Speaker 1: Welcome to brain Stuff from how stuff works dot com,
Speaker 1: where smart happens the high on Marshall Brain with today's question,
Speaker 1: can you explain the diameter measurements used in nails? You
Speaker 1: can buy nails ranging from twopenny up to sixtypenny in
Speaker 1: the United States, represented as two D or sixty D, respectively.
Speaker 1: When you buy a twopenny nail, what you're buying is
Speaker 1: a nail that is an inch long. A threepenny nail
Speaker 1: is an inch, and a quarter fourpenny is an inch
Speaker 1: and a half, and so on, increasing by quarter inches.
Speaker 1: That works up to a twelvepenny nail. So a twelvepenny
Speaker 1: nail is three and a quarter inches long, a sixteenpenny
Speaker 1: nail is three and a half inches long, a twenty
Speaker 1: penny is four inches, and after that there's the thirty, forty, fifty,
Speaker 1: and sixtypenny nails, each one a half inch longer than
Speaker 1: the last, So a sixty penny nail is six inches long.
Speaker 1: Why is D used instead of P when talking about
Speaker 1: pennies and nails? For example, a two D nail is
Speaker 1: a twopenny nail. It probably comes from the Roman coin
Speaker 1: called the denarius. It's not clear that anyone knows where
Speaker 1: the penny designation comes from, though it might have indicated
Speaker 1: the cost of a hundred nails of a given size
Speaker 1: in the four hundreds, but who knows. For more on
Speaker 1: this and thousands of other topics, is it how stuff
Speaker 1: works dot com