Got at the flea market

Is *that* what it is!  I found one of these wrenches recently and wondered what it was for.

Railroad and theater use, to adjust the seat.

Cute.

I have an old desk to restore, I was wondering if one of my tappet wrenches would work.

Probably.

Some of the (often unmarked) stamped wrenches floating around were supplied with office furniture with adjustable feet to thread them up and down, usually they have an offset bent in the handle so you aren't rubbing your knuckles on the floor....

Skylab's wrench is kinda unusual in that they joined two pieces of sheet metal together, rather than just stamping the entire thing at once. I suppose they wanted a nice thick handle...

 American Seating Co had a couple of wrenchs. Here are two: the stamped handle wrench is 18044;the cast handled one is 13986.
Rathbone shows another wrench but I haven't found one of those.