Fine teeth file, hard materials with coarse teeth will cause great damage to the file, so fine teeth file should be used. The amount of filing each time is small, but the damage to the file is small. The file is made of carbon tool steel T12 or T13 after heat treatment and then quenching the working part. There are many fine teeth on the surface, which are hand tools for filing workpieces. The application of file is very early. The oldest file that has been found is the bronze file made in Egypt around 1500 BC. Modern files are generally made of carbon steel through rolling, forging, annealing, grinding, tooth cutting and quenching.
