The nut is tightly linking the mechanical equipment parts, threaded through the inside, the same kinds of nuts and screws to connect together, such as the M4-0.7 nut only screw with M4-0.7 (nut, M4 refers tonut inner diameter of about 4mm, 0.7 refers to a distance of 0.7 mm between the two screw thread); US-made products are also, for example, a 1/4-20 nut with a (1/4 refers only with 1/4-20 screwThe nut inside diameter is about 0.25 inches, 20 refers to every inch of the 20 teeth).

 

Square Nuts