The complete 1976 Simonds file catalog is available in 2 parts on this site. Taper saw files are in the American pattern section.
Some sources for new files are:
Any local hardware store. I am in mine several times a month and did not realize they had a few US made 6" double extra slims until recently, so I bought them all.
Indoor and outdoor flea markets can also be good sources for US made files of all kinds. There are usually several files in almost every toolbox I check, and taper saw files show up regularly. Even with toolbox knocks and a bit of rust, they are well worth the $1 or $2 each I have paid. Also, if you have an antique tool club near you, join and attend meetings, as other members are good sources for files.
|Heller Brothers Nucut files box|