A saxophone that leaks at the neck does not play the way it should. This particular SML tenon and receiver was a mess. It was expanded to the point where it had cracks and was horribly out of round.
In replacing a tenon/receiver, the goal is to create an optimum fit that is perfectly round and is absolutely smooth at all transition points. The fit from the neck to the tenon and from the receiver to the body tube is stable and looks original. Soldering is touchy if you don’t want to damage existing lacquer or plating on the neck and body tube.
This SML was silver plated so I was able to plate the new pieces to match the rest of the horn perfectly before soldering. With lacquered horns, I patina the new pieces to match the horn and then apply lacquer to the tenon/receiver for as close a match as possible.