Thanks for your consideration! I still have a couple of bits of that size that I haven’t used, yet - well, roughtly, (3’x1" 8tpi) (I tend to work in inches because I’ve found it easier when working from American doco, though not always - parts availability is sometimes an issue).
I bought those when Masters was finishing up, and, because I was looking at building a Yeomans-styled concrete lathe. I opted, in the end, to try to build something that’s a bit more of a hybrid that steals from Yeomans, G.B. Round, Romig and Gingery. The idea/design is sound, enough, but I’m still finding alignment and boring difficult.