Joe (and list),
First of all, sorry for the confusion of not responding to the list... I get the list in digest form, and sometimes think a message is off-list when it is on.
Singer lugs: The one "Italian-style" bike - I never paid attention to it. It's a pink bike, I am not even sure whether it really was made by Singer. Just like the carbon Singer Olivier Csuka rides sometimes...
For the more standard Singer lugs, check out Rivendell Reader 24 (my article on randonneur bikes), Vintage Bicycle Quarterly 1 (the 1962 Singer with the unified head tube) or Vintage Bicycle Quarterly 3 (mailed Tuesday) with a current-production bike. Or see Mark Petry's web site with his new bike.
As far as I know, all Singers had these lugs, except some very early ones that were fillet-brazed. So basically, if you have seen one Singer, you have seen them all. ;)
Ernest Csuka once showed me how they are filed from a blank. There is a tube that slips over the lug, which has the outline. Then a powered file is used to file the lug shape.
Special lugs (odd angles, oversize tubing, etc.) used to be made by welding pieces of tubing together. Then all lugs have brazing material added for the smooth radius. Then they are filed. You can see that nicely in the Japanese René Herse book. Herse and Singer, despite being archrivals (to this day!), used very similar lug styles.
Herse did not always build up the radius like Singer, but many bikes had that feature. He also built more bikes with the "Italian-style" lugs. Those are not as sought-after these days as the typical ones, despite being more rare.
Beautiful - yes, I agree, it is special touch, making the tubes flow together. D. Rebour claims it makes a stronger joint, in his book on cycling and cyclotourism. But how much weight does it add?
Jan Heine, Seattle