Nut angle

Replies to This Discussion

Permalink Reply by Doc Oakroot on May 17, 2009 at 12:42pm

Are you looking at a particular guitar?

You might want the bass strings to have a longer scale length than the treble strings - helps with intonation... at some cost to playability.

But it might just be a visual artistic choice.

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Permalink Reply by Big Steve on May 17, 2009 at 12:51pm

Since I can't play yet the question is only academic. My second CBG goes to my friend who gave me the boxes. Kind of what it to sound better than project 1. Was wondering if mattered.... don't want to go down the road I did with my first CBG, nut to bridge length 29" and frets calculated and marked accordingly but can't get the thing in tune. Probably attributed to light acoustic guitar strings verses what should be bass guitar strings... I don't know. Either way the next box will have a 25.5" nut to bridge length.

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Permalink Reply by Doc Oakroot on May 17, 2009 at 12:56pm

You should probably stick with the nut at 90 deg until you get some experience. But you will need to adjust the bridge for intonation and it will probably not be at exactly 90 deg when you're done. It depends on string material, thichness, and flexibility. If you use similar strings (strings from the same string set), you can usually set the intonation at the top string and then the bottom string, and it will be OK for all strings.

Big Steve said:

Since I can't play yet the question is only academic. My second CBG goes to my friend who gave me the boxes. Kind of what it to sound better than project 1. Was wondering if mattered.... don't want to go down the road I did with my first CBG, nut to bridge length 29" and frets calculated and marked accordingly but can't get the thing in tune. Probably attributed to light acoustic guitar strings verses what should be bass guitar strings... I don't know. Either way the next box will have a 25.5" nut to bridge length.

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Permalink Reply by Big Steve on May 17, 2009 at 1:07pm

I'm not sure what is meant by "intonation"? Is intonation something in addition to tuning? What am I listening for and how do I achieve it?
Sorry for the newbie type question.

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Permalink Reply by Doc Oakroot on May 17, 2009 at 1:34pm

Tuning is getting the open strings in tune - which every player has to do each time he plays.

Intonation is getting the notes on the frets in tune - which is done by the builder. If it needs fixing, most players (of regular guitars) take it to a guitar repair shop to get it done.

Basically, to do it you need to get the 12th fret in tune. If your fret spacing is right, the others will be in tune as soon as the 12th is.

Procedure:

1. Tune the string to the desired pitch.
2. Play the 12th fret harmonic (get a guitar playing friend to show you how). This is always exactly an octave above the string.
3. Fret at the 12th fret and play the note. The target is to get this exactly an octave above the open string.
4. Compare the two pitches.
5. If the fretted note is higher, move the bridge (in very small increments) away from the nut.
6. if the fretted note is lower, move the bridge closer to the nut.
7. Repeat until the pitches match (don't skip step one each time).

Do this for the first string. Then do it again for the last string - moving only that end of the bridge. And you'll have the intonation as right as it can be for those strings and frets.

If you didn't do this for your first build, that may be why you couldn't get it in tune.

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Permalink Reply by Big Steve on May 17, 2009 at 1:51pm

Doc Oakroot said:

Tuning is getting the open strings in tune - which every player has to do each time he plays.

Intonation is getting the notes on the frets in tune - which is done by the builder. If it needs fixing, most players (of regular guitars) take it to a guitar repair shop to get it done.

Basically, to do it you need to get the 12th fret in tune. If your fret spacing is right, the others will be in tune as soon as the 12th is.

Procedure:

1. Tune the string to the desired pitch.
2. Play the 12th fret harmonic (get a guitar playing friend to show you how). This is always exactly an octave above the string.
3. Fret at the 12th fret and play the note. The target is to get this exactly an octave above the open string.
4. Compare the two pitches.
5. If the fretted note is higher, move the bridge (in very small increments) away from the nut.
6. if the fretted note is lower, move the bridge closer to the nut.
7. Repeat until the pitches match (don't skip step one each time).

Do this for the first string. Then do it again for the last string - moving only that end of the bridge. And you'll have the intonation as right as it can be for those strings and frets.

If you didn't do this for your first build, that may be why you couldn't get it in tune.

Ah, Thanks so much for the info. Based upon your simple to understand steps I'll have a go at it.

Big Steve

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Permalink Reply by Don Miller on May 17, 2009 at 3:56pm

If the frets are parallel to each other, the nut should be parallel with the frets. The vertical face of the nut where it meets the fretboard is normally 90-degrees to the plane of the fretboard. The slots in the nut normally slope downwards slightly from the fretboard down toward the tuners, so the front edge of the nut is the highest point. (I say "should" and "normally", but in the Nation there are no rules!)

At the other end, the bridge or bridge saddle is usually not parallel to the frets, in order to adjust for the intonation of each string, as described above.

Occasionally, guitars have a non-parallel nut to adjust tuning problems at the first fret, but it's pretty unusual. Google "compensated nut". Picture: http://www.mimf.com/nutcomp/nut_blues.jpg

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Permalink Reply by Mark Werner on May 17, 2009 at 6:34pm

Normally it's the saddle (the other end) that's "compensated" to account for the intonation problems caused by the different-diameter strings. The easiest way to compensate is the slight angling you often see; a more advanced method (often seen on electrics) is the individually-adjusted saddles.
You also complex "relief" cuts in saddles for the same purpose.

Note that on typical CBGs with their rather short scales, three or four strings that are close in diameter to each other...It's not very critical.

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