Nickel-plated T-wrench w/9/16" square opening

[Wrenchmensch]

This T-wrench has a 9/16" square opening. It is 4 1/2" long, fairly heavy (.74 pounds), and is heavily plated.  My belief is that this is an old car wrench from the first quarter of the 20th century.  Judging from the quality of the tool, I would say the car was more likely an expensive one.  On the other hand, this wrench might also be an early motorcycle wrench.  The tool has no markings.

Your informed viewpoints, opinions, and WAGS about the intended application for this tool are needed!

[keykeeper]

Gas valve shut-off key for a stove, maybe?

Or possibly a key to shut off boiler water flow into the old iron radiator heaters commonly in use in larger buildings some years back?

[bc_z]

Gas valve shut-off key for a stove, maybe?

or for a gas log in a fireplace?

[rusty]

Valves with 1/2 inch stems are generally very large, think 6 inch pipe, that's a heck of a gas fire log....

[Wrenchmensch]

I want to add that nothing has been nickel plated in the last 90 years or more. 

[strik9]

My dad had an old Reknown brand wood stove in the basement that used a 9/16" square lever/crank type wrench to dump the grid under the fire into the ash box.
  That was a luxury stove from the 20's and  I wonder if this was for a similar purpose, it can't be for any high torque applications but it could be useful for this function.