Here's a question for youz guyz who know what you are talking about. I want to tap 1" x 11.5 NPT threads in a piece of brass. Looking at a man charts online for the proper drill size to prep the hole, I am given 1 5/32 - how can the hole be larger than the threads I want to cut? Everything else I've ever done has the drill being smaller than the tap - is there some magic to NPT? Thanks!