The tuning problem -- explained.

The real culprit is the friction of the strings in the grooves of the nut. When a tuning peg is tightened the part of the string that is above the nut receives greater tension than the rest until the imbalance is enough to overcome the friction -- and the pitch of the string goes up. The same thing happens when the peg is loosened. The imbalance remains -- just below the threshold of force needed to overcome the friction -- if not corrected. When played in this state the vibration of the string will reduce the friction, and the tension will equalize. The result is that the string will go out of tune. This may seem obvious to some, but not everyone. What to do about it?

First, as mentioned in my "Restringing Neatly" page, lubrication definitely helps. I use a cheap disposable mechanical pencil to 'color-in' the groove. Graphite is definitely the best choice because it is dry. I apply it every time I change my strings -- but it doesn't entirely solve the problem.

The solution is to equalize the tension when the correct pitch has been attained. This simply means backing the peg off a little bit. The trick is to back it off just the right amount. A tuning peg has a range of motion between pitch up and pitch down caused by the aforementioned friction. It is the center of this range that the peg needs to be backed off to. It is easier said than done because the range will be different for each string. The longer the string is between the nut and peg the more it will stretch, but also the thinner it is the more it will stretch. On a guitar with a standard head configuration, the low E string will need very little if any correction and the G will need the most. To find the range, slowly tighten until the pitch rises then loosen until the pitch falls. Now tune the string up (or down) to pitch then back off half the determined range.