Re-crown

Restoring the rounded profile of a fret's top after levelling has flattened it, using a shaped file followed by polishing.

A flat-topped fret gives poor contact with the string, so notes sound dull and intonation suffers slightly, and the extra surface area also makes the string feel scratchy. Crowning removes metal from the shoulders of the fret until only a narrow strip at the top touches the string, keeping the level plane that levelling produced. It is a job that removes material from the frets, so it can only be repeated a limited number of times before refretting is needed.

Example: after levelling a neck with a slight hump, re-crowning and polishing are what make the notes ring cleanly rather than dully.

Re-crown

See also