Have you tried to make a forked wrench?

Use 2 pcs.of flat steel the width of the flats on the nut and bend into a staple shape then weld the 2 together and weld a good size nut on top for a place to wrench.

Remember to keep the legs as short as possible...

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"When the Team Chief said.... You're trapped in a hole with nothing but a goat and a slinky, what do you do? Stubby said, I'm not sure but it won't end well for the goat...." ~(Overheard) Last day, Phase 3, Q Course