Who made this wrench. They are common as dirt and I don't definitively know who made it. Bought this one last week not realizing it had 4 other copies in my basement.

Janesville Machine Co??

 Its possible Janesville could be the maker since they used letter designations on some of their wrenchs. Rathbone shows (A) (D) and (E) wrenchs by Janesville but I haven't seen any attribution of a (C) wrench to Janesville.

It is a Janesville. Later same wrench was Samson Tractor Co. No. 752424 (see Rathbone Volume Two page 256).

 Thanks I think I've been through this exercise before but I didn't record where I got ID before. Will make note in Rathbone. Checking basement I had tagged two of them as Janesville and one as Samson Tractor. I'll bring this last one to El Dorado as it won't fit on pegboard hook with others.