I've been interested in the BU and the Supernovas. I think they are all metal and they run very nicely. I'm not sure when Necchi introduced the double cams, but I think it was some time in the 50s. I haven't time for it now, and I'm unfortunately not much help, but I'm sure the info is on the web. The BUs only had flat single layer cams. The later models had built in stitches. I think Necchi had both low shank and high shank models?
Last edited by Mickey2; 02-17-2018 at 07:46 AM.