Where Does "Wham, bam" Come From?

I’m back to inviting readers to submit quotations whose origins they want me to try to trace, using my book, The Yale Book of Quotations, and my more recent researches.
merry staser asked:

“‘Wham, bam … thank you ma’m'”  We have been looking for this one all over and can’t seem to find out where it came from … (travelling in a carriage … was one we found … but not a full explanation). Thanks.”

I don’t have a full explanation (and I’m not sure one is necessary, the meaning of the expression is obvious).  The earliest occurrence I know of is in the 1948 play Mister Roberts, where a sailor character says “Well there goes the liberty.  That was sure a wham-bam-thank-you ma’am!”
tunaman asked:

“I heard that Benjamin Franklin once said (in ‘Poor Richard’s Almanac’) ‘a watched pot never boils over’, which is a totally different concept than ‘a watched pot never boils’.  I once looked for this online, but didn’t come up with much one way or the other. Any ideas?”

The usual form of the proverb is, of course, “a watched pot never boils.”  Neither form appears in Benjamin Franklin’s writings.
Do any readers have any other quotations whose origins they would like me to attempt to trace?