Setting Up Acoustic Guitars and other Fretted Instruments

A Little Personal History

About that time, my sister Tess brought me home a Mariachi-style twelve-string from Mexico, and that became my main guitar for about ten years. I traded the Kay to a fellow for a Harmony Bass that was just as ugly, but which I used for years, after replacing the guitar tuners with real bass tuners.

When I was working my way through Wright State University's undergrad English program, I was also playing "out" in many coffeehouses. There, and on campus, I met many other struggling college students whose guitars had "issues." I patched holes, reglued (and reinforced) head stocks, rewired electronics, lowered bridges, restrung, tuned, and adjusted, adjusted, adjusted. Later as a part-time guitar teacher, I also adjusted more than one of my students' guitars. And even though I tend to shop carefully, every guitar, banjo, or mandolin I have ever bought (even the professional models) required some sort of adjustment before it truly served my needs.

In other words, everything I know about "setting up" guitars, banjos, and mandolins I learned first by experimenting on low-quality, low-cost "starter" instruments. I am not a luthier or even a guitar tech, really, but I've picked up enough over the years to be able to share what I've learned and hopefully save you or some family member some unnecessary frustration.

Caveats

Most $50 (or so) undersized guitars sold in department stores are not worth the time it would take to make them playable. For some reason, 2011 saw a huge glut of so-called "quarter-sized," "half-sized and "three-quarter-sized" "guitars" on the shelves of WalMart, Toys-R-Us, Target, and other "big box" stores. If someone gives one of your kids one of these instruments, and you want to try to make it playable for him or her, go for it. Most of them are no worse than the Kay I learned on. But don't imagine that you'll turn a $50 guitar into an instrument they'll want to play forever. That said, if you want to practice your "setting up" skills on a guitar you don't mind destroying, and you can get said guitar really cheap at an after-Christmas sale or garage sale, go for it.

Never take on a project you're not quite equipped to do on an instrument you can't afford to replace. Removing, sanding, and replacing the bridge on my $15 Kay was one thing - doing the same on a $1500 Martin is something else.

We are not responsible if you destroy your instrument or hurt yourself - No matter how carefully we write instructions like these, we can't take into account every variable, including shoddy construction, defective materials, prior abuse, or what folks in the computer industry call "user error." Here are a few tips:

• Look away from the instrument whenever you're tightening strings.

• Wear safety goggles or glasses when handling wires or applying pressure or torque to anything.

• Proceed carefully, iteratively with every step listed below, especially steps that involve tools like Allen wrenches or nut drivers. Tweak and test, tweak and test.

• If you have to make major changes, say the neck is really arched and it takes you quite a while to straighten it out, let the instrument "rest" a while before you go on to the next step.

• As you handle the instrument, be on the lookout for things like loose glue or solder joints, stripped or missing screws, etc.

This is one reason we recommend starting out on inexpensive instruments - eventually you get a "feel" for things and you can tell, say, if something is taking a lot more pressure than it "should," or something is taking a lot more time than it should to "settle in."

Can you hurt yourself working on a a musical instrument? In addition to obvious risks like poking yourself in the eye with a guitar string, or puncturing your hand when screwdriver that slips off a screw you're unscrewing, there are less obvious dangers. Like the time a "friend" decided to tune my twelve-string a couple steps too high, and the bridge - under hundreds of pounds of extra stress - exploded away from the face of the guitar and barely missed his face as it arced around.

Setting up a fretted instrument is no more dangerous than the average shop project. But you need to exercise reasonable caution. And don't blame us if you do something stupid and wind up with a b-string in your liver or something.

Tools You Might Need

• A good set of needle-nosed pliers with a built-in wire-cutter - I use this whenever I change strings. A cheap wire-cutter may not do the job, since those are made to cut copper, not steel.

• A set of hex drivers - for adjusting the neck adjustment screw of most guitars (unless the guitar came with one, in which case, don't lose it.)

• A nut driver set (maybe - the neck adjustment screw on some guitars requires a nut driver. Fortunately it's often the same size as the hex shaft on replaceable-bit screwdriver sets.) If you are working on a banjo, you may also need a nut driver to tighten the drum head. Again - if one came with it, don't lose it.

• A soft pillow or other padding to brace underneath the neck while you're working.

• A large pad like two old bathtowels to lay under the body while you're working.

• A tuner crank is especially helpful if you are doing a lot of instruments or setting up a twelve-string.

• A digital tuner or other means of tuning the guitar.

• A small practice amp and a known good guitar chord if you're working on an electric or an electric-acoustic instrument.

• A flat file - In case a fret or two need filed down.

• A triangular file - In case a notch in the nut or bridge needs to be deepened.

• Polish or oil for the fingerboard - Martin's guitar polish will do. If you don't have that but you have Tung oil, Liquid Gold, or even mineral oil for your furniture, that will do in a pinch.

• Polish for the head, neck, and body (or resonator, if it's a banjo) - Again, Martin's guitar polish is very good for this. If you don't have this, a very light Pledge-style furniture polish can be used in a pinch. However, if you use furniture polish on your instrument, you'll need to wipe off the excess very thoroughly - the excess won't evaporate on its own accord like guitar polish.

• A sheet or two of fine or medium-grade sandpaper in case the nut or bridge needs sanded down.

• A very soft, disposable cotton rag for polishing the instrument and wiping off excess polish. Well-used (clean) cloth diapers and old (clean) t-shirts are the best because they are very soft and absorbent.

Have New Strings On-Hand

• Light bronze-wound strings for acoustic guitar or mandolin,

• Light nickel-wound strings for banjo, and

• Extra-light nickel-wound for most electric guitars.

The lighter you go, the easier the strings are to play, but the less tone they have. Experienced Bluegrass musicians with professional instruments often choose medium strings, or even heavy, but that's the exception, not the rule.

Reasons Fretted Instruments May Suck

Beginning players are often put off when an instrument is ugly. And if you're fixing up one of your own instruments, you may decide to improve the look somehow. But, except for covering Hanna Montanna's face with black spray paint, cosmetic upgrades are outside the scope of this article. Most problems that keep fretted instruments from being musical have to do with tone and playability.

Tone may be poor for many reasons, including inferior materials and bracing. But 95% of the time the best way to improve the tone on any instrument is to put new strings on it. So assume the instrument needs new strings, and don't bother starting on it unless you have a plan for replacing the strings.

Playability - On a fretted instrument like guitar, banjo, and mandolin, the worst playability problems usually relate to the strings and fingerboard.

• The fingerboard itself may be bowed so that it is impossible to fret the strings where you need to with out the strings buzzing agains other frets.

• The strings may be so far from the fretboard that it takes fingers (and nerves) of steel to fret simple chords. This may or may not be a result of a bowed or twisted neck.

• The individual frets may be uneven.

Check/Adjust the Neck

If the neck is bowed, locate the adjustment screw access. On most guitars, you can get to the end of the adjustment screw by unscrewing a triangular piece of plastic on the head. On some guitars, you can see the end of the adjustment screw at the bottom of the fretboard, just over the sound hole. If you can't find an adjustment screw period, the instrument may not have one, and the only "remedy" for a bowed neck may be to install lighter strings than you planned, which may reduce pressure on the neck enough for it to pull back a little.

Find a nut driver or hex screwdriver that fits the end of the adjustment screw. They're seldom metric, if that helps, and some instruments even come with them.

Loosen all the strings so they're a few steps flat. Loosen the middle strings enough to get the nut or hex drive into the end of the adjustment screw and make at least a partial turn.

Holding your face well away from the instrument, in case a string snaps, tighten the adjustment screw a bit, then sight down the neck and see if you're having any effect. Keep going until the neck seems fairly straight.

Retune the strings. If you have time, let the instrument sit a bit so the neck can decide whether it's happy where it is - sometimes the string pressure will pull it back into a bow even after you've tightened the adjustment screw.

The last few times I've set up used, but decent guitars, I've gone through this step several times. I leave the old strings on for this step, since all this tuning and detuning is hard on the strings, and I would rather beat up the old ones than prematurely age the new ones.

When you're satisfied that the neck is as straight as you are likely to get it, tune the strings back up and check out the string height (below).

Adjust the Drum Head (If you're Setting Up a Banjo)

If your instrument has a resonator (a round wooden shell that goes on the back of the body), it is usually held on by a few obvious screws. Unscrew those screws, put them in a safe place, and put the resonator aside. In fact, you're probably better off leaving the resonator off until you're done working on the instrument. Now you have access to the nuts that you tighten to adjust the drum head.

You may have got a small nut driver with your instrument. Or you may have to find one in your tool case. Again, many banjo head tuning nuts are the same size as interchangeable screwdriver bits, so you may be able to use a magnetic screwdriver or some such for this.

Loosen the strings again (if you haven't already). Then turn the nut closest to the neck a tiny bit to see if you feel any resistance. If you don't feel any resistance, the head may never have been tightened. If you feel resistance, leave the nut where you left it, then go to the nut exactly opposite, by the tailpiece. Work your way all around the drum head this way. It's common for cheap imported banjos for, say, 2 nuts out of three to actually be tightened - that's enough to keep the instrument from falling apart on the boat, but it's not enough to deliver good sound.

When you're done, tapping the drum head should give a crisp sound, like a snare drum with the snare detached. If it booms, go around again.

You should feel resistance on every nut, but you should never twist any nut more than a quarter of a turn at a time. Whatever you do, avoid tighening up one side of the drum head more than the other side - keep working your way around, the way they showed you when you learned to replace an automobile tire.

You should never have to exert real force to tighten a drum head adjustment nut - if that's the case, you've got the head too tight or some other mechanical problem.

When you're satisfied that the head is tight enough, get the bridge about where you think you will need it and retune the strings.

Adjust Bridge Placement on Instruments with "Floating Bridges"

On the other hand, if you have a banjo, mandolin, or a guitar with a tailpiece, your bridge is probably held down only by string pressure. That means that it can move back and forth, annhilating your intonation if it's got too far from where it needs to be.

In theory, the distance between the nut and the twelfth fret should be the same as the distance between the twelfth fret and the bridge. But measuring exactly will only get you close to where you need to be, because string thickness and other issues affect the optimum placement of the bridge.

To get optimum placement, fret a string just behind the twelfth fret and pluck it. Then hold a finger lightly against the string over the twelfth fret, but without fretting it, and then pluck it. If you're doing it right, you'll get a bell-like tone called an "overtone." If your bridge is placed properly, the overtone will be the same pitch as the note you fretted.

• If the overtone is higher than the note you fretted, the bridge needs to move a bit toward the neck.

• If the overtone is lower than the note you fretted, the bridge needs to move a bit toward the tailpiece.

• The "optimum" placement for the low strings may be different than for the high strings, which explains why the bridges of my banjos are almost always at a slight angle. (You'd be surprised how much that upsets my OCD friends.)

Don't spend too much time trying to get this exactly right now - you'll have to do it over again when you restring the instrument anyway, but it will help the next stage if you can get the instrument to play at least somewhat in tune.

Check/Adjust String Height

When you fret a string at the second fret (by pushing down on it between the first and second fret) the string should just about lay on the first fret, but it should not buzz against the third fret when you pick it. Try this on all six strings. Then do the same test on the third, fourth, and fifth fret.

Check/Adjust Nut Height

The nut may be too high if:

• When you're fretting a string at the second fret, there's more than a millimeter's distance between the same string and the first fret.

• It hurts significantly more to fret a string behind the first fret than it does to fret it behind the second fret.

If only one or two strings seem to be too high, you might be able to fix the problem by filing the little notch(es) a tiny bit deepar and trying again. Remember, go slowly.

On a really cheap guitar, the whole nut may be too high. Generally the nut is barely held on by a dab of glue. So if you loosen the strings enough to lay to either side of the nut, you should be able to pop it out, lightly sand the back, replace it (without glue at first) and try again. The strings should hold it down. Even if you're happy with the placement, don't bother gluing it back in place until you've adjusted the bridge as well (if necessary).

The nut is probably too low if you get fret buzz on the first or second fret when you're not fretting anything on the guitar, especially if you don't get fret buzz further down the neck.

If the entire nut is too low, take off the strings, pop it out, and shim it up with a thin sheet of plastic (a chopped-up credit card may work).

If only one slot on the nut is too low, and you don't want to shim up the whole thing and file the other slots back down, you may be able to fix that one slot with epoxy. Loosen the strings so they don't cross the nut, clean the nut with Fantastic, Formula 409, Glass Plus or some other cleaner that doesn't leave a residue, dry that out, then let it air dry for a spell, then mix some epoxy and dab it into the offending slot, and let it dry thoroughly overnight. Then the next day, use the trianular file to carve the offending slot down to where it needs to be.

Check Bridge Height

Now that you have the nut height where it needs to be and the neck straightened, pay attention to the bridge.

• If the strings are fine at the nut end, but just about laying on the fretboard near the sound hole, the bridge is too low. (If you're working on a banjo, the head may still be too loose.)

• If the strings are fine at the nut end, but over 1/4" away from the fretboard near the sound hole, the bridge is probably too high. Before you start sanding, though, doublecheck the fretboard's consistency.

Checking the Fretboard

The "acid test" is fretting every string at every fret and listening for the string buzzing against the next fret down the fingerboard.

• If there is no buzz at all, your bridge could probably stand to be lowered.

• If the instrument is fairly free from buzz unless you really hit the strings hard, and THAT fret buzz is distributed fairly evenly along the neck, you may have things about as good as you can get them.

• If there is a lot of fret buzz, your bridge probably needs to be raised.

• If fret buzz happens more on the higher frets (the ones closest to the soundhole), check to see if the neck has begun to bow upwards again.

• If fret buzz happens more on the lower frets (the ones closest to the nut), check to see if the neck is pulled back too far and is a bit convex.

Adjusting Fret Height

• If the instrument is fairly free from buzz, but one fret just seems to buzz arbitrarily, sight down the neck and see if that fret seems to be sticking up higher than the other frets. If it is, a couple scrapes with the flat file should take care of that problem.

• Certain frets may be so worn that there is always fret buzz on the next fret down. On a guitar this usually happens on the first string, second fret, second string, third fret, and fourth string, second fret. This indicates that a former owner always played in the same key (in this case, in the key of D). You may need to consider replacing the second and third fret, or you may be able to use your flat file to file down the "offending" places on the next frets down. But proceed cautiously if you go this route, otherwise you may have to file the next fret down and then the next fret, and so forth.

Adjust Bridge Height (if Necessary)

How you adjust the bridge height depends on what kind of bridge you have, and whether it has a pickup built into it or not.

Bridges Without Pickups:

• On flattop guitars without tailpieces, the "bridge" is usually a piece of ivory-colored plastic or bone that fits into a slot on a wooden base that is permanently glued to the top of the guitar. If the bridge is too high, it's usually easy to pop the plastic or bone out, sand the back edge a bit, and pop it back in. If the bridge is too low, you may be able to pop that plastic or bone piece out and shim under it with a sliver of credit card or some such. If that's not possible, your local luthier should have replacement pieces in various sizes.

• Mandolins, arch-top guitars, and a few other instruments may have screw adjustments right on the bridge to raise and lower the bridge. On older, cheap, or abused instruments, the bridge may already be screwed down as far as it can go, though. In this case, you can usually loosen the strings, remove the bridge, lightly sand the bottom edge (preserving the curve, if any), and reinstall the bridge.

• On banjos, the bridge is usually a piece of wood without any adjustment screws. If a banjo bridge needs to be higher, and your drum head is as tight as you feel safe, you may need to buy another bridge. Get measurements first, though, so you're not buying exactly the same thing as you already have. In the meantime, you might try chopping a credit card until you little rectangles you can put under your banjo bridge to raise it. If your banjo bridge is too high, remove it and lightly sand the base. Again, proceed a little at a time here - otherwise you could find yourself ordering another bridge.

• On flattop guitars with tailpieces, the bridge is usually a piece of wood without any adjustment screws, but with a plastic or metal bar going across the top, where the strings cross. Such bridges are usually held on only by string pressure, so if you need to lower the bridge, it's an easy job to take the bridge off, sand a bit off the back and try again. If the part where the strings cross is plastic, you might want to pop that part out and sand the back of that instead. Raising such a bridge is a bit more difficult. You may be able to remove the plastic or metal bar where the strings cross and replace it or stick something under it (like a sliver of credit card) to raise it a tad. Or you may need to visit a luthier and get another plastic bridge piece.

Bridges With Pickups: If your instrument has a molded bridge with the pickup built right into it (like better Ovation guitars), you could check to see if the part where the strings cross the bridge can pull away a bit from the rest of the bridge (once the strings are sufficiently loosened). There may be shims under that part, or room for shims. Removing a shim or two will lower the bridge. Adding a shim (say a sliver of an old credit card) will raise the bridge.

Be Prepared to Compromise - At this point in the setup process, a bridge that is too high will cause little or no fret buz but make the strings hard to push down. A bridge that is to low will cause fret buzz at multiple places along the instrument's fretboard. While you're adjusting the bridge on any instrument that costs less than $1000, you will almost certainly find yourself trying to find the best compromise between ease of play and excess of fret buzz.

Once you feel that you have the optimum nut height, bridge height, and neck tension, it's time to take off the strings.

Oiling and Polishing

You're nearing the home stretch. Once you have the instrument in its optimum mechanical condition, it's time to clean it up, polish it up, and oil the firetboard.

Oiling the Fretboard - Unless you have a heavily-varnished maple fretboard (like some Fender electrics), your fretboard is probably a dense tropical hardwood like rosewood or mahogany. This wood is used for durability and resistance to humidity, but it lasts longer and look better if you occasionally take the time to saturate it with an appropriate oil or polish, then wipe off the excess before restringing the instrument. Martin guitar polish, Tung oil, Liquid Gold, or mineral oil will work, in that order of desirability. Spread it on thick and check on it in about twenty minutes. If it's soaked in some places but not others, spread out the part that is still standing in puddles. If the wood was really dried out, you may need to add a little oil. After another twenty minutes, wipe off the excess thoroughly.

Polishing the Head, Neck, and Body (or Resonator) - With a very soft, absorbent cotton rag and the polish of your choice (Martin guitar polish is the best), polish the instrument's wood parts. Then wipe away the excess. If you use any form of furniture polish, be especially careful to wipe off the excess - it won't evaporate like guitar polish. Then wash your hands with soap. You don't want to be transferring oil to the new strings as you put them on. That includes the natural oil your hands give off.

Restring the Instrument

These days strings tend to be packaged in pairs. If I have a set like that, I put on two strings at a time.

First, make certain the end of the string is properly attached to the bridge or tailpiece. Then run the other end across the bridge, neck, and nut and through the appropriate tuning peg on the head of the instrument. Use your needle-nosed pliers to kink the string at a 90% angle where it comes out of the tuning peg, but don't cut off the string right away. Cranking the tuning knob should cause the string to tighten so much that the string automatically kinks again where it goes into the tuning peg. Keep going unti the string is quite tight. If you have a removable bridge, make certain that the string is crossing the bridge and holding against the face of the instrument. Tune each string as you go, even though you'll need to tune it again as soon as you run the next string. (Each string you add puts more pressure on the neck and takes pressure off the strings you've already run.)

Then run the other strings and tune. Tune again. Now you're ready to cut off the excess strings sticking out of the tuning pegs. With your needlenosed pliers, cut each string off about 1/2" from where it leaves the tuning peg. Dispose of the cut-off pieces very carefully - as they will poke right through trash bags and hurt people who aren't expecting them. Now use the pliers to kink the cut strings downward toward the head, so they don't stick up and scratch or poke you later.

Tune the instrument again. A few minutes later, tune it again. Wash your hands again, wipe the whole instrument down one more time, and play a tune or three. Then tune the instrument again. It should need tuned a few more times tomorrow, a couple times the day after that, and once the day after that. If the instrument continues to need several serious tunings a day, look for bigger problems than the ones you addressed during this setup.

Conclusion