Intonation and Neck Adjustments

Why do some guitars seem to just play themselves while others make you work at it? In many cases it's simply a  matter of "setup" -- getting the neck, the string height and the string length just right for your individual playing style. Here's a step-by-step procedure for easy, do-it-yourself guitar setup:

    Tools needed:
    1.  Nut driver, 1/4" or 5/16". You'll probably need one specially made for guitar
         truss rods. Purchasing info on truss rod wrenches at the end of this article.
    2.  Metal ruler or straight edge, 20-25" long
    3.  Small ruler with 1/16" increments

Steps
       1.
Put on new strings. String action (height), fret buzz and intonation will vary
         with different string gauges and from old to new strings. You want to do your
         setup under actual playing conditions, so string your guitar with the gauge of
         strings that you're going to play. If you're replacing strings on a new Gibson,
         most solidbody electrics (Les Pauls, ES-335s, Nighthawks, Flying V's, SG's)
         come from the factory with light gauge strings, beginning with .009. The Chet
         Atkins SSTs and hollowbody electrics (ES-175) come with .010s. Most flat
         tops are strung at the factory with medium gauge, beginning with .013.

       2.Tune up to standard pitch . Again, your guitar needs to be in playing condition,
          so tune up to standard pitch (or whatever tuning you'll be using).

       3.Check the straightness of the neck. Use a straight edge to determine if a truss
         rod adjustment is needed. If the neck is bowed, there will be a space under the
         middle of the straight edge where the neck does not touch the straight edge. If
         the neck is "backbowed," the frets will touch in the middle of the straight edge.
         (Bows are 'sags' in a fretboard... Backbows are 'humps' in a fretboard.)

       NOTE: A slightly bowed neck is ideal for most playing styles. A perfectly
         straight neck generally requires higher string action than a slightly bowed neck in
         order to minimize string buzz at the higher frets. Repairmen describe this as
         giving the neck some "relief" to allow for string vibration. The amount of relief
         necessary varies with playing styles, however. A perfectly straight neck may be
         fine for a very light picking style. If your neck has only a slight bow, you may
         not want to make any adjustments to the truss rod.

         I like to start with a perfectly straight neck. If I can't get the neck straight, then
         that indicates other possible problems, such as high frets (frets being pushed out
         of their slots), low or worn frets, or variations in the fretboard itself, Many older
         guitars have a "bump" in the fingerboard over the neck block, for example. All
         of these problems are fixable, but require an advanced level of repair
         experience. An elevated fret can often be corrected by a gentle tap seating it.

       4.Adjust the truss rod (if necessary). First loosen the G and D string so as to
          access the truss rod cover. Then remove the truss rod cover. If the neck has
          too much of a bow, then the truss rod should be tightened with a clockwise
          turn of the nut. For a clockwise turn, the arm of the nut driver should
         start on the treble side of the fingerboard and move toward the bass side. Don't
         turn the nut more than a quarter of a turn at a time and do not apply excess force
         if it "refuses" to turn lest you twist off the rod. For a backbowed neck, the
         truss rod should be loosened with a counterclockwise turn of the nut. When the
         neck is as straight as you can get it, then back off about a quarter of a turn for
         "relief" and to allow for the tension the G and D strings will apply when tuned.

       5.Check string height. Tune to standard pitch. With the small ruler on top of the
          fret, measure the distance to the bottom of the string. (You can also use a feeler 
         guage for these measurements.)

         The string height at the 1st fret will determine if the nut slots have been cut to the
         
proper depth. If the nut slots need to be deepened or filled in, that's a job for a
         pro with the proper tools.

         The string height at the 12th fret will determine whether the saddle should be
        
raised or lowered.

         Gibson electric specifications are:
              1st fret- treble side - 1/64"
              1st fret- bass side - 2/64"
              12th fret- treble side - 3/64"
              12th fret - bass side - 5/64"

         Gibson acoustic specifications are:
              1st fret- treble side- 1/64"
              1st fret- bass side- 2/64"
              12th fret - treble side- 5/64"
              12th fret- bass side- 7/64"

       6.Adjust saddle height. On an electric guitar with a tune-o-matic bridge, or on
         an archtop guitar with a height-adjustable bridge, the thumbwheels will raise or
         lower the bridge. You may have to loosen the strings a bit to get the bridge to
         raise easily. On an acoustic, the bottom edge of the saddle will have to be
         shaved or sanded off to lower the action, or shimmed or replaced to raise the
         action. You'll have to loosen the strings to remove the saddle, then file it down
         on a flat file -- just a little at a time -- and then replace the saddle and tune up
         again. Don't try to file the top of the saddle, since it's rounded to match the
         radius of the fingerboard. And make sure the bottom remains flat or the bridge
         will want to rock in its slot and not make good contact with the top of the guitar.

         If you are unable to bring the strings to a comfortable height for playing, you
         may need a neck set. Another option is to remove the bridge and either shave it
         down or replace it with a higher one. The optimum height for a wood bridge on
         a flat top guitar (just the bridge, not including the saddle) is 3/8", so if you're
         going to have to go much above or below that, the neck set is the better
         solution. Either way, it's a job for a pro.

       7.To lower the nut slots, special nut files are required that are available from guitar
         shop supply sources. Stewart-McDonald carries them. Set nut slot depths
         to specs listed above for first fret.

       8.Check for fret buzz. Using a medium pick or light finger touch, check all fretted
         notes for string buzz. If correct, move up the next step. If not, some fret leveling
         may be required. This is another procedure for a pro with the right tools.

       9.Check intonation. At the 12th fret, play a "chime tone" by touching the string
         without pressing it to the fret. Release your finger from the string as you pluck it.
         You should hear the octave overtone. Now press the string to the 12th fret and
         play. If the tones match, then the intonation is correct. Notice that the 12th fret
         tone may vary according to how hard you press the string down. Electronic tuners
         are excellent tools to determine if intonation is correct at open string and then
         the12th fret..

      10.Adjust intonation. On an electric guitar with a tune-o-matic bridge, the length
         of each individual string is adjustable. If the 12th fret tone is higher than the
         string's natural octave overtone, then lengthen the string by moving the saddle
         toward the tailpiece of the guitar. If the 12th fret tone is lower than the octave
         overtone, then move the saddle toward the neck.
 
        On an electric guitar with a wraparound tailpiece, the tailpiece can be adjusted
           only at the treble end and bass end. It is usually not possible to achieve perfect
           intonation for every string with a wraparound tailpiece. If an individual string is
           out of tune, you may be able to compensate by replacing that string with a
           higher or lower gauge string.

       On an acoustic archtop guitar, you can only adjust string length by moving the
         entire bridge. Loosen the strings so that bridge will move freely without
         scratching the top of the guitar.

         On an acoustic guitar, the bridge can't be moved but it can be "intonated" so
         that the point where a string crosses the bridge is either forward or after the
         center of the saddle. In some cases, a thicker saddle is necessary to accomplish
         this. Intonating the saddle should be done by a professional and it can correct
         only minor intonation problems. Major intonation problems on acoustic guitars
         -- especially older models -- may be the result of an improperly placed saddle.
         In these cases, perfect intonation can only be achieved by re-routing the saddle
         slot or installing a new bridge and saddle.

      11.Advice. If you want to attempt some of the more advanced setup and repair
         procedures, such as fret leveling, neck set or saddle replacement, first arm
         yourself with the proper instructions and proper tools, then try your hand on a
         junker guitar before you attack your favorite instrument.

    For further reference: Parts, tools and repair books: Visit Stewart McDonald's
    website at www.stewmac.com to order a catalog and browse through repair columns
    by Dan Erlewine.

    Books and videos on guitar setup and repair:
         Stewart McDonald, www.stewmac.com
         Elderly Instruments, www.elderly.com
         JK Lutherie: www.jklutherie.com

    Truss rod nut driver/wrench: Many Gibsons came with a wrench-type nut drive, with
    a small arm mounted at a 90-degree angle from the truss rod. The wrench-type are
    fine for the occassional user.  The pros use a nut driver with a 6-inch shaft that ends
    in a T-bar. You can order either style from Stewart McDonald at 800 848 2273:
         Wrench type 1/4" (for Gibson electrics and some acoustics), part #944, $4.98
         Wrench type 5/16" (for recent Gibson acoustics), part #946, $4.98
         T-bar nut driver, 1/4-inch, part #941, $13.45

1. Packing and Shipping Tips
2. How to Adjust Necks and set Intonation for proper playing action.
3. How to Set UP electric Guitars.
4. Taking Care of Guitar Finish
5. Fretboard care and Treatment (Fret Polishing, etc.)
6. Return to Main Page of The Old Closet!