That is an unusual machine. National made a lot of machines that are badged with different names. You might try to join National Sewing Machine Company group at
https://groups.io/g/NSMCO I wonder, now, if perhaps it was not actually made by National. It looks like the same machine as seen at
https://tightacres.blogspot.com/2016...ti-zz2000.html which says "by a distributor for National Sewing Machine Co."
There is also a Borletti Group, but you have to join the main Group first. The main group is
https://necchisewingmachineclub.groups.io/g/main and then the sub-group is
https://necchisewingmachineclub.grou...lettiVigorelli
Good luck.
Janey - Neat people never make the exciting discoveries I do.
Not affiliated with off-site link(s)