Non-standard screw nut refers to the structure, size, drawing, marking and other aspects have been fully standardized, and by the professional factory production of commonly used zero (part) parts, such as screws, keys, pins, rolling bearings and so on. The non-standard screw nut is mainly the country that has not set strict standard specifications, and there are no other related parameters, and other accessories freely controlled by the company. There are many varieties of non-standard screw nuts, and there is no very standard classification.
At present, there are two kinds of non-standard screw nuts, one is iron, that is, carbon steel. One is stainless steel, of course, copper, aluminum nuts, but these are less used. Copper is still useful, and aluminum nuts are rarely used. Non-standard screw nuts are often used in applications that require frequent assembly and disassembly, or are often used where the surface space of connected components is limited.