ClickSpring is a very interesting YouTube channel. Chris is a horologist, and experimental archaeologist located in Northern Australia. He recreates ancient tools which he uses to build ancient machines. In this episode he makes metal files like they would have been made c.100 BC. The shops were such tooling was made in antiquity have been excavated the tooling used to make files has been found. He uses natural sharpening stones. There are several episodes where he makes files. His metal shaving and filing tools would be very useful work on a knife blade.
