Bill D, the sense of "screw" in your "you can trade...a nail...for a screw!" is now widely understood even here in OZ but there was a time when it caused confusion and embarrassment here. Even until the late '50s, Australian slang for a good wage was "I'm on a good screw!"

But during the American occupation of Australia during WWII we were exposed to the US meaning, along with similar confusion about the term "fanny".

Thanks for reminding me.

Cheers, Rowan