why wont my guitar stay intonated ?

[parabola]

title says it all

my guitar usaully wont stay intonated for more than 30 minutes now .
ive never had that problem before. why is it doing it now ?
i just put on new strings (heavier gauge than normal, but it still intonates...just doesnt stay intonated). I also, just got a graph tech nut. An I use the string locking method when i string my guitar. My guitar neck has a slight concave in the neck. oh yea, its an epi lp just so you know. Is there something im missing ?

[ShredMAN]

Re: why wont my guitar stay intonated ?

Intonate one more time, but this time measure and write down the possitions of the saddles, next time when it seems its intonated incorrectly, check to see if the measurements are the same

[Norman_T]

Re: why wont my guitar stay intonated ?

Have you properly stretched your strings - have you tuned up each string a tone and then brought it back to normal pitch and then done this again a couple more times? You may also find that because you are using slightly heavier strings that your nut may also need to be re-cut.

Don't even attempt to try intonating the guitar until such time as the guitar has properly "rested" with all the stretching of the strings - this may take a day or two or even better play it out tune and do some bends and anything that you normally do. Then intonate again and you may well fine that it will be alright and should stay in tune and be properly intonated.

[Mike M.]

Re: why wont my guitar stay intonated ?

You said you put a heavier gage than normal on your guitar. If you go from say, .009's to .010's that will throw your intonation off and you'll have to adjust your bridge saddels to get the open strings and 12th fret harmonics the same.

[parabola]

Re: why wont my guitar stay intonated ?

thanks for the replies.
i'll intonate one more time today ande file some slots of the nut down to help the string sit in there better.

[Wattage]

Re: why wont my guitar stay intonated ?

What are you suing to ensure proper intonation?

[parabola]

Re: why wont my guitar stay intonated ?

ran into another problem
when i play my g string on the twelth fret it's slightly sharper than the harmonic on the 12th fret and my saddle is as far back as it can go. Also, almost all fretted notes before the 12th fret are sharp on other strings when the intonation is correct on the 12th fret. Would filing or raising the nut help ?

[Norman_T]

Re: why wont my guitar stay intonated ?

Before you start doing any filing of the nut - have you got a floating trem? if you do I have feeling that this may be causing some of the problems. The vintage and US Standard (two-post) trems are designed to float with their front edge down and their rear edge up, with approximately 3/32" gap between the bridge and the body at the rear edge. You will need to lock your trem in place while you perform other adjustments.

First, loosen the two screws that hold the claw in the rear of the guitar, loosening its screws will allow the bridge's rear edge to rise. You don't need to loosen them to the point where the screws fall out, but loosen them several turns so the rear edge of the bridge is higher than it should be. Now, in the rear of the guitar, look for the gap between the trem block (the metal block that the springs plug into) and the rear wall of the trem cavity (the wall closest to the butt of the guitar), and push a small wedge into it. This wedge is something you can make out of wood; it should be about 1/2" wide, 1.5" long, and roughly 1/8" to 3/8" in thickness. As you push the wedge into the gap, you'll see that it forces the rear edge of the trem back down towards the top of the guitar. Push it in until the bridge is positioned in its proper floating position.

Be sure to push the wedge in at the center of the block, that way you'll be able to use the screwdriver a little later to adjust the two claw screws without moving the wedge. Now, with the wedge in place, you'll see that you can tune the guitar to pitch without the bridge pulling up and set your bridge height/saddles and intonation. Be careful doing the rest of the adjustments that you don't dislodge the wedge as it will be sticking out of the back of the guitar. Take care when you hold the guitar, and especially if you lay it down on a bench or table.

Hopefully that should be the problem sorted out for you

[Sabe]

Re: why wont my guitar stay intonated ?

I once had a similar problem with an SG. Wouldn't stay intonated at all, or in tune for more than 2-3 songs.

Turned out there was a micro-fracture in the neck, right under the headstock. It took a few months until it became visible, and that's when I noticed it, and the tuning became even more difficult to hold as well. Started out as a hairline, but eventually grew to a "lightning bolt", and finally became large enough where you could stick a fingernail into it.

I had the crack professionally fixed, and now it stays in tune (and fully intonated) with no problems at all.

I think if you have an angled angled headstock too, that there's a chance you have a crack in there that you might not see yet. Hold it up to strong light, and use a magnifying glass to inspect the grains.

If you think you've got a hairline crack in there, relieve the string tension asap until you can get it to a shop. good luck.

-sabe

[Norman_T]

Re: why wont my guitar stay intonated ?

Before you start doing any filing of the nut - have you got a floating trem? if you do I have feeling that this may be causing some of the problems. The vintage and US Standard (two-post) trems are designed to float with their front edge down and their rear edge up, with approximately 3/32" gap between the bridge and the body at the rear edge. You will need to lock your trem in place while you perform other adjustments.

First, loosen the two screws that hold the claw in the rear of the guitar, loosening its screws will allow the bridge's rear edge to rise. You don't need to loosen them to the point where the screws fall out, but loosen them several turns so the rear edge of the bridge is higher than it should be. Now, in the rear of the guitar, look for the gap between the trem block (the metal block that the springs plug into) and the rear wall of the trem cavity (the wall closest to the butt of the guitar), and push a small wedge into it. This wedge is something you can make out of wood; it should be about 1/2" wide, 1.5" long, and roughly 1/8" to 3/8" in thickness. As you push the wedge into the gap, you'll see that it forces the rear edge of the trem back down towards the top of the guitar. Push it in until the bridge is positioned in its proper floating position.

Be sure to push the wedge in at the center of the block, that way you'll be able to use the screwdriver a little later to adjust the two claw screws without moving the wedge. Now, with the wedge in place, you'll see that you can tune the guitar to pitch without the bridge pulling up and set your bridge height/saddles and intonation. Be careful doing the rest of the adjustments that you don't dislodge the wedge as it will be sticking out of the back of the guitar. Take care when you hold the guitar, and especially if you lay it down on a bench or table.

Hopefully that should be the problem sorted out for you

I am a total idiot just realised that the above refers to strat guitars and you have an LP guitar Sorry about that and Sabe could well be right in that there could be a hairline fracture (I do hope he's wrong) but perhaps someone else could chip in with any suggestions?

[texasguitarslinger]

Re: why wont my guitar stay intonated ?

ran into another problem
when i play my g string on the twelth fret it's slightly sharper than the harmonic on the 12th fret and my saddle is as far back as it can go. Also, almost all fretted notes before the 12th fret are sharp on other strings when the intonation is correct on the 12th fret. Would filing or raising the nut help ?

I had the same issue with my Epi LP on the G string. I just took off the wire guard that holds the saddle screws in place and reversed the direction of the 1st (High E), 2nd (B) and 3rd (G) saddles. I put the wire guard back on and voila! This made it more than easy enough to get that G string to intonate.

[parabola]

Re: why wont my guitar stay intonated ?

I had the same issue with my Epi LP on the G string. I just took off the wire guard that holds the saddle screws in place and reversed the direction of the 1st (High E), 2nd (B) and 3rd (G) saddles. I put the wire guard back on and voila! This made it more than easy enough to get that G string to intonate.

hey thanks for the advice ... i tried that and it worked.
now i just have to get the intoantion set on the 1st - 12th fret.

how far should the string be in the nut ? Right now my low e, a and d string are almost all the way in, but the notes are still sharp. Is it ok to go any lower ?

[parabola]

Re: why wont my guitar stay intonated ?

The string should only seat into the nut about 1/2 to 3/4 it's thickness.The distance from the bottom of the string to the top of the first fret should be about 1/16" to 3/32".

really ? My g, b and high e are in about 1 1/2 its thickness . I didnt even file those slots . As for my lower strings .... how would i get the first 12 frets to intonate properly if i shouldnt file the nut slot anymore ?

[parabola]

Re: why wont my guitar stay intonated ?

bump

[MattPete]

Re: why wont my guitar stay intonated ?

really ? My g, b and high e are in about 1 1/2 its thickness . I didnt even file those slots . As for my lower strings .... how would i get the first 12 frets to intonate properly if i shouldnt file the nut slot anymore ?

Unfortunately, if your string is correctly intonated at the 12th fret, then the lowered number frets will be slightly sharp, especially near the nut. That's just the way it is with standard guitars.

Lowering your nut height can help. The reason that those notes are sharp when your guitar is intonated at the 12th is because of the increased break angle over the nut for those frets. This is especially true for the 1st fret, where the extra break angle required to fret stretches the string, increasing it's tension, and making the note go sharp. By lowering the nut, you decrease this angle.

The only way to get around this is to modify your guitar to use a shelf nut (ala Buzz Feiten). You could make one yourself by ordering an Earvana nut, filing away the compensation so that it is flat, and then have it overhang your fretboard by a mm or 2.

One thing that might help: when intonating any guitar, use your normal fingering pressure. You might find that when you play, you press harder than you do when you intonate Therefore, if you intonate with your normal pressure, the 12th would be slightly flat if played with your weak intonation pressure (I hope makes sense). By intonating this way, it should help the lower numbered frets to be less sharp.