I'd be willing to bet money that, MAYBE, 1 in 100 people, (who use this phrase), 'RULE OF THUMB' , know where this came from. This may not be the right place to discuss this, but I just can't hold back! This archaic rule, was actually a law, (in the days of witch trials, and such). A man was allowed to beat his wife with a stick, IF... THE STICKS' CIRCUMFRENCE DID NOT EXCEED THAT OF HIS THUMB. As a survivor of domestic abuse myself, I would challenge everyone: to disclose this little snippit of info. to whomever they may hear useing this phrase.
Ant B, steps down from her soap box, goes to the nearest tree and cuts a branch, smaller than her pinky, then shakes it at the reflection she sees in the mirror. Hugs........................................