Why do guitars go out of tune?

But it's not string wear that makes old strings sound out of tune in higher frets - it's dirt. :)

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Cat, zebra stripes is what Notes was talking about - the frets wearing the string down. But it won't directly cause a string to be out of tune (although it will change the tone of the string)

it's both.

what Cat calls zebra stripes change the mass of the string in wear areas. that means a string's mass/unit length may very well be different for different locations on the f-board due to wear at favored areas of the fretboard and non-linear fret placement (freq of wear). moreover, as the string further stretches at those wear points, the effect becomes worse, even if a relatively slow process (the stretching). ironically, using an electronic tuner may exacerbate the out-of-tuneness higher on the 'board.

from elsewhere:

on "worm gear" slippage: the primary tuner antislip mechanism is purely the geometry of the worm drive -- the near-right angle relationship of the worm and worm gear (it's actually the flat one), not the gasket on the worm's shaft. note that expensive Sloan and Waverly tuners have no such gasket. same is true for vintage and new Klusons that are just fine as far as stability. generally, the gasket/sleeve is only found on sealed tuners with removable buttons. tightening the button screw will affect the button's rotational feel, and can help prevent "bump/vibraton-detuning" but unless the button is almost falling off and the worm in danger of being dislodged (not likely), that adjustment isn't doing anything for directly maintaining a stable string tension.

for those with open tuners. one of the main tuner failure issues with open backed tuners is the loosening of the capstan screw that holds the worm gear (that's the flat gear, not the long 'worm') to the capstan (string post). It's important to make sure that screw is secure, as it can work loose even under string tension. securing with a bit of Locktite is a good idea if you notice a loose capstan screw, as it will come loose again. and you will want to catch the problem before it shoots a few pieces of that tuner to the floor.

many players blame their guitar's tuners for tuning stability issues, but even cheap tuners can work relatively well if undamaged, properly installed, and maintained. usually, the problems are (as noted by many above) poor string wrapping on the capstan (post), catching at the nut, and string wear/dirt. thermal expansions/contractions of the strings, vibrato/trem springs, truss rod and woods are always a consideration as well. I have one "magic" guitar -- G&L S500 -- with floating trem that always stays in tune if I have relatively clean, unworn, 10s on it. even over temperature. it just happens to self-compensate to nearly net zero tuning offsets over a pretty wide range of temp. not for sale.

there were enough wraps, but since it been on there so long, the exposed string had worn down more than the wrapped string, and the wrapped string started stretching after the groove that was in the nut slot or on the tuner slipped. you can tell when it happens because there's a ping sound.
it's like the stretching that happens when you put on a new set of strings.

That ping always means something was binding and slipped. Usually the string in the nut slot. Scares me to hear it when tuning up, as the short segment of string between capstan and nut accumulates extra tension and may break. I lift the string above the nut to release the binding. And look into relieving the binding by opening the slot ("sawing" the string in it often works) and/or applying a bit of lubrication. A properly fitted nut needs no lube.

I certainly understand that playing and wear loosen the strings, makes complete sense. But what I don't understand is why when I tune up, my strings are repeatedly SHARP!?!?!? Not much but slightly. I use the same electronic tuner, I live in a relatively dry climate in No. Cal, it's in a warm room that should be loosening strings, there's no sign that the neck is warping. Is this a sign of nearly imperceptable neck warp? Am I imagining things :roll: or am I living in a mystery spot where water flows uphill? Any clues to what's going on?

Dave "Who" Else

This is probably needless to say, but are you tuning your strings from flat to on pitch? (please forgive me if you already know this).

Also, try putting some pencil graphite in the grooves of the nut when you replace your strings. If the strings are indeed binding in the nut, the tension between the nut and the tuner will be greater than it needs to be, and then when the nut releases the string, it will go out of tune. A small bump or simply a duration of time is enough.

They make 'nut sauce' or something like that for the nut, but when I had my Kramer, the factory tech support rep said pencil lead works just as good and costs so much less.

BTW, my sax, flute, and other acoustic instruments drift in their tuning as well and have to be attended to regularly.

Insights and incites by Notes

Notes,
Yeah, I do flatten my strings before tuning up to pitch. It's just that when I first check to see if they're in tune, I usually find them sharp :?: As far as it binding in the nut, I'm not seeing it slipping out of tune to a lower pitch. I'm probably just losing my mind, but I thought I'd see if anyone else had experienced this or had a better explanation of what's actually happening.

Dave "Who" Else

maybe the strings have probably cooled off, or you're resting the neck in a certain position, or you put pressure on the guitar when you're playing in a way that's not there when it's at rest. those are the most likely reasons.

Ok, OK, I'll come clean.

Guitars go out of tune because I pick them up and start playing them. :oops: :oops: :oops:

consider: if your guitar is binding the string somewhere between the post and the nut (usually at the nut) -- even a little bit, then tuning up from flat up to on-pitch will result in the strings going sharp as that binding releases during subsequent playing. this is because the binding "stores" extra tension between the post and nut, and as it releases, that tension is transferred past the nut to the "live" portion of the string. most of us have experienced this through the obvious "pinging" phenomenon, which is a pathological case of this tension transference. however, sometimes the problem is more insidious, so the binding and release are silent ("pingless")-- except for the annoying tuning ramifications. in the course of doing mods to a guitar, I once replaced a cheap plastic nut with a more expensive self-lubricating nut. the guitar had major tuning stability problems for quite some time, and I thought it might be the cheapo neck, until I figured out that even the slippery nuts are quite capable of silently binding. I did some radical reshaping of the nut to fix this -- removing every bit of "extra" nut material above the plane of the strings and recutting the slots. now it's fine -- and fun to play.

(FWIW, if you happen to tune from sharp down to on-pitch, the opposite would happen; release of the binding will allow the string to go flat.)

Thanks gnease and Notes, now I get it. When Notes said tension between the nut and post, I didn't get the concept that the excess tension could shift to the fretboard portion of the strings. Just restating it made a light come on :idea: that just didn't click the first time I read it.

I'm glad neck warping is (probably) not the cause.

I guess I'll try lubing my nuts (immature snicker) when I change strings.

Thanks,
Dave "Who" Else

Dagnabbit, this morning I posted a post that said much what gnease said above. It's disappeared. Anyway, he's right as usual. :D

I hate it when my nuts bind! :shock:

You gotta worry when they start pinging.

I'm afraid I've got another spin on this topic.
When I had a cheap acoustic, the strings would gradually de-tune over time. To be expected, except that they would become sharp!

Is there an explanation to this? Or was it just that it was a cheap guitar with cheap strings?

If the strings go sharp, it's usually from either a change in temperature or humidity. Temperature changes make things expand/contract, and if the strings contract faster than the wood of the neck (or expand slower) you'll end up with more tension. Humidity changes can make the wood swell or shrink, and if it swells your nut and bridge might be just a bit farther apart, which will also increase the tension.