nut compensation

Hi everyone. I'm new to the forum, and working on my first ukulele build. I normally build classical guitars, and have a dear friend who is a ukulele player, and decided to build one for them. To get a better feel for the instrument I'm building, I picked up one, and have been teaching myself to play. Great fun. It also helps to have one on hand to take measurements from.

I am more or less using the same guitar build methods, but scaled down to make a tenor thats like a mini version of a classical guitar. On guitars I compensate both the saddle and nut. I have seen a bit on this forum about saddle compensation, but not too much on nut compensation. On a guitar, I usually move the nut towards the bridge by about one mm, and then grind little shelves on the nut to allow different compensation for each string.

I have a vague recollection of reading a ukulele luthier saying he compensates the nut by making the distance from the nut to the first fret the same as the distance from the first fret to the second fret. For a 17 inch scale I calculate this to be about a 1.3mm compensation applied to all strings. Is this a common practice? Can you share your methods?
Thanks
Scott

Is it common practice, no. Do what works for you. Welcome to the forum.

QUOTE=DelSc;1812955]Hi everyone. I'm new to the forum, and working on my first ukulele build. I normally build classical guitars, and have a dear friend who is a ukulele player, and decided to build one for them. To get a better feel for the instrument I'm building, I picked up one, and have been teaching myself to play. Great fun. It also helps to have one on hand to take measurements from.

I am more or less using the same guitar build methods, but scaled down to make a tenor thats like a mini version of a classical guitar. On guitars I compensate both the saddle and nut. I have seen a bit on this forum about saddle compensation, but not too much on nut compensation. On a guitar, I usually move the nut towards the bridge by about one mm, and then grind little shelves on the nut to allow different compensation for each string.

I have a vague recollection of reading a ukulele luthier saying he compensates the nut by making the distance from the nut to the first fret the same as the distance from the first fret to the second fret. For a 17 inch scale I calculate this to be about a 1.3mm compensation applied to all strings. Is this a common practice? Can you share your methods?
Thanks
Scott[/QUOTE]

No its not common practice to compensate the nuts on ukuleles, yet I just corrected the intonation on many of my ukuleles by fitting a matchstick (2mm) up against the nut, correcting the intonation. So, nut compensation works so go right ahead and do what you do.

I'm not a builder, but I will suggest to you that you need to build a ukulele light. VERY light. Something that bugs ukulele aficionados is that guitar builders make ukuleles far to heavy when they simply downsize their guitars. GO light.

Anthony

I'm not a builder, but I will suggest to you that you need to build a ukulele light. VERY light. Something that bugs ukulele aficionados is that guitar builders make ukuleles far to heavy when they simply downsize their guitars. GO light.

Anthony

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In researching for my first build, I ran into this sentiment a lot. A ukulele is not simply a scaled down guitar. You don't need a truss system for one thing, and the bracing and soundboard should be much lighter.

I'd be curious to find out if many uke builders actually plan for nut compensation. It sounds to me like some use it if they need to sharpen intonation and have run out of room to do so at the saddle.

I have played several ukuleles that could benefit from a compensated nut. The short scale length accentuates intonation issues in the first few frets.

So I found the article with the comment on nut compensation. It was in the winter 2015 GAL journal "American Lutherie" and a builder named Michael DaSilva made the comment about making 0 to 1 the same distance as 1 to 2 to compensate. I was wondering if others used this method or had another method they used. I like the matchstick idea, that is ingenious.

Thanks for all the comments on building lighter too. The string tension seems pretty low, so I wasn't going to bother with neck reinforcement, and used solid linings to save weight. I reduced thicknesses and bracing to try and account for the smaller size and lower tension, but it still seems a little stiff to my hands. Im using a cedar top thats .080" thick, which is thinner than what I would use on a nylon string guitar, but the soundboard still feels a little stiff. I may sand the lower bout a little

I do use nut compensation on my steel string harp ukuleles, and it makes a big difference. Nylons don't need it so much, but it is still a small improvement.

Thanks for all the comments. It sounds like its not as much of an issue as with guitars, so I may just shorten the 0 to 1 spacing a little and not worry about intonating individual strings at the nut.

After binding the fretboard I take off the excess binding with a disk sander. This ends up taking a little off the nut end of the board giving some compensation.

When you cut a fret board, the nut is actually already 0.0012" closer- which is half the width of the fret slot (which are usually about 0.0024")- this plus touching up on the disk sander is enough for me on any instrument, not that ive tried the other way which might be better and i just don't know it.

I ended up cutting the fingerboard to allow for nut compensation. I dont think it will hurt, and it might help. Thats a pic of a nylon string guitar that is compensated for individual strings

If you want to go all classical on the build, start by buying the strings you intend to use, since that affects pretty much everything, then you can model intonation on a board with an electronic tuner, or maybe there is a decent enough app these days. Really the only way, everything else is a guess.

In that image, it looks like the luthier adjusted the nut with a rotary tool - is that what it looks like in real life? I'm only curious from a practical standpoint.

I was talking with a luthier the other day and mentioned the discussion about compensation at the nut. He just looked at me in an odd way... thought a moment and said, "It would only effect notes fretted at the first fret. It wouldn't make any difference after that so what's the point?" Doh! I think that might be a good point.

sequoia said:

I was talking with a luthier the other day and mentioned the discussion about compensation at the nut. He just looked at me in an odd way... thought a moment and said, "It would only effect notes fretted at the first fret. It wouldn't make any difference after that so what's the point?" Doh! I think that might be a good point.

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Not quite right... in a way, it only affects the open strings. As soon as you fret a note, the nut is no longer involved.

The usual compensation style compromises between good open and good fretted notes. With nut compensation, you can ignore the open strings and adjust the saddle compensation to optimize just the fretted notes, making them more accurate than usual. Then fiddle the open strings until they sound right as well.

The end result is that you need less saddle compensation than usual. One way to think about it is that with the normal style, you adjust the saddle until the 12th fret note and 12th fret harmonic match. When doing nut compensation, every mm you move the nut end of the string toward the 12th fret, you have to move the saddle end toward the 12th fret as well or that harmonic will go sharp compared to the fretted note.

The nut was cut with a rotary tool. Thats exactly what it looks like in real life (I took the picture with my phone) . For guitars, nut compensation doesn't seem as uncommon as in the ukulele world. As Dennis pointed out, the nut compensation is really to get the open strings to play in tune when all the fretted notes are in tune. It's a compromise because different strings types react to compensation differently.

sequoia said:

I was talking with a luthier the other day and mentioned the discussion about compensation at the nut. He just looked at me in an odd way... thought a moment and said, "It would only effect notes fretted at the first fret. It wouldn't make any difference after that so what's the point?" Doh! I think that might be a good point.

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It affects the tension required for the open string to be in tune. The tension of a fretted note will be the open string tension plus any incremental tension from fretting. So it affects the tuning of all the notes on the string.
Alternately: it puts the open string in tune with the fretted notes