About Angel Garcia's Cinelli,
>
> > http://www.wooljersey.com/
> >
I wondered:
> Maybe the Cinelli-Cinelli seat lug was a casting?
A guy who should know for sure filled me in but doesn't want the credit. Back then all three lugs were sand castings - the thin sheetmetal lugs didn't come along until the mid-70s. In comparison to the smooth investment-cast lugs that came along still later, the earlier sand castings were rough, crude and thick, requiring a lot of work to make 'em look nice.
So it looks like all 3 lugs on Angel's bike started out thick, and the head lugs just got more hand-filing than the seat lug.
That makes sense in a way, because thinning the lugs extends the fatigue lifetime of the tubing by reducing the "stress riser" - the abrupt change in thickness right at the lug edge, from tube+lug to just the tube. And the tubes are far more likely to fatigue at the head lugs. Top tube cracking at the seat lug (where Angel's bike is thick) is fairly rare, so there's little need to thin that lug - other than aesthetics.
Mark Bulgier
Seattle WA USA