Strat intonation help

Threepwood

Hi,

I'm (finally) in the final stages of my first build - it's been a long time coming! Having strung the guitar with a set of 10s and set string height + bridge intonation, I'm finding that fretted notes across the neck are sharp by ~5-10cent. I've got the harmonics are in tune at the 12th fret, but even with the lightest of touches, fretted notes are sharp.

The action at 1st fret (with capo on 3rd) is ~0.50mm, so not sky-high and having moved saddles around, there doesn't appear to be much left, other than to look at the nut height - I guess? I've attached some pictures of the bridge and nut, hopefully they'll be of some help in diagnosing my woes. The neck was purchased new from Northwest Guitars, so I expected to have to make some changes, just need to work out what those changes need to be...

Also, regarding action, it's a Strat body with a Fender American Std hardtail (string through) bridge - it feels like the saddles are pretty much maxed out, is that normal?

Pics -

Many thanks in advance!

mart

With 10s on, the saddles shouldn't be maxed out. If the fretted notes are sharp, then the saddles need to be further from the neck. If that's not possible, ie the saddles are already as far away as possible, then unfortunately that means the bridge is in the wrong place.

melvynhiscock

The nut needs cutting. The neck sockets on a lot of replacement bodies are a shade too shallow. This seems to be a problem when measurements are converted to metric. A Fender style neck socket should be 5/8in deep and the neck will be 1in. Then it should line up.

ICBM

What melvyn said. The nut is still far too high and the neck isn't deep enough in the body.

With the capo on at the third fret there should *just* be clearance between the strings and the first fret, especially on the plain strings - almost so small you can't see the gap unless you tap the string up and down. About 1/10th to 1/4 of the string diameter is ideal, ie .001" to .002" on the top E, going up to maybe .005" to .01" maximum on the low E. (0.5mm is .02", for comparison.)

After you do the nut and before you deepen the neck pocket I would temporarily shim it the wrong way (shim at the outer end) just to check it will set up properly and there isn't some more major flaw with the fretting or the nut position or something.

JohnB

I agree with ICBM - shim the neck forward - probably less than 1/2 mm and cut the nut lower - check that the strings are leaving contact with the nut at the front face, I had a problem with poorly cut nut slots where the strings wereresting on the back of the nut and that 3-4mm offset is enough to make the frets play sharp.

It may not be easy to deepen the neck pocket at this point - you can leave the shim in place permanently with no problem

Another  problem I have had with premade necks (including Northwest) is that they are too straight and you have to back the truss rod off to get any camber. Northwest have a double action truss rod so this isnt really an issue and shouldnt affect the intonation though.

Threepwood

Many thanks for the responses, it's much appreciated!

I'll be honest, the thought of removing wood from the neck pocket fills me with more than a slight amount trepidation. Having said that, I'm determined to see this project through without sending it in to a tech (despite the fact that they'd make a far better job of it than I could dream of!).

I'll lower the nut grooves and put a shim in to see what difference it makes - I see that shims are usually put in bridge-side of the neck pocket, rather than headstock end, should I be 'shimming' headstock end of the pocket, to correct this?

I should add, having read up on filing nuts, ideally, you end up with half of the string in the groove and the other, exposed to avoid string binding issues. My (uneducated) guess is that I'll need to cut the nut so as the string sits fully in the groove - would this be a bad idea, even if the string wasn't binding?

ICBM

Contrary to what you may often read, the height of the nut above the halfway point of the string makes no difference whatever, because it cannot be in contact with the string.

I prefer to have the full diameter of the string in the groove, if given the choice.

Andyjr1515

Threepwood said:

Many thanks for the responses, it's much appreciated!

I'll be honest, the thought of removing wood from the neck pocket fills me with more than a slight amount trepidation. Having said that, I'm determined to see this project through without sending it in to a tech (despite the fact that they'd make a far better job of it than I could dream of!).

I'll lower the nut grooves and put a shim in to see what difference it makes - I see that shims are usually put in bridge-side of the neck pocket, rather than headstock end, should I be 'shimming' headstock end of the pocket, to correct this?

I should add, having read up on filing nuts, ideally, you end up with half of the string in the groove and the other, exposed to avoid string binding issues. My (uneducated) guess is that I'll need to cut the nut so as the string sits fully in the groove - would this be a bad idea, even if the string wasn't binding?

Ref the shim, yes...it needs to be at the headstock end to raise the action ( which is what you will need to do once you've got the saddles lowered from their extreme angle)

melvynhiscock

With your nut as high as it is, the guitar will not play in tune in the first position as you a stretching the strings to get them to the fret. Either get a decent tech to do it, or dive in yourself, it shows how in both of my guitar making books, Remember you do not need fancy nut slot files either if you are careful. I do smile when people use a 10thou file for a top string. Firstly if the slot is 10thou for a 10 thou string it will bind and creak, and secondly  please try and tell that you can cut, by hand, to a tolerance of 1 thou! I could do with a laugh. In the mean old days before people made useable tools we had to make do with what was available. A narrow needle file could make a V groove that would support the string well enough. for the fiddly strings there were small saws. It may not be 'acceptable' in the eyes of the 'luthiery police' to do that these days but it can still be done and I doubt most casual players would even notice the difference if it was done right. If you cut too deep then you can pad up the nut slot with glue and dust from filing down the top of the nut. Some people use superglue and bicarb. I have never used that so cannot comment.

ICBM

Andyjr1515 said:

Threepwood said:

I see that shims are usually put in bridge-side of the neck pocket, rather than headstock end, should I be 'shimming' headstock end of the pocket, to correct this?

Ref the shim, yes...it needs to be at the headstock end to raise the action ( which is what you will need to do once you've got the saddles lowered from their extreme angle)

I don't really like to permanently shim the neck that way, but it will work to assess whether the guitar *can* be set up and intonated properly before you go to the trouble of deepening the neck pocket… it would be very annoying if you went to all that trouble and it wasn't!

I don't like shimming the neck that way because to me it always makes the guitar feel odd, but some people don't mind it. As said earlier the thickness of shim you need is actually quite small, the height change at the neck pocket is much smaller than the result at the bridge saddles.

JohnB

You could also try stringing with a 9 - 42 set, you will still need to deepen the nut slots to reduce the bend when fretting on the low frets, but thinner strings do need less compensation than thicker and Strats normally come ex factory with 9 - 42 (or is that only with a trem?)