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Scalloping the guitar fretboard - possibly also renovation of the instrument

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I have an old electric guitar, that has been gathering dust for years, because of its condition. It was never in particularly good shape, even when I bought it decades ago.

On the other hand, it has a quite good neck(maple and rosewood), but uneven frets are what makes it not so pleasant to play. So it is a perfect candidate to practice fretwork techniques, like leveling and crowning.

But first comes the scalloping, even though I'm not sure what the outcome will be. Although there are lots of videos about it in the Youtube, I'm going to find my way to do it.

What is the fretboard scalloping anyways? Basically it's just removing wood from the fretboard. Ordinary one:

And same after scalloping:


What has kept me from doing it in the past, is that the depth of the wood removal needs to be somewhat shallow, and consistent through the whole fretboard. That way the neck's rigidity shouldn't be weakened too much.

Some testing, by filing about 1mm from the fretboard surface:


Different filing jigs were already tried, this being the latest:


It was printed, as machining that kind of piece would require enormous amount of work. Next to the file, there is a groove for the fret, that acts as a guide, so that the frets themself don't get filed.

On the opposite side is just a flat surface, that rubs over the fretboards surface, once the file doesn't 'bite' anymore. Different sizes/forms need to be printed, as the scalloping goes on.

Of course I could use Dremel to make the wood removal faster, but it would require way too complex jigs. Besides, I don't fancy having any kind of wood dust floating around in the air.

Next thing to do, is to use the above filing jig for rest of the fretboard.


At the most basic level, the position of a fret is the string length/17.835.  [In "pure harmonics," a distance of string length/18 raises the pitch one half-note.  The "17.865" value accounts for the incrrease in string tension created by fretting.]  Obviously you will have to account for the width of your fret wire in determining your "scallop" and reduce the "17.835" value to account for the added tension.  --  Lew

Lew, thanks for the info. But the fretboard itself isn't part of the note-producing process, except on fretless instruments, like violin, contrabass, and such(in form of fingerboard).

In fact, on fretted instruments like guitar, the fretboard might not be necessary at all. Gittler guitar:

So the scalloped fretboard is one way to add a bit more freedom to the playing. It requires lighter touch, because it's easy to do unintentional 'microbends', just by pressing the string, as there is no wood close to the pressing finger, like on ordinary 'flat' fretboard. Also string bending is a lot easier, when the finger(s) don't rub against fretboard.

Project goes on. More filing:


Side markers are falling out, but I don't need them anyway.

Plan is to remove 0,5mm more by filing, and after that, plenty of sanding. It actually feels good to use some elbow grease, after previous electronics projects.

OK, if you take a "string" and tension it over two (separated) "edges" & "plug it," it will vibrate at a given frequency based on: tensioning force, shear modulus, and plucking duration.  Shorten the "separated edges" distance by 1/18'th and, maintaining the other "variables," pluck it with the same force & duration and the "note" played by the "string" will be on half-tone higher than the previous one.  However, when you "dish our between the frets you are changing the tension within the "string."  [My original Journeyman's rating is Luthier.]  --  Lew

Yeah, there are plenty of things involved with strings, and frets.

Again, more filing. Arched scallops would look better. Instead the result is more like 'U-channels'. That is fine by me, as the filing fixtures seem to work well:


Bit of rounding on the areas near to the frets, which might not be necessary, but to get completely rid of that awful, glossy finish(lacquer/varnish perhaps), that the fretboard had in its previous life.

Fret markers needs to be redone, maybe using bigger, Fender-style dots. They have to be shallow, as there isn't much of wood left, and I don't like to hit the truss rod with a drill bit. But we'll see.

To go ahead of myself, if all goes well, I'm going to dye the fretboard as black as I can, and finally, apply several layers of matte lacquer to it.

Before that, after the scalloping is done, resulting fretwork dictates, if it's worth the effort.   


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