Martin DM: New Bone Nut

Related Topics: | Nut | Saddle | Set Up | Truss Rod | Martin DM: Bridge Reglue | Martin DM: Compression Refret |


1. A Corian Nut. I'll be replacing this guitar's stock corian nut with a bone one. The nut must be replaced because I've just refretted this guitar. Taller frets necesitate a taller nut. I'm making the new nut from bone because a bone nut will last longer and (arguably) sound better as bone is a tough, dense material.	2. Scoring the Lacquer around the nut will allow me to remove the nut without chipping the finish.


3. Loosening the Nut is done by gently tapping a block of wood against the nut. This is a delicate operation as excessive force could damage the faceplate's finish.	4. Removing the Nut with a flush cutting pair of large end-nippers is done with great care to insure that the finish around the nut sustains no damage.


5. A Clean Extraction is the result of careful preparation and patience.	6. A Bone Nut Blank. This nut blank is made from bleached cow bone. I've squared two surfaces with one another on a granite slab with 600 grit sandpaper and marked these surfaces with an X. These two surfaces will become the bottom and fretboard-side of the nut.


7. Rough Sanding the Blank to thickness is a quick affair while using the belt sander. I frequently check my progress with the calipers to insure that I don't remove too much stock on the belt sander. I'll leave the blank a bit proud so that removing the course sanding marks and polishing the bone don't make the blank too thin.	8. Marking the End of the Nut with a pencil gives me a good layout for rough grinding the end of the blank. I'll mark all three surfaces of the nut that make contact with the nut seat.


9. Grinding the End of the Nut on the belt sander works pretty well. I've found that the ends of a nut are never quite square. This so happens to be the case with this contemporary Martin. The thin piece of wood under the end of the nut is acting as a shim to help me grind the proper angle into the end of the nut.	10. Filing the End of the Nut with a Swiss-needle file will get rid of the course belt sander marks, as well as begin the process of final shaping of the end of the nut.


11. Sanding the End of the Nut on a ruberized cork lined block removes the file marks from the bone. Since the cork compresses beneath the downward pressure of the blank as it passes over the sandpaper (in circular motions) the edges become ever-so slightly rounded. This will create a smooth feeling transition from wood to bone as the player's hand passes over the ends of the nut. I'm sanding with P-800 grit sandpaper.	12. Polishing the End of the Nut. I like to do this with micro-mesh sanding pads. I use these fine abrasives up to 12,000 grit. I'll repeat this process of shaping the end of the nut for the opposite end before laying out the nut's height.


13. Laying out the Height of the Nut. A Pencil ripped in half laying on the frets gives me a good line to file and sand to.	14. Filing the Nut to Height. I prefer to leave a bit of excess material over the line at the 6th string and file to just under the line at the 1st string . Filing the top of the nut in this fashion will result in the ideal final string protrusion (the amount of each string protruding above the top of the nut).


15. Contouring the Top of the Nut. I'm frequently checking my work to insure that I'm accurately replicating the contour of this guitar's original corian nut.	16. Rounding Over the Ends of the Nut. Again, I'm using a Swiss- needle file as it is just the right size and cuts rather lightly.


17. Finish Sanding the Top of the Nut with 600 grit sandpaper in the bench top vice will leave an even surface for the process of pol- ishing the nut.	18. Polishing the Top of the Nut with the full set of micro-mesh abrasive pads (2400-1200 grit) is a quick affair that leaves excellent results.


19. Laying out the Nut for Slotting. I'm using this handy tool sold by Stew Mac. It compensates for the gradual increase in diameter from string to string to insure an even feel.	20. Slotting the Nut. I'm only rough slotting the depth. I'll restring the guitar and make my final cuts in a minute. First, notice the angle of the slotting file. It's halfway between the plane of the fretboard and the plane between the E string tuner post's hole and the bottom of the nut slot. This insures that I'll have full string contact accross the bottom of the nut slot.


21. Checking the Depth of the Nut Slots is done by depressing the string inbetween the 2nd and 3rd fret and measuring the space between the top of the 1st fret and the bottom of the string. As the strings' diameters increase, so does the gap between the string and the first fret.	22. Final Depth Adjustment of the Nut Slots is done with the aid of a rounded, metal hook. The hook safely elevates the string above the nut giving me free access to file the slot.


23. Lubricating the Nut Slots occurs after they are cut to their final depth. I prefer to use extra fine powder graphite. Although a pencil also serves the same purpose I am scepticle of the binders used in pencil lead. I wrote a major pencil manufacturer regarding the corrosive effects of their lead binders and was unable to assertain said content. Their formula is proprietary.	24. With a New Bone Nut, new bone saddle, bridge reglue and compression refret, this guitar is at the top of its game!