The Hippie Gets a New Nut!
My '68 FG150 is a special guitar. I purchased it several years ago for about $100 on eBay. My first acoustic guitar was a '71 Yamaha FG140 Red Label so this guitar filled my nostalgic need as well as being an excellent beater guitar for campfire duty. My wife calls it "the hippie guitar" because is so obviously travelled and played.
When I bought it, it required a neck reset and a refret. When I took my guitar technician training with Miles Jones three summers ago, the hippie guitar was a good candidate for my first neck reset. I did a photo essay on the training, the neck reset and the refret that was posted on the Larrivee Forum. I put a new bone nut in the guitar at the time but never replaced the original nut which I would assume is some form of Corian or Micarta. The original has very wide slots and has yellowed substantially with age.
Here is "Hippie" with the strings coiled and the truss rod cover removed.
Old Nut
First thing to do when removing a nut from an acoustic guitar is to break the finish between the nut and the headstock. Hippie didn't have any finish here but this photo illustrates the procedure. Simple score the groove behind the nut so when you tap the nut out, you don't take wood or finish off the headstock. Then tap the fretboard side of the nut with a hammer and a piece of hardwood and a mallet. In this case, I used the bone blank I used for the new nut.
Scoring the Nut Edge
Tapping Out the Old Nut
Nut Removed
If the nut was glued in correctly it should just pop off. The nut is supposed to be glued to the end of the freboard and not to the bottom of the nut slot. If your nut has been glued in by someone who never wanted it removed, you might have to collapse the nut in on itself and chisel the whole thing out. With a small toothed saw like a small hacksaw, cut a groove along the length of the nut. Then use pliers to squeeze the two halves together and collapse the nut in on itself. Then some work with a sharp chisel should get out any remnants. For the Yamaha, the nut popped right off cleanly. I used a sharp chisel to remove any glue residue from the end of the fingerboard.
Removing Glue Residue From Fingerboard End
I then took the bone nut blank and cut it to the appropriate length using the original as a guide. After clamping a piece of 150 grit sandpaper to my flat piece of marble. Continually comparing the original nut to the blank, I rounded and shaped the nut blank by eye. The slant of the top of the nut was particularly important. I had to be careful not to lose any height as I rounded the top in a gentle curve back towards the headstock.
150 Grit On Marble Slab
Shaped Blank
At this point a new string spacing could be worked out and penciled on the top of the nut. Stew-Mac has an excellent string spacing guide. However, I was happy with the spacing on this 1 11/16" nut so I simply transfered the string locations from the old nut to the new one.
Marking String Spacing
With the new nut shaped and in place, I prepared the nut files I would use for the slots. In the photo, you'll see I've listed the string gauges from a set of Light Elixirs (.012, .016, .024, .032, . 042, .053) and the closest file I have to those string diameters below (.012, .017, .028, . 034, .046, .052). I started all six slots with the .012 file. When working on nut slots, it is important to angle the file towards the headstock so the file matches the break angle of the headstock with respect to the fretboard. This backwards slope will allow the string to bear on the leading edge of the nut facing the fretboard. I put two or three layers of masking tape over the fretboard and the headstock to protect them from slips of the file. The nut is NOT glue in at this time!
Nut Files
Fretboard and Headstock Masked
Starting the Nut Slots
Once the nut slots are started, the strings can be lifted into place. The strings will hold the nut in place while working on one string at a time. Starting with the high E string, the string is slipped off the nut slot and the slot filed a little at a time. Once some material is removed, the string is slipped back into the slot and checked. Checking the appropriate action of the nut is simple; tune the string to pitch and press down on the string at the third fret. This basically makes the string between the third fret and the nut a straight-edge. With a high nut slot, the string will display a gap between the bottom of the string and the first fret crown. I will file the nut slot until that gap is a mere hair's width. You can test the gap (because it is so tiny) by tapping on the top of the string over the fret. You should hear a small metallic "tink" sound. If the string rests on the first fret, you've filed the slot too low. So it is vital to work slowly! If you don't want to check by eye or feel, use a feeler gauge to get the right thickness.
Checking the Nut Action With a Feeler Gauge
Once all the nut slots were correctly grooved, I removed the nut and sanded the top and headstock facing edge with 600 grit paper and then buffed it with my Dremel Tool and some Meguiar's Scratch X on the buffing wheel. This polished the nut up beautifully. I buffed the fretboard face of the nut a little but was careful not to disturb the leading edge of the nut slots or the bottom of the nut.
The slots for the high E and the B strings are a little deep in the nut although the action is perfect there. This means I didn't get the top radius of the nut exactly correct. I can fix this by gently sanding the top of the nut on that side so the strings will sit proud of the nut slot by about half the thickness of the strings.
Finished result:













