One, screw

The screw is the use of the object’s beveled circular rotation and friction of physics and mathematical principles, step by step fastening tools.

Screw is the general term of fasteners, the daily language.Screw is generally said to be an indispensable industrial necessities in daily life: such as cameras, glasses, clocks, electronics and other use of small screws;General screws for TV, electrical products, Musical Instruments, furniture, etc.As for engineering, construction and bridge, large screws, screws and nuts are used.Transportation equipment, aircraft, trams, cars and so on for the size of the screw.

Screw has an important role in industry, so long as there is industrial production on the earth, the role of the screw is forever.Screw is one of the great inventions of human beings, which has brought convenience to people’s production and life for thousands of years.

Two, standard parts

Standard part refers to the structure, size, drawing, marking and other aspects have been completely standardized, and by the professional factory production of common zero (part) parts, such as screw parts, keys, pins, rolling bearings and so on. 

In a broad sense, it includes standardized fasteners, connectors, transmission parts, seals, hydraulic components, pneumatic components, bearings, springs and other mechanical parts.In the narrow sense, only standardized fasteners are included. 

The domestic commonly known standard part is the abbreviation of the standard fastener, is a narrow concept, but can not exclude the existence of the broad concept.In addition, there are industry standard parts, such as automobile standard parts, mold standard parts, hydraulic standard parts, construction machinery, etc., also belong to the generalized standard parts.