The types of file can be divided into flat file, square file, triangular file, semi-circular file, round file, diamond file, knife file and so on according to the shape of the knife surface. If classified by file style, it can be divided into single file and double file; If files are classified according to their uses, they can be divided into: ordinary locksmith files, wooden files, plastic files, saw files and special files.

Brief introduction of file surface shape

Flat file: used for filing flat and convex surfaces. Square file: used to file grooves and square holes. Triangular file: used for filing internal corner surfaces and grooves larger than 60. Used for filing concave curved surfaces, large round holes and facets. Circular file: used to file round holes and small radius surfaces.

Brief introduction of documents

The file is made of carbon tool steel T 12/ 13 and hardened by heat treatment. File consists of file body length, file surface, file edge and file tongue. When using files, you should install file handles. The file handle is usually made of wood or plastic, and the end of the wood file handle is equipped with an iron hoop to prevent it from breaking. The tooth line of the file is mostly made into double lines, and its thickness specification is expressed by the number of main file lines per 10mm in the file length, which is divided into 1, 2, 3 and 4 lines.

The earliest appearance of documents

The earliest documentary records in the world originated from Greek literature. According to records, the Crete civilization in Greece invented bronze file around 2000 BC, the earliest copper file was invented by the ancient Egyptians in 1300 BC, and the iron file was invented around 700 BC.