Don't know what this is...

[Debcrow]

This was in a SK toolbox I bought. It may not even be tool related.
Most of the rest of the tools in the box were much older than the toolbox. Some Walden I recognized as Model T specialty tools and others.
It is 13 1/4 inches overall. The square is 7/16 on both ends. I thought a drill bit extension, but the square hole with locking screw is not tapered. Possible jack extension? I just don't know.... Any ideas?

 

[4xdog]

Looks kinda like one of the segments of a spare tire winch crank. Toyota uses something similar.

 

[Farmer J.]

Looks kinda like one of the segments of a spare tire winch crank. Toyota uses something similar.

Yea, I have one exactly the same in every detail. Toyota jack/spare wheel crank handle extension from the 1980's. I still use the jack, it's handy in the workshop and outlived the Toyota Hi Lux, which was sadly destroyed in an accident whilst parked at the roadside.