Brian's Guitar from Conception to Birth or How to Build a Guitar in 62 Easy Steps!
59 Dress the Frets
We’ve already worked on the neck, but we never really finished leveling out the frets. You can’t really do much until this point since it isn’t until now that you can string it up. Place a straight edge on top of the neck down the center of the fretboard. Adjust the truss rod so that it is as level as you can get it. Using a fat, black, permanent marker, draw a line on top of each fret being carefully not to mark on the wood. Grab your radiused sanding block you used to crown your neck, put on a fresh piece of 400 grit sandpaper, and lightly sand the frets in long, smooth strokes until you just sand off the marker lines. Don’t concentrate sanding in one spot; work the whole fretboard evenly. This will level the frets so they’re all in the same plane.
Once level, it’s time to re-crown the tops of the frets. Wipe off the sanding dust from the neck and tape off the wood leaving only the frets exposed. Understand that this will only provide a minor degree of protection; you will still need to be careful. Darken the frets with the permanent marker again. A fret crowning file specifically designed for this task makes the work quick and is only a small investment. File perfectly in line with the frets; I use my left finger to keep things on track. Work in long, smooth strokes and let the file do the work. Don’t go crazy filing on one fret or you will make that one lower than the rest; not good. File just until the marker line disappears. A few passes on each side with the file tilted at about a 45 degree angle will help make a smooth radius on top.
Once all the frets are crowned, it’s time to make them pretty with a few finishing touches. With a small piece of 600 grit sandpaper, remove any remaining file marks and finish rounding off the tops. This will provide a beautiful satin sheen to the frets. Using a flat needle file, remove any portion of the fret which hangs off the edge which might cause you to sever a finger. I used a thin piece of metal (cut from a soda can) to protect the side of the fretboard in case I filed too much. Switch to a fret dressing file which only has burrs on the sides and none on the bottom which could mar the wood. Gently file away any remaining sharp edges. We beveled the fret ends earlier, but recheck them to see if they need any additional touch up using a sanding block loaded up with 600 grit sandpaper. If your frets are happy with a satin sheen, stop here. But if you like the shiny gloss, install a buffing wheel on your Dremel tool and give it some polish. Just a few strokes will give you an amazing shine. Remove the tape and clean the fretboard with mineral spirits. Don’t worry, it won’t eat through the tung oil you put on earlier.