Is the thread of a vice with a zigzag thread
Today, the vice screw of the bench in our factory was wrung, so I had to draw one, and then my own car, and I paid attention to his threads: the zigzag thread!
So don't generalize! The truth is the combination of theory.I hope my answer will help you
Inside is a t-nut, the letter "Tr". It is usually 4-6 pressure, single thread nut