I was doing some research to try to determine the date of manufacture for a Sherman-Klove socket set that I own when I came across this Garage Journal site. If anyone can help me narrow down the production date of my set, I would greatly appreciate it. I have a Sherman-Klove 4168 W set that is in excellent to mint condition and was probably produced between 1941 and 1955, based on my research. All drive tools have the diamond <S-K> logo. The set has a 42470 knurled ratchet, a 40161extension, and a 41653 breaker bar with the larger 9/16 cross-bar hole (later versions had a 7/16 hole). I believe the set is missing a 41650 cross-bar. All sockets are knurled, have the chrome finish, and are marked with S-K (S-K CHROME markings were used until sometime between 1939 and 1944). All sockets also have the 401xx model numbers (model numbers were added in 1939), and have no recesses in the drive ends (recesses were added by 1955). The set has a 40190 swivel that I don't think came with the set, and is probably missing a 21/32 or 25/32 socket.
I have read that the 4168 set was first offered in 1939, but I have not been able to determine when it was last offered. If I could determine when the 41653 breaker bar switched to a 7/16 cross-bar hole, that would further narrow the possible dates. Thanks in advance to anyone that can provide assistance in this matter.