Page 1359 in the 20th edition, Square Thread.
The square form of thread has a pitch about twice that of Unified threads.
...largely replaced by the Acme form of thread...
Pages 1708-1709 have an explaintaion and chart for making the taps.
"Wildfires are dangerous, hard to control, and economically catastrophic."
"Fixed in the next release" should replace "Product First" as the PTC slogan.
Ben Loosli
CAD/CAM System Analyst
Ingersoll-Rand