Martin: New Bone Nut


1. A Martin Guitar. This one is a Model M-38. This guitar needed a refret and a new nut to make up for the added fret height.	2. A Repaired Nut. This nut had been repaired previously. The slots had been filled with super glue and bone dust (or baking soda?). This alone would qualify the guitar as a candidate for a new nut.


3. Removing the Old Nut I scored the finish around the nut to prevent chipping of the finish, then fractured the glue joint with a light tap of a mallet. Now I'm carefully pulling it free with flush-ground end-nippers.	4. Removing the Old Glue from the end of the fretboard is quick and painless with a razor-sharp chisel. It is imperative that none of the the fretboard be removed.


5. Sanding the Nut Blank square on two sides is the first step of shaping the nut blank. I'm achieving this with 80 grit sand- paper on a dead flat granite slab. A squared piece of steel makes a good fence to keep everything square.	6. Thickness Sanding the Bone Nut Blank is really fast with the "Luthier's Friend Precision Sanding Station".


7. Angling the Nut Bottom with the disc-sander bed angled to 16 degrees.	8. Truing the Nut Bottom with an angled sanding block with self-adhesive sandpaper.


9. Preparing the Nut Seat is necessary as the seat must be flat and free of old glue. Fine grit self-adhesive sanding paper affixed to the bottom of the new nut does a fine job of preparing the nut seat. I am only lightly sanding the neck, not the end of the fretboard.	10. Shaping the End of the Nut with the disc of the shop's belt sander. Because the layout line I traced on the end of the nut is not square (it never is) I'm slightly tilting the blank on the disc sander's bed so the abrasive disc removes only the material I want it to.


11. Final Shaping of the End of the Nut with 1000 grit sandpaper on the shop's dead-flat granite slab will remove all of the disc sander marks. I'm genly rocking the nut as I sand as I fine tune the fit between the end of the nut and the neck/fretboard.	12. Laying out the Height of the Nut. A Pencil ripped in half laying on the frets gives me a good line to sand and file to.


13. Shaping the Top of the Nut using the shop's disc-sander. I've adjusted the sander's bed to 6 degrees which is just about half the average string break angle I'll want for the strings as they lay accross the completed nut. With the disc- sander I'll sand away the excess bone from the top of the nut to just shy of the pencil line on the bass side and just into the line on the treble side. This will give the completed nut proper string protrusion.	14. Contouring the Top of the Nut with fine grit sandpaper both gives the nut a traditional Martin nut profile and removes the sanding marks left by the disc-sander.


15. Polishing the Nut with the shop's small buffing wheels gets the bone as smooth and glossy as glass. I load the coarser wheel with jewler's rouge and do the final cleaning and polishing with the clean and compound free, fine wheel.	16. Establishing the Outer Nut Slots. With the E strings temporarily in place, I can ensure the nut slots work lateraly with the neck set and fret ends.


17. Notching the Outside Slots. I used a fine tip marker to layout the 1st and 6th strings. Now I'm notch the nut with a .016" nut slotting file at those marks..	18. Laying Out the Inner Slots. I'm using this handy tool sold by Stew Mac. It compensates for the gradual increase in diameter from string to string to ensure an even feel.


19. Final Slotting of the Nut. I use a small metal hook to elevate each string above the nut as I fine tune the nut slots. I established each nut slot with a fine slotting file, now I'm dialing them in with the Proper sized file for each slot.	20. Flossing the Nut Slots with abrasive cord gets rid of the unwanted file marks that can interfere with tuning stability.


21. A New Bone Nut looks pretty smart and has helped stabalize this guitar's tuning stability.	22. Feel and Playability are obviously important factors to keep in mind when cutting a new bone nut. The sides of the nut are flush with the side of the neck end finely polished for a comfortable feel.