Getting a guitar in tune, and keeping it in tune, is often an interesting endeavor—in the sense of the ancient Chinese curse: “May you live in interesting times!” Most serious players know that there is a never ending series of adjustments needed to keep your instrument playing right.

Joey Leone’s recent article on the importance of set-up was spot on. Years back, I worked as a salesman in a small, independent music store. I’d never worked in music sales before, so unpacking brand new guitars fresh off the UPS truck was a new experience for me. I quickly discovered that they were almost never properly adjusted. It was a roll of the dice at best. The guitars that happened to come in playing well were the first to go out the door in the hands of happy, paying customers. The other instruments would hang on the wall a lot longer, while we repeatedly explained that a professional set-up would make them play and feel much better. So I got to thinking that if I learned the basics, and at least got the guitars and bass guitars into reasonably good adjustment, sales would go up. I started talking to our guitar tech, and asked him to explain to me how it all worked. He was amazingly patient with me while I relentlessly picked his brains, until finally, I began to “get it.” I got pretty good at setting up the instruments, and sales went up substantially—not that the owner of the store was in a hurry to give me a raise for my efforts!

Still, I was glad for what I’d learned. While major repairs and maintenance (including fret work and the neck set on acoustic guitars) were things I was wise enough not to tackle, routine adjustments became, well, routine. The electrics were the easiest to work with, because most of the adjustments were done mechanically, with a screwdriver and an Allen wrench.

I found a quick way to scope out a truss rod adjustment, without needing the expensive machined straight edge our tech used. Using both hands, I’d just press the bass string down in two places on the fingerboard, simultaneously–say at the third and 11th frets–and then pluck the string with a free finger. If the string bottomed out, it meant the rod was too tight, and the neck too flat. Conversely, if I could see much more than the thickness of a playing card’s worth of space between the string and the frets (looking from the side, as you would while playing), it meant the rod was too loose, and the neck had too much forward bow.

After that, I’d start adjusting the saddles—up or down for string height, and on the electrics, forward or back for string length. These two adjustments—height and length—are highly interactive. If your strings are higher, you have to press them down farther to play a note. That means more stretch, higher tension, and raised pitch—resulting in the need for lengthening the string, by moving the saddle away from the nut a bit. Lower strings mean less stretch, and less need for compensation. Different players like different string heights, of course, so there’s no single right way to do this, but at the store, I’d try to find a middle ground that would satisfy most players.

Nut slot adjustments are something untrained players shouldn’t mess with. The tech showed me how to do them, using an X-acto saw blade and 400 grit sandpaper. If the slots aren’t shaped properly, the strings won’t seat and flex properly, causing all sorts of problems. I started out doing nuts on cheap, entry-level guitars that had action bad enough that I could hardly have made them worse. And amazingly enough, I had a pretty good touch, and was able to do them well. Still, I left the top-of-the line instruments to our tech, though I’ve done the nut slots on my own pro guitars, since then. Ironically, most guitar techs don’t take the slots down far enough, in my opinion. That’s because if they go too far, the strings start buzzing, and they have to make you a new nut, or at least do some extra shimming—things they really don’t want to take the time do. I think the open string clearance between the nut and the first fret should be about the same as the clearance obtained between a closed string (that you’ve pressed down at a given fret) and the next fret up (toward the bridge). That way, you don’t get additional stretch at the first fret, sparing you the all-too-common aggravation of a guitar that plays sharp at the first fret. But talk to your guitar tech about it. As the saying goes, don’t try this at home.

Worn frets make guitars play sharp! That’s because as a fret wears down, the string vibrates from the front edge of the fret, rather than from the crown—effectively shortening the string, and thus slightly raising the pitch. Worn frets can also cause string buzz against higher, less worn frets. If you then raise the action to offset this, you create all sorts of tuning and playability problems. So get your frets worked on, when they need it. A guitar tech I know suggested that changing your strings is like buying gasoline for your car—something routine and inexpensive. Getting your frets adjusted and replaced is like buying tires. More expensive and done less often, but it’s something you simply must do, from time to time.

Keeping your guitar in tune requires strings that still have some elasticity. They don’t have to be brand new, but over time, strings become stiff and brittle, long before they break. Stiff, brittle strings play sharp, so once they reach that point, it’s time for a new set.

String gauges can make a difference, too. I like fairly heavy strings on my Strat. I use a 12 to 52 set, with a wound 3rd string—pretty much the same gauges I use on my acoustic flat top. I find them more stable, tuning wise, than lighter strings, and I like the fatter tone I get. But some people have no trouble with the lighter, faster, 9’s, 10’s, or 11’s. It just depends on your touch and style.

The weather affects your guitar! Humidity swells wood, higher temperatures expand everything, colder temps contract everything, and all of these variations affect the tension on your strings. A guitar can be in tune at home, and get wonky in a cold car trunk on the way to a gig. At the gig, you re-tune the still-cold guitar, only to have it shift on you again as it warms up in your hands, requiring you to re-tune again (and again!). Don’t worry. It’ll eventually settle down. Better still, arrive a little early, and let the guitar warm up before you play it.

Finally, let me just touch on the question of scale tempering. Musical scales are built around theoretical mathematical ideals, but real world instruments have built-in compromises. These compromises are called scale tempering. The modern equal-tempered tuning system was a major innovation developed for keyboard instruments during the time of J. S. Bach, and his composition, The Well Tempered Clavier, demonstrated its effectiveness. Prior to that system’s introduction, you could not play in some keys without retuning your keyboard. These days, most guitars are built according to the equal-tempered system, but ironically, acoustic pianos employ a variation called “stretch tuning,” to compensate for the sharp harmonics generated by their stiff, massive, bass strings. The piano sounds more in tune with itself, but it’s a challenge to get guitars and other instruments in tune with the piano. Guitars with compensated nuts, guitars employing the Buzz Feiton nut and tuning system, and guitars with computer-designed curved frets are all examples of recent attempts to improve tuning accuracy and compatibility with keyboards.

There’s no way this short article can address all of the things that affect how in-tune a guitar plays on its own, and with other instruments. But I hope it points you in the right direction.

Gordon Kaswell is an award-winning composer, working musician (playing guitars, keyboards and bass guitar), and freelance writer. He lives in the Pacific Northwest. You can email him at gordon@efn.org