in the 70's I had learned the silver-solder drawing torch work in Jewelry and metalsmithing courses,
so I though Why not..? so I winged it..
I later (on a bike tour) met a guy in Nottingham, he built jigless frames ,
with a rack of half round files, & a bench vice with wooden tube gripping blocks.
for pro racers , and even prototypes for Raleigh..
(I still have my bike with the DIY frame and fork.)
...