Possibly found out some more info thanks to everyone’s help
Nice work. Now I am SURE we've discussed them before, the bold name, as well as those stiffeners in the square sockets, but I'll be danged if I can find it. Very cool. Patent 897,584, Carlson, Sep 1, 1908. DATAMP has a good write-up with links to other sets and ads, linked here.Possibly found out some more info thanks to everyone’s help