Join Date: Sep 2005
Location: Southern Florida
The headtube was cast together - it was joined with a flash weld at the top and downtubes just behind the taper - you'll notice the irregularity in the tubing at those spots.
As for the tubing (and the headtube as well), Schwinn rolled their own; hence the cheap weld under the BB. Same for the dropout joints and the crimped clearance.
They'll take just about any abuse you can throw at them, but that's all they're good for.