If you want to understand how to determine a bolt or nut thread size then you need to read this article by RCF Bolt & Nut.
Bolt Size Chart, UNF Bolts, UNC Bolts
Experimental and numerical studies of bolted T-stub steel connection with different flange thicknesses connected to a rigid base - ScienceDirect
Determining Bolt & Nut thread sizes by RCF Bolt & Nut
/wp-content/uploads/2020/06/pitch.j
TDC 6 388, PDF, Nut (Hardware)
Bolt Size Chart Bolt Dimensions, Thread, How to measure Bolt Size?
/media/cache/attachment/filter/wysiw
/media/cache/attachment/filter/wysiw
/media/cache/attachment/filter/wysiw
/media/cache/attachment/filter/wysiw
How to Determine Bolt Thread Size - Bolt Threads Strength & Design