Diamond Fret Levelling File

When frets are installed into a fingerboard they are never completely straight even if great care was taken in installing them. Therefore the frets must be levelled or 'dressed' so that they are straight and the guitar will play with minimal fret buzz.

The fret levelling file is rubbed over the tops of all of the frets to grind down the high frets until they are level with the low frets. Long oval-shaped strokes will give a more even result than a straight up and down action.

You can tell when the frets are level when the tops of every fret are scratched from the file the whole way across. It is handy to draw a line across the top of every fret with a back permanent marker pen, so you can see when the levelling file has scratched the top surface.

Once the frets have been levelled they need to be crowned so that they have a nice round profile on top so the strings will play clean and in tune. A fret file has a concave edge which is exactly the right profile to shape the tops of the frets back into this curved shape.

The fret is rubbed with the fret file until it is rounded off. It is a good practice to leave a very narrow flat-spot on the top of the frets to ensure you don't go to far with crowning them. After crowning with the fret file various grades of sandpaper and steel wool are used to polish the fret. The fingerboard should be taped or a fingerboard guard used to avoid scratching the fingerboard.