Am I a bit brace tool ?

[jimwrench]

 one piece malleable casting. Doesn't look quite right for brace bit as tang has constant taper. Anybody know its function ?

[john k]

I would say it is a socket tool for a brace, or a brace like tool.  With the cut out, it may have been  used in wagon manufacturing back when.   The wood farm wagon box was actually made rather lightly.  To haul a full load of grain, the box had to be held together front, middle, and rear with  reinforcing rods.  3/8 inch rod, with a loop on one end, and threaded on the other.  Instead of a plain square nut, it used a winged nut, with a 3 inch wing on one side only.  I can see where this socket would work to tighten  this wing nut.  Am thinking manufacturing, rather than a farm tool.    I try to collect brace sockets.