I would like to thank snapmom and Oldtuleguy for sharing pics of their SO Ferret collections and their knowledge about Ferret tools and tool boxes.
I have a Ferret Set tool box with the remnants of an oval label that appears to have been manufactured in 1937. There appears to be a small 1937 date code on the bottom of the box. It is possible that it is just a scratch that resembles the 1937 date code. My tool box is slightly different from the two Ferret Set tool boxes in Oldtuleguy's collection that are pictured on this thread in Post #2048. The older tool box pictured in Post #2048 has a V-shaped ratchet holder and a tab in the right hand corner of the tool box to keep the F-11 extension in place. The newer tool box pictured in Post #2048 has a straight ratchet holder, and it has no tab for the F-11 extension. My tool box has a V-shaped ratchet holder, and it has no tab for the F-11 extension. It is logical to assume that my tool box was made sometime in between the time that SO made the two toolboxes pictured in Post #2048.
The oldest tool in my Ferret Set tool box is the F10 breaker bar (1929). The oldest tool that is marked with the word "Ferret" is the F-6 extension (1935). The ratchet is model no. F70N. It has two date codes: 1945 and 1946. Most of the sockets are metric (8mm-19mm). The oldest socket was manufactured in 1948. The majority of the sockets were made in the 1950's. I am looking for a few more sockets (F10M, F12M, F13M, and F15M) and an F3 T bar. If you have any of them for sale, please contact me.