alcimedes
rule of thumb, iirc was back when you were allowed to beat your wife with a rod no thicker than your thumb.
the whole nine yards refers to the gunners in the (i think) b52 bombers. they bombers gun ammo came in 9 yard lengths. a harrowing trip would be one where you used "the whole nine yards".
and the one i learned today "hope against hope"
The phrase derives from the Bible (Romans 4:18 ): Saint Paul is writing about Abraham, 'Who against hope believed in hope, that he might become the father of many nations, according to that which was spoken.'"