s), history, and current popularity of the phrase of a Y-day both in American and British English?