Sharpening flat graver with Lindsay flat & knife combo sharpener.
System consists of 2 templates. 1st is smaller one, which is used for initial shaping of graver. With that you also determine the width of the graver, up to a sharp knife edge.
2nd and bigger template is used to grind the face of graver and to make a heel. When graver tip breaks during engraving, then this template is usually all that is needed to sharpen it again. 30 seconds and done.