According to the different file density (that is, the number of main file lines per 10 mm length), files can be divided into 1, 2, 3, 4 and 5 files. Traditionally, 1 file grain is called coarse file (coarse teeth), No.2 file grain is medium file (medium teeth), No.3 file grain is fine file (fine teeth), No.4 file grain is double fine file, and No.5 file grain is smooth file.

Ordinary rough file is suitable for rough machining, medium file is suitable for ordinary machining, fine file is suitable for filing the surface of workpiece, and double fine file is suitable for finishing or polishing workpiece. However, when filing hard workpieces (such as tool steel), a thin file should be selected, otherwise the file teeth will be easily damaged; When filing soft workpieces (such as nonferrous metals), a coarse file should be used to avoid the file teeth being blocked by iron filings.

Extended data:

Precautions:

1, before using the file, check whether the file is in good condition and ensure that the file tensioning sleeve is moderately tight.

2, in the process of using the file should be handled with care, to prevent file fragments from breaking and hurting people.

3, it is forbidden to use a file as a hammer in the process of work.

4. In the process of filing, keep the file surface in smooth contact with the repair surface, and don't shake it from side to side, so as to avoid leaving too many deep file marks.

5. The advancing stroke of the file should be determined according to the size of the area to be repaired. Try to select a smaller file area while meeting the repair quality requirements.

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