Sometimes we get guitar necks in the shop that have, well… some problems. It doesn’t matter if it’s new or used, expensive or cheap, vintage or modern: bad necks come from all eras and price points. Some necks are twisted and warped, which causes the frets to be extremely uneven all the way up the neck. Sometimes leveling the frets will make up for the inconsistencies in the neck; sometimes the entire neck needs to be re-fretted. It’s impossible to see how a neck reacts to string tension and truss rod adjustments until we put it on our neck jig and see what the dial indicators have to say. Severely warped necks can have their frets leveled down to almost nothing in certain areas while remaining tall in others (like when a neck has a huge dip in the middle and a rise near the heel). Usually on these necks we recommend a re-fret, but some customers choose not to do this for a number of reasons, so we have no choice but to mow ’em down. As long as the fret isn’t leveled all the way down to the fingerboard, they will still play clean, but it’s certainly not ideal.
We did a fret level on a bass neck that had a HUGE bump in the heel right where the neck joins the body, and had no choice but to grind the last few frets down to almost nothing (the customer didn’t want to re-fret this one). When the frets are leveled, they need to be re-crowned to put them back to a nice round shape; we typically use a Stew-Mac diamond grit fret file to do this job. This time, however, the frets were so close to the board that the rounded file wouldn’t touch the fret tops before it hit the poly finish, so we reached for a tool we rarely use for fret crowning: our customized triangle file:
This tool takes a much higher degree of skill and patience to use. Each fret is carefully filed, taking off just enough to round the fret without taking any off the centerline, which would compromise the fret level.