The nut and the saddle are the two contact points at either end of the vibrating string. Every note the guitar makes passes through both of them, and both of them are small enough to be an afterthought. They should not be.
A nut cut badly makes the guitar hard to play at the first fret and impossible to tune cleanly. A saddle set badly makes the action wrong and the intonation worse. Neither is expensive to fix, and both are frequently wrong on new instruments.
Nut materials
- Bone: the traditional choice. Hard, dense, transfers energy well, and it cuts cleanly with a good file. The standard for anything serious.
- Synthetic ivory and polymer composites: consistent, easy to work, and close to bone in tone. Popular because they are uniform and animal-free.
- Corian and similar solid-surface material: hard and bright, easy to find, and works well enough for a repair.
- Brass and metal: bright and loud, with a distinctive metallic edge. Rare outside specialist instruments.
- Plastic: soft, dull, and it wears under the strings. If a nut is plastic, replacing it with bone is one of the cheapest upgrades available.
Saddle materials
The saddle is the bridge-side contact point, and it has a larger effect on tone than the nut because it sits on the soundboard and passes vibration directly into it.
Bone is again the default. Ivory was traditional and is now unavailable. Synthetic materials are consistent and predictable. Some builders use a harder material for a brighter sound or a softer one for warmth — but the difference between a well-fitted bone saddle and a well-fitted synthetic one is smaller than the difference between either and a badly fitted one of any material.
A saddle that does not sit flat in its slot loses contact with the bridge and kills the transfer of energy. Before you change the material, make sure the saddle is flat on the bottom and seated fully.
Setting the nut height
Set the relief and level the frets first
Nut height is measured against the frets, so the frets have to be right before the nut means anything.
Check the current clearance
Press each string at the third fret and look at the gap between the string and the first fret. It should be barely visible.
File the slot down
Use the nut file matched to the string gauge. A few strokes, then test again.
Angle the slot toward the headstock
The string should break cleanly over the front edge of the nut, not sit in a flat-bottomed trough.
Lubricate
A little graphite or nut lubricant stops the string sticking and wandering out of tune.
Setting the saddle height
Saddle height sets the action at the twelfth fret. The relationship is roughly two to one: lowering the saddle by 1 mm lowers the action at the twelfth fret by about 0.5 mm, because the twelfth fret is roughly halfway along the string.
Lower the saddle by sanding its bottom, not its top. Sanding the bottom keeps the top profile — and the intonation compensation cut into it — intact. Sand on a flat surface with the saddle held square, and check it against a straightedge as you go.
| Fault | Symptom | Cause |
|---|---|---|
| Nut too high | Hard to press near the nut; notes sharp | Slots not cut deep enough |
| Nut too low | Buzz on open strings only | Slots cut too deep |
| Slot too narrow | Tuning drifts; pinging sound | Wrong file for the gauge |
| Saddle not seated | Thin, weak tone | Saddle bottom not flat |
| Saddle too low | Buzzes when played hard | Action below the instrument’s limit |
The nut and the saddle are where the string stops being a string and starts being a guitar. Get them right and the rest of the setup gets easier.
