Welding leaves conflicting stresses , so once welded there is a solution heat treatment,

annealing and melting is not far apart in degrees ..

Frame is alignment jigged in the oven ..

in the 80's early Cannondale frames were delivered straight, but some of them had wavy tubes
from when they were soft during the normalizing heat treatment

Back then there was Vitus and AlAn out of France and Italy,, they were assembled by epoxy bonding the tubes to the other parts..

AlAn used a tapered thread , and before the epoxy cured the tubes were rotated,
(RH thread on one end LH on the other, like a tutnbuckle) so the tubes pulled the 'Lugs' over them..

Now Aluminum Tubes are Hydroformed into force & style, determined shapes with ends prepared to be ready for welding..


Think about a Trip to Taipei, & Taiwan in general, there is the biggest concentration of bike industry companies on the globe.

Adelaide Australia, is a lot closer than I am.

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