Making a bone nut?

[DWPC]

I'm surprised at how difficult it is to work a bone blank into a new nut. This stuff (obtained from a Spanish supplier) is really HARD! An hour of sanding hardly made a difference. Are there any tricks to working with it beyond patience and lots of 180 grit sandpaper?

[Stefan*]

I have a blank waiting for cutting ... so this answer will be appreciated by me as well.

I was thinking I'd get the dremel out.

[Zak]

It's my understanding that luthiers use some sort of files to do the job?

[MWA]

I start with a jig saw (power) to get it as close to the necessary size as possible. Then move to sandpaper of decreasing coarseness &/or files (I like to use files for the edges that must be very straight or flat). Then, use very fine steelwool (being careful not to round any edges) to get a slick finish. You can then get a mirror finish by using paint polishing compound or Brasso brass polish. Once the basic shape is set, there are files that are used to cut the slots for the strings. The slots should be no larger than the strings they hold and no deeper than necessary (some makers say 1/2 the string diameter). The slots should be cut so that all the string bottoms are on the same level over the frets.

[jeremy]

Bone is very hard, and if you do not have any power tools then you just have to sand it by hand. The most important thing with the nut is that the bottom surface is perfectly flat and that is contacts the neck without any gaps. Sanding by hand can tend to round the ends more than the middle. Put the sandpaper on a smooth flat surface, like a sheet of glass and hold the nut in the center. If you hold the ends you will apply more pressure to the ends than the middle and this will put a curve on the bottom face.

When you have the nut correctly fitting in the slot, it is time to cut the slots. Take a long pencil and cut or sand it in half lengthways, so the lead is visible along the length of the pencil. Place the nut in the slot, put the pencil on the frets with the tip against the nut, Move it sideways to draw a line on the nut. This line is the same height as the frets and this is where you cut your slots down to.

Measure and mark where you will cut your slots and then cut them with a very fine saw initially. Cut the slot at an angle from the front to the back. This angle should be about the same as the headstock angle. If you cut the slots flat ie in line with the fretboard, the strings will not break cleanly at the nut and you will get either a muted sound from the open strings, or buzzes or both. When you have the slot cut to depth, you need to file the slots to shape to suit the strings. Small round files work well but sandpaper wrapped around something the correct width will suffice. When this is done polish the slots with about 400-600 grit sandpaper. Try to take any sharp edges off the leading edge, but not remove any material at the same time. Sharp edges will cut into the nylon strings and break them. Remove too much material and you can cause tuning problems or rattles.

After you have fitted the strings correctly, then you need to trim down any excess in bone that is over the height of the strings. Some people like to see about 1/2 the string over the top of the nut, this is close enough.

After this is all done, it is time to polish the nut, Sand it with 600 grit sandpaper wet. If you do not have any polishing compounds, rub the nut on the palm of your hand and it will start to shine. If you want it to look old, put the nut in some strong tea. Sugar and milk not required.

Things to be careful of-
-Contact at the bottom of the nut and the neck .Very important!!!!!!!!!
-String spacing (leave about 3-4 mm for the treble E string to the edge)
-String height at the nut
-Smooth slots
-Angle of slot down to peghead

This whole subject gets a lot more complicated when you want to get into compensation for tuning, but for now, just get the nut made well. Then when you are confident, you can takle the next step.
________
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[rquinones27]

I just made one about 2 months ago for one of my guitars and I did it with a lot of patience and 180 grit paper as you said. It was hard on my fingers, but I accomplished what I wanted nonetheless. The Dremel idea could help out a lot, but the main thing is (if you don't have the right tools) to be careful and be patient.

[DWPC]

Great instructions, Jeremy. Thanks. Keeping all the surfaces square & flat is quite a challenge. I've a garage full of woodworking tools, but nothing really suitable for such fine work on such hard material.