Originally Posted by
krome
As far as I can tell, the techniques used in mass produced metal bicycle frames were thus:
Fillet brazed
silver brazed with lugs
Tig welding
Schwinn's Electro-forged
We're on the same page, but to add to your list.
brass brazed with lugs, internal or external
brass brazed of mitered tubes with little or no built up filet save for the bit that occurs naturally due to surface tension.
furnace brazing with copper, often used for attaching steerers to crowns as a sub assembly.
Also note that while Americans and British were brazing with gas, the Italians were doing very nice work with induction heating which produced very clean joints.