Matty
My die filer is an Oliver S-4. Although the company, Oliver of Adrian, is still in business, the die filer is no longer manufactured. There were a number of companies who made die filers in the heyday of tool and die
shops.My guess is that CNC has eliminated much of the need for that machine. I'll bet Ron can confirm this.
That said, the people at Oliver were very helpful with information about the original buyer of my machine, the fact that it was a special order with their largest table, a manual and a PDF of the drawing for a missing lower file clamp.
They still have most parts and files.
The machine tool dealer in New Jersey where I got my Bridgeport has a shelf full of die filers. Many look to have been "unloved" where they worked. My S-4, which I got at Cabin Fever last year, is in beautiful condition. I also bought a large selection of files. I've later discovered that Victor Machinery Exchange in Brooklyn, also has files. A simple solution is to take a "normal"" file, grind or cut off the tang, and make a flat at the other end for clamping. This then cuts on the downstroke.
One of the vendors at Cabin Fever (Martin ) makes a casting set for a small die filer.
Some pics of mine here
http://s1126.photobucket.com/user/sshire/library/Oliver die filer?sort=3&page=1