When I was working on my Trailblazer the other day I needed to pull the front axle nut it is 35mm but I have an old 1 3/8" socket in what I thought was a 1/2" drive. I tried to put in on my impact wrench it was way TOO big. At first I just though it was worn out  but I'm not so sure about that now. Its right at a 9/16' drive opening and doesn't look more worn in the corners like I'd expect aslo the business end isn't all beat up. I couldn't find anything about a 9/16" drive on Alloy Arifacts. I also wondered about the maker, I've included a photo of the logo which is the only imprint on it I can find save the size. You guys got any ideas. At first I was thinking Blackhawk but I'm not sure about that. Also on GG please forgive cross posting

I just realized it was a SO overstrike tool but it still looks like 9/16".

yesterday there was a 9/16" on e-bay, I think it was a breaker bar, but not 100% sure.
it may have been an old Walden's.   I will try to find it later after lunch.
the sell went by something like ? shamo ?  sells a lot of Craftsmen tools. old-n-new.

 I have to apolagize,   I located the item that I mentioned earlier,

it is a 1/2" drive breaker bar with a 9/16" socket. (not a 9/16" breaker as I thought.)

it is a vintage  1/2" Frank Mossberg breaker bar with a patent date of 2/15/1910
the ebay seller is ( shamata ) also sells new/used craftsman tools.

Quote from: Fins/413 on January 18, 2014, 10:51:40 AM
I just realized it was a SO overstrike tool but it still looks like 9/16".

Go to collectingsnapon and I'm pretty sure you'll find out the answer to your question.

I think you'll find that is 5/8" drive that snap on made into the late 20's early 30's. As mentioned earlier, collecting snap on website, lots of good info. Looks like that sockets drive hole might be mushroomed from using as a bearing or seal driver which a lot of them were used for over the years since no one had those size drive tools anymore.

9/16 was a very popular drive size in HEX drive, several companies (NB,Husky, Plomb) used it. 9/16 in square drive is less common, Plomb used it , but in reverse (male sockets into female ratchet). Snappy I can't prove, but I seem to remember something about there keeping it for impact sockets for a little while after it was otherwise considered obsolete...

S/O made a 9/16 dr hex for their early valve adjustment tools.