If you are building your own guitar, one of the most important steps is making the nut and saddle.
Close attention to detail is necessary to not only make a good looking nut and saddle
but to also make your guitar playable.
If you carefully follow my instructions here you should be able to make a nut and saddle
for the guitar you are building or replace a nut or saddle on an existing guitar.
The first step for making the nut
is to make sure that the nut slot is free of all excess glue and debris.
I use a narrow chisel to clean up this area.
You could also use a file.
Notice how my file has one edge sanded smooth.
This way I keep the bottom of the slot flat.
Next I need to thickness the bone nut blank to the thickness of the slot.
You can do this by hand using sandpaper.
I use about 150 grit paper and turn the bone around often while sanding
so that it stays as square to the original shape as possible.
As the nut blank gets closer to the actual thickness needed
I switch to 220 grit and then finish with 320.
A quicker way of doing this is to use a thickness sander.
You could also use a spindle sander with a fence clamped to the table.
I still do some hand sanding with the 220 and 320 grit paper though
to remove any course sanding marks.
Now place the nut in the slot and make it flush with one side of the fretboard.
Use a half pencil like the one I am showing here to mark the correct width
on the other side of the nut where it meets the fretboard and transitions into the peghead.
You can use a small saw to cut the nut to width.
I leave a little excess and then bump the edge on my disc sander to get the correct width.
Carefully clean up the edges with finer grit sandpaper to remove the course sanding marks.
Notice how the nut fits perfectly in the slot and is flush on the ends.
With the nut placed completely into the nut slot,
use the half pencil placed across the top of the frets
to draw a line on the front side of the nut.
Using the half pencil allows you to place the line at the exact height of the frets.
On my steel string and electric guitars the fretboard is radiused.
Using this technique allows you to trace this radius
on the front edge of the nut at the correct height.
I now sand the top of the nut until I am about 1/32nd above the line on the nut.
You can do this by hand or on a disc sander.
Be careful not to give yourself a manicure if using a disc sander.
Here is a cool jig that has grooves cut in it at certain depths.
This allows you to quickly mark the correct amount to remove without having to measure.
The next thing I do is round over the back side of the nut.
I usually do this with a file but you could also just use sandpaper.
I start with a course grit and sand up to about 320 or even 400 grit.
I also like to slightly round over or soften the very ends of the top side of the nut.
Now it is time to slot the nut.
I start by marking the string width according to my plans or the client’s particular taste.
Then I divide this to get even string spacing.
When slotting the nut for the strings on my classical guitars
I like to have the strings 1/32nd or .8mm above the frets.
There is an easy way to do this.
I use a scraper that is exactly this thickness
and place it on top of the frets and push it up against the nut.
I put a piece of tape on it to hold it in place.
This technique doesn’t work for guitars with radiused fretboard
so I set the string height on those guitars when doing the set up.
I like to protect the peghead area by placing a piece of tape over it.
I then use a small exacto saw to begin slotting the nut for each string.
Notice the angle of my cut is the same as the peghead angle.
I am only starting the slot.
I am not worried about cutting to the correct depth at this point.
On the back of your package of strings there is a chart
with string diameters in inches and millimeters.
You will need a set of quality nut files for this next step.
Choose the nut file that corresponds to the correct string diameter for each string
and use it to file the slot.
Continue until the file just hits the scraper that you placed over the frets.
This will set each slot to the correct depth.
Ideally the strings should be about half in and half out of the nut.
Adjust the nut height accordingly if necessary.
Continue filing until all the slots are at the correct depth.
Now I sand the nut up to about 1000 and since I am serious about my nuts,
I give them a quick buffing on the buffing wheel to make them nice and shiny.
After the set up is all done I place a small drop of white glue
or even CA glue on the front edge of the nut to hold it in position.
Now that the nut is done I can begin working on the saddle.
Just like nut, the saddle also has to be thicknessed so that it fits in the saddle slot.
You can do this by hand with sandpaper or use a power sander.
Even if I use a power sander I only get it close
and then finish by hand so that it fits snuggly in the slot.
You want to have it snug enough that you can turn the guitar over
without it falling out but you should be able to remove it easily when needed.
On my steel string guitars
I now also make the saddle the correct width and round the ends so that it fits in the slot.
I also place it against the end of the fretboard
so I can trace the radius of the fretboard on to it using the half pencil.
To make the saddle the correct height we need to check the action at the 12th fret.
This is the height of the string above the fret.
You can measure this with a ruler
or place a shim with the correct measurement at the 12th fret.
Use the half pencil to mark the place where the ruler hits the saddle.
Do this for the 6th string and the 1st string.
Use a straightedge to connect these lines then sand down to this line.
If you have a radiused saddle then use the radius line you drew on the saddle
as a guide to put the same radius on the saddle that you have on the fretboard.
The next step is to round over the back of the saddle
so the break angle is on the leading edge.
On open ended saddle slots like on classical guitars
you can now cut or sand the saddle to width.
I then remove all sharp edges by sanding up to at least 320 grit.
Like so many other aspects of guitar building,
a lot of things have to have been done right up to this point.
Learning how to correctly make a nut and saddle is just one more step in a long chain of events
that must be done right in order to have a playable guitar.
With the information I have provided this should be no problem.