Late 1940s New Worlds are of a hybrid construction. Some of the frame joints are electro forge welded, similar to later bikes like the Varsity, and some are fillet brazed. Electro forge welding on some of the joints began fairly early in the history of the New World, around 1942 apparently with the I-series serial number bikes. But the process could not yet be applied to all of the frame joints. The joints where the electro forge welding process proved to be a challenge continued to be fillet brazed well after WWII. That's why when the frame is stripped you see brazing on some joints (the fillet brazed parts) and not on others (the welded parts).

Electro forge welding discussed:

https://www.sheldonbrown.com/varsity.html


Several of us who visit the Classic and Antique Bicycle Exchange website have been compiling a registry of New World bikes and looking at the evolution. Dozens have been documented dating to the era between 1939 and the early 1950s. "Miq" at the CABE has been keeping the chart up to date.

Latest chart here:
https://thecabe.com/forum/threads/wa...151709/page-80