What is the 16 U.S.F Threads meaning ?

USF UNF USS

1 Answer

What year is that drawing from? The only specs I find with a reference to USF threads are from the 1920's.

https://books.google.com/books?id=NohNAAAAYAAJ&pg=PA62&lpg=PA62&dq=u.s.f.+thread+standard&source=bl&ots=kMnCBdAuSG&sig=9kAd8JRuXNGd2Mf7slkgtsGSkZo&hl=en&sa=X&ved=2ahUKEwiU9qjEmbnfAhWhr1kKHcLUDBs4ChDoATAIegQIARAB

https://books.google.com/books?id=WL9CAAAAIAAJ&pg=PA164&lpg=PA164&dq=u.s.f.+thread+standard&source=bl&ots=CF3H4O154o&sig=nn0L0g8pgVGkCOk2BrFTC9uhNf8&hl=en&sa=X&ved=2ahUKEwiU9qjEmbnfAhWhr1kKHcLUDBs4ChDoATAAegQIChAB

If the drawing is referring to a "united states form" thread, it is an obsolete standard. Threads in the US are mostly Unified (fine or coarse), and even metric threads are becoming more common.