⒈It is not allowed to use new files to frustrate hard metals;
⒉It is not allowed to use files to frustrate quenching materials;
⒊Forgings and castings with hard skin or sticky sand, they must be ground off on a grinder before they can be filed with a semi-sharp file;
⒋Use one side of the new file first, and then use the other side when the side is blunt.
⒌When filing, always use a wire brush to remove the swarf on the teeth of the file.
⒍Files cannot be overlapped or stacked with other tools;
⒎It is not advisable to use the file too fast, otherwise it is easy to wear prematurely.
⒏The file should avoid water, oil or other dirt;
⒐Fine files are not allowed to file soft metals;
⒑Using assorted files should not be too strong to avoid breaking.
