Ok never thought about indentifying my old tools but this is one of several

 That's a P1599 International Harvester wrench. Generally has a part number cast on bottom part of cross arm.

I have the same thing and I thought it was a oxy set wrench.

I have been told that is a plow wrench. Fairly common here but harder to find one that isn't broke.

 Irps lists usage as early disc harrows.

P1599. Very common out here in the Midwest.

Unlike the east.
We don't have disc harrow wrenches here.
We don't have disc harrows here.
We have rocks.
Rocks about 10" in diameter.
Rocks that fit nicely in between the discs...
And get stuck ;P

Here in Southeasternmost PA we live south of glaciated terrain. The plenitude of rocks that are found in moraines do not exist here.The topsoil in formerly forested lands is many feet deep in Lancaster County for example.  We can and do disk our lands freely.

On the downside, we do not have glacially formed lakes.