NormanB,
My apologies sir as I did not man to offend any wacky Englishmen (women), in my haste I displayed only my own ignorance.
Senior Member Status - rest assured that I know more than anyone else that it is much more a measure of all that I do not know than any little bit that I might think I do know. More questions than answers in the total of all posts!!!!!
Lastly the described tool's proper name would be a Thread Pitch Gage or a Screw Thread Pitch Gage.