Nuts, why higher?

[Kinda Old]

I know there needs to be a nut on a guitar to hold the strings in place. But why does it have to be a bit higher than the frets? It makes chords at the top of the neck harder to play, especially F (barred)
Is there a good physical reason that the nut can't be fret high? I sometimes tune down a half step and capo the first fret and that solves the problem. Though, I still don't understand why the nut has to be higher than the frets on down the neck.
(I have a feeling I'm not the first to ask this question)

[Cameleye]

A good setup involving an adjustment to the fret slots can go a long way in addressing this issue.

[RP]

I would think that a guitar with a nut that is fret-high is going to buzz with even moderate playing...

[charles Tauber]

Theoretically, the strings exiting the nut slots do not need to be any higher than the height of the frets. For some players that works fine. For some players, particularly those with a more "aggressive" attack, having the strings exit the nut at the height of the frets will cause the open strings to buzz on the first fret. In that case, a few thousandths of an inch increase in height will eliminate the buzz. A "few thousandths" is literally .003 to .005" above the height of the frets. Much higher than that and it does influence playability and intonation.

[mawmow]

An experienced luthier once told me he saw many peoples bring in
a brand new guitar asking for bigger frets : A higher nut enable such
a job to be done without changing the nut.

I have seen many times high action at nut on brand new guitars.
Martin is apparently known for that : It would leave room to adjust
action to the casual buyer's expectations. The problem is few
sellers actually care when selling guitars : They would give a turn
on the truss rod but never offer to adjust nut and saddle in my
experience.

[AcousticDreams]

While it doesn't have to be much higher than the frets, it still has to be a bit higher.

And the Bass strings, usually are higher than the treble strings.
But a proper adjusted nut will make playing so much easier.

Important to remember, that along with the nut, the right neck relief is also paramount. I was having string buzz on my 4th string. Raising the neck lief just 3 thousands got rid of that buzz.

[KevinH]

Try measuring the string height at the 2nd fret when you have a capo on the first fret. In this case the first fret is now the "nut". Then take the capo off. The string height at the first fret doesn't need to be higher than what you measured. It's common to leave a little extra to avoid buzz. But, in principle, a barre chord at the first fret shouldn't be harder than a barre at the 2nd with a capo on fret 1.

[coyote95667]

I believe if you press a string at the third fret, you need no more than a non-zero space between the string and the first fret. If you can see a gap, it's likely too much. should just be able to hear a plink if you tap it - just enough to prove the string is not laying on the first fret.

I think Martin and some others don't set up the nut perfectly because if you over-shoot, you're screwed and down to superglue and bone dust filler which works but is tedious.

Perfect nut setup just takes too much time so they err on the high side and leave you to it.

[fazool]

Originally Posted by mawmow

An experienced luthier once told me he saw many peoples bring in
a brand new guitar asking for bigger frets : A higher nut enable such
a job to be done without changing the nut......

An "experienced" luthier told you it makes it easier to put new frets in because it has a higher nut?

That's like saying you should keep a rubber band on your shifter because it makes it easier to rebuild the transmission.

And, not to mention if they put new frets on and don't adjust/replace/check the nut then they are a total hack.

[John Arnold]

The only reason for the nut to be higher than the fret plane is to prevent back buzz. That is usually limited to the 6th string (combined with minimal relief), so that is the only string that may require raising a few thousandths.
Logically, placing a capo on the first fret creates a new 'nut' that is fret height. If it does not buzz there, it should not buzz open with a nut that is fret height. Assuming, of course, that the frets are properly leveled.

[Glennwillow]

Originally Posted by Cameleye

A good setup involving an adjustment to the fret slots can go a long way in addressing this issue.

Yes, my own experience is that nut slots are usually cut on the high side and in many cases need to be filed down a little more for optimum playability.

- Glenn

[Dru Edwards]

Years ago I bought a set of nut files from Japan and they do come in handy.

[Scotso]

Originally Posted by Kinda Old

I know there needs to be a nut on a guitar to hold the strings in place. But why does it have to be a bit higher than the frets? It makes chords at the top of the neck harder to play, especially F (barred)
Is there a good physical reason that the nut can't be fret high? I sometimes tune down a half step and capo the first fret and that solves the problem. Though, I still don't understand why the nut has to be higher than the frets on down the neck.
(I have a feeling I'm not the first to ask this question)

A nut properly cut to accommodate most players will allow about 18 to 20 thousands of an inch clearance at the 1st fret of the E string. It can get a bit lower approaching the e string. This allows for the string to vibrate in its arc without buzzing on the first few frets.

[dnf777]

The nut’s role is to hold the strings in place as you mentioned, and to allow the strings to clear the first few frets without buzzing, FOR YOUR STYLE OF PLAYING. The difference is tiny, so adjusting on the high side will only minimally affect playability.

[RalphH]

I've had a nut at exactly the fret height once and the strings rattled against the frets between the nut and where I was fretting on the 3rd fret (took me freakin ages to find. It's called "back buzz" I think)... so yeah, I tiny gap is good. But TINY! They don't vibrate much so they only need a whisper of clearance, but if they are just barely touching the fret tops then you can hear it sometimes. The neck relief is not enough by the 3rd fret to help it clear them.

If you're asking why manufacturers leave them so high, then simple manufacturing tolerances. Better safe than sorry, but yeah, WAY too high, almost always.