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I regularly see two camps on setting nut action. One camp says the nut action needs to be higher than the frets while one camp says nut action should be at or near fret height.

My logic puts me squarely in the camp that say nut action should be the same as fret height (a hair above fret height is OK, .002" to .004", but not mandatory). I've never seen any logical reason that I understood for having the nut action higher. I find many factory guitars nut action at .020" to .040" higher than the frets.

I hear these reasons for having a higher than frets nut action:
1.To avoid string buzzing: This does not make sense to me. The nut is just the zero fret. All the frets are at the same height (hopefully - I have never seen a staggered fret height (unpractical) design!) and the guitar can be set up to eliminate string buzzing easily for the frets and nut.

2. To allow for wear: This makes some sense to me. But as the nut is wearing, so are the frets. And in practice a player can usually go a long time with the nut a fret height before it wears down, yielding nice ease of play the entire time which a higher nut action does not allow. (As an aside, the first fret on many players' guitars often wears lower than the second fret and yet the playing of the first fret note does not buzz on the 2nd fret. This says that the nut could be even slightly lower than than fret height and still work. Of course I don't recommend this, but it shows that setups with higher than fret height nut action is not necessary.)

3. Because players tend to play open strings harder/louder: This makes no sense to me. Musical dynamics are to serve the music. There could be true musical service by playing 6 notes louder than the other 114 notes IMHO.

4. The luthier/technician saves money: This I understand. It is much safer and easier to set the nut action higher than the frets and avoid the mistake of accidentally going too low. But this goes against doing what is best for doing what is expedient.
I am not looking for contention or arguments here. I am honestly looking for logical technical reason(s) for why nut action should be higher than the frets. I must be missing something for so many people to be in the camp that sets nut action significantly higher than the frets.

Ed

Well, I don't know anything, but I have heard this.

The nut wears because the tuning of strings saws through it. The frets are not subjected to that.

In classicals, there is some kind of compensation afforded by the raised nut that makes for closer to "in tune" notes, which my ear cannot discern.

The longer the string, the wider the vibration. So, the open string does have a slightly higher chance of buzzing. In the best action on classicals, each of the lower frets is raised a little compared to the fret in front. This is accomplished by building relief into the neck (i.e. bowed in a precise manner). This lets you have a lower action, but without excessive buzzing.

Well Ed my friend I will throw out yet a third possibility here and that is that nut slots need to be cut to work great for the player, take into account the strings used and as such may be above the fret height, equal to the fret height AND in some circumstances below the fret height....

How can this be??? How could a nut slot be cut below the fret height?

When a nut slot is properly cut using the method of fretting between the second and third fret while checking the string's height over the first fret we want to cut the slot so that the string does not make contact with the first fret but is as close as possible.... So close in fact that if done well you may not be able to even see it clearing the fret but you may see the presence and absence of light in the gap and possibly hear the "tink" sound when the string is pressed into the fret.

So when we understand this we also understand that a string may be very close to the first fret so close in fact that as the string clears the nut at the angle of set-back of the head stock that some gauges of strings when they hit the edge of the leading edge of the nut and extend into free space arch a bit before assuming the plane of the speaking length of the string. Because of the very slight arch as the string leaves the nut it's possible for the nut slot to be cut lower than the height of the first fret.

I'll add that a guitar that is set-up to have room for future wear on the nut slots is IMHO a guitar that will be more difficult to play than it needs to be for how ever long it takes to wear in. As such it may not get played.

What Hesh said!
Every string instrument has to be set up for the guage of strings ,and the players needs.

Mike

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Mike Collins

Does a player need to have graduated fret heights so that fret 20 is the lowest height and each one in succession gets higher in height with the nut being the highest yet? A player could tell you he needs this, right? You could, with difficultly, build it this unpractical way, but would you? Or would you try to talk to the player with some logical insight as to why he does not really need this? My point is, players' desires and needs are two different things. I see no logical technical reason for why a player needs to have the nut higher than the frets, and I have not heard a technical reason as to why. Just because he wants it is not a sound TECHNICAL reason. I am looking for logical TECHINICAL reasons. A player wanting it is a business reason, but not a technical reason. If he needs a nut higher than the first fret, then it follows logically that he must need a higher 1st fret than the 2nd fret. And a higher 2nd fret than the 3rd fret and so on.

All,
Help me with some technical reason (not a business reason like "the player wants it") for why the nut should ever be higher than the frets. If you have a reason then please explain why the frets should not also be graduated in height.

Again, I am trying to lean why, not argue for the sake of arguing.

Ed

Building relief into the fingerboard is the way that complex fret heights are usually handled. The frets then are all the same height off the fingerboard, but the whole system is curved. In classicals, it is my understanding that the top builders build the nut groove heights various amounts above the first fret for each string. Also, they build relief into the fingerboard. They do not tell the clients, and the clients are oblivious to this, usually. So, it is not for the client's desire, but for long proven experience that the action and intonation is better. I have seen some mathematical descriptions of the reasons that I do not understand, and I am an engineer. These subtle variations in the fingerboard and string height were develped by luthiers generations ago, by people who did not have training in math and physics. They just realized the benefits. So, how can this be proved to you?

Certainly neck relief creates some some "complex fret heights" handling as you say, but this is very gradual. Having the nut significantly higher than the first fret, as is often done, is not a gradual change like that achieved by neck relief. Of course, the nut participates in the curve of the neck relief anyway, just like the first fret and second fret, so why would it need extra height? There is no difference in height between the first and second fret, so why is extra height needed specially for the nut? I see no logical relationship between neck relief and extra nut height over the rest of the . A guitar with a zero fret has the height of the zero fret the same as the remaining frets.

My thread is not questioning neck relief. I still see no logical technical reason for the nut to be higher off the fretboard than the first fret. The fact that the nut participates in the neck relief just like the first frets is all the more reason to eliminate a need for extra height.

As for you saying that "long proven experience that the action and intonation is better for classical guitars", there must be a logical technical reason. This is what I am looking, the reason. Just to say it is so is not enough to make me a believer. If the action gets better by raising the nut, why not raise it more. Logically, action gets easier when the nut is lowered in my experience, not raised. A classical could be built with a zero nut couldn't it?

Ed

One reason string height at the nut may need to be higher than fret height is to prevent back buzz.

Also my experience is that, if you try to cut your string slots to fret height, you get buzzing at the first fret. The only reason I can guess as to why that is....

Possibly the string vibrates differently near the nut due to the fact that the slot prevents sideways vibration. The energy that would normally cause a string to move in all directions may get converted in a way that causes more relative up/down movement near the nut than at other spots. But that's just speculation trying to figure out an experiential phenomenon.

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http://www.chassonguitars.com

Thanks Todd. A technical discussion/reason as you have approached this question is what I was looking for. Sincere thanks for your thoughtfulness.

I believe that I have followed what you said, but I still do not see a clear technical reason for having the nut any higher at all than the frets' height to prevent buzzing. If the nut needs to be designed higher than the frets to prevent buzzing it would lead to the logical conclusion that designing the first fret to be higher than the second fret would also have a design benefit. And if this is true, it leads to designing the 2nd fret higher than the 3rd fret and so on, at least for some distance up the neck.

Guitars play fine without buzzing on fret 20, 19, 18, ... 5, 4, 3, 2, 1 and bang, magically it will not play without buzzing unless the nut is higher than the frets. This makes no sense to me. The nut participates in neck relief just like the other frets. The nut participates in the action created by saddle height just like all the other frets. The nut is much like another fret and guitars designed with zero frets work without buzzing. I still see no technical reason for the nut to be any higher than the frets to prevent buzzing. And if there is a good technical reason, then it will apply to the frets too. There must be a benefit for having a 1st fret higher than the 2nd fret.

For sake of discussion, lets say that as the neck (scale length) of a guitar gets longer and longer that more and more saddle height is needed to avoid buzzing at the lower frets (1st fret) as they get farther and farther from the saddle. Is this true? (I think it is.) So maybe the problem is that as the saddle is lowered in setting up some guitars, the "bank becomes broken" so that the first fret is the lowest fret (farthest from the saddle) that will play without buzzing. That means playing the zero fret (nut) open now buzzes. This leaves two options to correct: 1) put money back in the bank by raising the saddle or 2) raise the zero fret (nut) to be slightly higher than the first fret. I believe that this is what has happened traditionally with the guitar. Rather than raise the saddle, the nut has been raised higher than the frets out of traditional set up. The benefit of raising the nut is no greater than the benefit of raising the saddle IMHO (actually, not as great IMHO). In fact, with a higher saddle we get a little more down force on the top. In fact, with a lower nut we get a tiny bit more down force on the top (likely insignificant, but greater force is going in a better direction than lower saddle and higher nut for downward top force).

This leads to an interesting observation. As the scale length gets shorter (short scale) the nut gets closer to the saddle and closer to where the first fret of a longer scale guitar would be. Tradition says that the first fret of the long scale guitar can work fine without buzzing, and yet when you move the nut to that location on a shorter scale guitar it will case to work fine and start buzzing. In other words, tradition says that short scale guitars need nuts that are higher than the frets too, just like long scale guitars need higher nuts. This makes no sense to me.

I am still honestly open to accepting different logical technical reasons for having the nut action higher than the frets. Please keep the explanation coming. I know it is difficult when tradition is questioned.

Ed

Back buzz.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Howard,

Please explain in detail:
- What are all the factors that prevent back buzz?
- Is peghead angle involved?
- Are machine head heights involved?
- Is there is no design to prevent back buzz except having the nut higher than the frets?
- In Todd's example how does a nut that is only .008" or .002" higher prevent back buzz?
- How can a zero fret guitar be made to work without back buzz?

Please help with these questions with some technical details about what you mean and how it works.

Thanks in advance.
Ed

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Thanks for the logical technical explanation, Howard. It makes sense to me.

So a nut which is only a tiny bit above fret height (.002" to .008" in Todd's example) solves back buzz which still allows us to be very near fret height. So there seems to be no call for .020" to .030" as is often seen.

Thanks,
Ed

My experience is the same as Kent's. That's all the logic I need.

The other reason is as Kent also stated and Howard further explained - back buzz.

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Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

For sure, lots and lots of guitars have nut slots way too high.

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Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

Howard,

I understand what you mean by back buzz, but I have not had the problem with which to deal. As I have thought about it, it seems that every time I put a capo on the first fret I am effectively moving the the nut down to fret height, and I have been fortunate enough to have avoided back buzz to date while playing on higher frets. I assume that this is because most guitars that I play have .005" or thereabouts of neck relief.

Is it very safe to say that with some neck relief the need for extra nut height over the fret height is not typically needed? In other words, it may be needed to solve a back buzz problem but usually is not needed due to having some neck relief?

Thanks,
Ed

Hi Ed,
I generally find that 0.015 for the treble strings and about 0.025" for the bass strings (at the 1st fret) is the ideal setup for my customers. Sure you can get away with the fret height at the nut and not get buzz - or else when you capo at the 1st fret you would have a buzzing problem. However, most of my customers are fingerstyle players that play in alternate tunings quite a bit. This style often involves plucking an open string with a fair amount of force and letting it sustain while other notes are played.

Here's the real point. You want the action as high as possible while still maintaining really easy action. This gives the player more ability to strike the strings with greater force if they so desire. I have found that with an action of 0.07" for e and 0.09" for E at the 12th fret plus the numbers I posted at the beginning give incredibly easy action but still allow my players to play with a lot of force in alternate tunings and not get any buzz on the open strings. By giving yourself a little extra room at the nut you can avoid open string buzz in alternate tunings. This also allows you to keep the action as dictated by the saddle relatively low. You could raise the saddle more but then I find playability suffers. And it is really those open strings that seem to plucked the hardest by players. I recently sent two guitars off before Christmas with this particular setup. Both of these players were largely classical players and couldn't believe how great the action was.

In other words, it isn't necessary to do this for all players but for many players (especially the alternate tuning fingerstyle crowd) they will really enjoy that particular setup. It all comes down to what suits the player. You won't be doing the same setup for everybody.

Thanks for the thoughtful post, Simon. I appreciate you sharing the measurements and thoughts behind your setups. Very helpful.

My opening of this thread detailed my thoughts about players that play open strings harder than fretted strings. To do this regularly does not serve the music. I find it sad that many players do this, but I am one to try and face reality. Question, these many players that play the 6 open notes louder than the other 114 notes, what do they do when when they capo now that the nut that you have raised to allow them to play their open nutted notes louder is out of play and no longer in use. Do they just keep playing the open capoed notes louder and live with the buzzing? This is a sincere question.

Ed