I don’t believe that Philadelphia is marked on any of the tools, just the label on the box. Lugz can probably verify that as I am currently away from my partial set.
You are correct. No brand markings of any kinds on any of the Phila Mfg Co tools. The sockets have size markings. That's it.
If your question,
@bryanrj, is prompted by an interest in identifying them for possible collecting, trust me when I say that the pieces will stand out to you right away in an old toolbox or bin at an estate sale or flea market due to their unusual size! They are HUGE compared to everything else in that era. Go ahead an ogle them in Pic 1 surrounded by some other sets I just grabbed randomly and let your eye go back and forth from other sets to the Phila set. Then spool through the other Pics and you will immediately see what I mean about them looking like the tools on 'roids in the lineup!
It's because of how they were made. Expediently! We don't know much about Phila Mfg except that they popped up during the war and disappeared afterwards. That they popped up in Philly is no surprise. The Navy's Supply Office was HQ'd there and the area has always been chock full of machine shops.
The sockets were machined out of cold rolled steel, then cold broached. They all look the same size because they only used two maybe three blanks for the bodies and they machined only the business end down from there. See Pics 2, 3, & 4. And it was a big blank! See Pic 5. Those are all sockets with 7/16" openings!
Now compare the shank of the sliding tee, the extension, and the spinner to some other brands. They used 3/8" rods for all of them and just machined the drive stud out of that. See Pics 6-9.
I've gone about this before, because it's so unusual, and why I find them so appealing (one of my favorite sets!), but your question prompted another run at it.
