Luthier Tips du Jour Mailbag - Filing Fret Ends

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In this episode, Robbie O'Brien tackles a viewer's inquiry from Italy regarding frets that have become uneven with the edges of the fretboard, providing practical solutions and expert advice to address this common issue.

Video Transcription

[on-screen text reads: Luthier Tips Du Jour Mailbag]

Robert O'Brien: So, since I released my Luthier tips du jour video on humidity, I've been getting emails from all over the world from guys saying, I've got problems. What can I do [on-screen text reads:]? Well, the first thing you're going to notice when you have lack of humidity or too much humidity in your shop or your playing environment, is changes in action. The swelling or doming of the top, raising or lowering of the top will raise or lower the action. The next thing you're going to notice is probably fret ends sticking out past the edges of the fretboard. The third thing, and the more extreme cases are going to be cracks in the soundboard, in the backs, the sides, fretboard, things like that. The good news is that in the majority of the cases, it's strictly cosmetic. In extreme cases, it can be structural and you need to address that.

Mailbag Question: My fret ends are sticking out past the edges of the fretboard, what can I do?

So, today's Luthier tips du jour mailbag comes from Italy. Dear Robert, I know you told us to keep an eye on changes in humidity, but it was already too late. I'm a professional musician and have noticed that the fret ends are sticking out past the edges of the fretboard, making it uncomfortable while playing. What can I do? Please help, Stefano. Fortunately, there's a solution for this. Usually it's just running a file up and down the edges of the fret ends to make sure that they're flush with the sides of the fretboard. However, it can run into problems with the finish if you're not careful. So, let me show you how I would address this issue.

So, here's a guitar that came into the shop suffering from an extreme case of dryness. After we took the strings off, got it up on the rack, looking under the hood, we noticed that the fret ends were sticking out.

File fret ends flush with the side of the fretboard

We also have some structural issues to deal with and some cracking that's cosmetic. What I'm going to address here is the fret ends sticking out. So, I'm going to have to file those fret ends flush with the side of the fretboard. The very first thing I'm going to do is protect the soundboard. Since this is a harp guitar, I can protect it very easily on one side, but not very easily on the other side. So, the pucker factor is going to go up a little bit when I address this side. Now, to protect the soundboard, all I've done is just taped a piece of veneer over the top of it that allows me to come in with my file without running the risk of damaging the soundboard. So, with the soundboard protected, I then turn the guitar up on edge. I'm going to be using a fine flat bastard file.

Notice I have a smooth edge on one side. I'm going to place that towards the soundboard. As you're doing this, you have two things to be concerned about. First of all, don't damage the existing finish on the fretboard. Perhaps if you have a lacquer finish, the ends of the frets have already poked out the lacquer and you're going to have to do some finish repair. Second thing you want to be concerned about is down here by the nut. If you come down here, you could damage your peghead. So, you have to turn your file like this. So , I'm going to take the file in my hand, instead of running exactly 90 degrees with the side, I'm going to go just a little bit off the 90 degrees and come in and just lightly file the ends of those frets flush with the fretboard.

Up here [Robert points to the area above the fretboard next to the soundhole] I have the veneer protecting the soundboard. I'm also going to use my thumb and my index finger to keep from banging the soundboard.

[Robert works the file back and forth at an angle starting at the soundhole slowly working the file towards the peghead]

Knock off any sharp edges left from the file

And that's about all it takes to get them flush with the side. I also like to come in with some 320 grit sandpaper and a pad [Robert wraps the sandpaper around the pad to create a nice square edge], and very carefully knock off any sharp edges left from the file.

And you need to be extremely careful over your soundboard.

And I'm going to do exactly the same thing on the other side.

[Robert files down the fret edges on the other side of the fretboard]

I'm not 90 degrees. I'm a little bit off of 90, so I don't damage the finish.

Knock off any burrs

So now, all of the fret ends are flush with the side of the fretboard, but there's still more to do. One other thing I like to do after I've dressed the ends of the frets is come in with this little file here and just knock off any little burr that perhaps was left from the filing.

And obviously you'll need to do that on both sides of the fretboard.

Dress the frets and clean-up the fretboard

Once you've knocked off the burr, off the end, I like to come in with some steel wool, either the real stuff or the synthetic stuff, and just run it across the top of the fretboard. Make sure that everything's nice and smooth. It also dresses the frets just a little bit and cleans up the fretboard. Once you're done with that, the edges of the fret should be nice and smooth. They should not be poking out past the edge of the fretboard. They're flush with the size of the fretboard, and you're ready to go back out on tour. But hey, folks, don't let your instruments dry out. Humidity is very important.

Well, Stefano, I hope this information has helped. Remember folks, it's very important to keep your instruments humidified. Stefano, you were lucky. Perhaps next time you won't be, so make sure that you keep your instruments humidified.

[on-screen text reads: More Luthier Tips and online courses available at Private and small group guitar building and finishing instruction available]



Robbie O'Brien

Luthier and Instructor, Lutherie Academy