Pipe thread is not equal to pipe thread - Threading tools guide | GSR Blog
Threading formulas and definitions
How To Identify British Pipe Threads - V-Flow Solutions
Practical example: 3 steps for thread determination (1/4" inch)
BA & ME Threads
STEENBEEK Magnetic Mount 66 mm + 88 mm Set 1/4 Inch Internal Thread Mount Set for Smartphone Actioncam DSLR Video Camera (Combi Set 1, 66) : Amazon.co.uk: Electronics & Photo
Thread Chart (UNF-UNC) | Major and Minor Diameters