Rak, they are all variations on a theme: except for LEGO, they cut the brass out, bend it, solder it together and then bang it into shape. Alternately you spin the bell and then solder or fuse it to the rest. The final shape is done in all cases on a lathe. The skill comes in what you do on the lathe. I am sure that most artisans have produced a large amount of scrap before they got good. There are companies out there too that make bells for trumpet assemblers. AS far as Russian or Ukrainian language goes, I don't have any web links for Bachov, Schilsky, Kanstulova, Selmerskaya or F.E.пожилой!