I can settle this debate very soon. I have a 1974 Colnago Super that I am about to strip for a repaint. We can see for sure then what it is. I do own 4 early Colnagos; all of which I have repainted myself, not to mention a good number of them for customers. All of them that I have seen so far have had machined (not cast) plugs brazed to Columbus double tapered seat stays. There's a straight line of brass where they meet. They are brazed to the seat lug with brass. That's all standard Italian protocol for many Italian brands of the period, from what I've seen. The other standard is the miter and cap method. But Colnagos are plugs, as most became during the Investment cast era. Ernesto just got there earlier as opposed to later.
La Mesa, CA
I fall into the fabricated school of top-eyes on this one...very unlikely to be a casting.
I reckon that the seat stay has received a short pointed stubby top-eye brazed into it. A thicker piece of mild steel plate has been filed to shape and contoured to fit the seat lug. THis has been laid against the seat lug, possibly even brazed into place, and then the seastay complete with stubby top-eye has been silver soldered onto it.
However knowing that Italian builders often like to take short cuts I think that it would have been possible for the stubby top-eye to have been brazed onto the shaped and contoured plate, then the completed top eye entered into the stay..and the whole assembly then silver-soldered..or even brazed with just a little care, onto the seat lug.
The third method would have been to tap the top-eye firmly into the seat-stay, place this against the seat lug with the decorative plate sandwiched or trapped berween the two parts, possibly apply a clamp or wrap some wire around the stays to keep the ensemble close and to prevent it from moving, and then to have brazed the whole lot in one shot.
The design and execution of any of these methods is not earth-shattering..and Ernesto would have been in his creative prime when he brazed up this frame.
Settle-Under-The Snow, UK _______________________________________________
Cheap Diet Help Tips. Click here.