Most guitarists know that the playability and overall feel of a guitar is affected by the guitar’s scale length and neck width. The “third dimension” influencing playability is string action, the height at which a guitar’s open strings float above the frets.
Determining the Right Action Height for You
Below, I describe some standard string action guidelines used by many guitar makers and technicians. Very few accomplished players, however, have their guitars set up with “factory default” string action. Almost all of them have their strings a little higher or a little lower than average. Understanding some of the factors that influence the pros’ preferences can help you zero in on the right string action for your playing style.
On the most basic level, displacing a string by a greater distance (be it horizontal or vertically) requires more sustained force, so higher action will be inherently more challenging for beginning players who have not built up much finger strength. String action has a number of more subtle effects on both playability and sound, however.
|High||• More dramatic classical vibrato|
• Clearer articulation of the plucking of individual strings, especially with fingernails or pads of fingers
• Clearer ringing of individual notes of a “raked” chord
• Clearer articulation of each note in a run, slur, or trill
|Blues-style” vibrato (rapid micro-bending of string) is difficult to generate and can sound “pixelated.”|
• Harder to create a unified sound when strumming a chord
• Notes have a staccato, clicky sound when a pick is used.
• Harder to play rapid runs or rapid sequences of block chords.
|Low||• Easier to generate “all at once” ringing of a chord strummed with thumb or pick|
• Easier to play rapid runs, slurs, or trills
• More dramatic “blues-style” vibrato (rapid micro-bending of string)
• More “blended” sound of a raked chord or rapidly played arpeggio
|• Chords can sound “muddy,” without clear articulation of individual notes|
• Notes played during rapid runs, slurs, or trills can “bleed” into each other
• Harder to generate effective classical-style vibrato
• Harder to articulate the individual pitches of a raked chord
It should be immediately clear from the table that higher action is more conducive to classical playing, while lower action (within reason) has advantages for folk, blues, and some jazzy playing. It is therefore not surprising that nylon string acoustic guitars are customarily set up with higher action than steel string guitars.
As with all aspects of guitar setup, however, what ultimately matters is what feels right and enables players to get the sound they want. Intermediate-level players should experiment with different action heights to learn what works best for them.
The “right action” for slide playing is a debate unto itself.
Most of the issues addressed in the above table would be of little interest to a steel-string player using a slide (“bottleneck”). The primary concern of slide players is avoiding contact between the slide and the fretboard or the frets themselves, since such contact generates a lot of undesirable noise and clicking. Therefore, most slide players set their action quite high, as will be immediately evident if you ever try out a National or Dobro steel guitar at your local guitar shop.
There are exceptions to every rule, however. Early blues guitarists who played in both slide and fretted styles did not have the luxury of traveling with two instruments or of constantly raising and lowering their string action. They were forced to develop a feather-light touch with the slide, and the effect is quite pleasing to the ear. Listen, for example, to Robert Johnson’s “Phonograph Blues” or “Come On in My Kitchen.” To this day, there are acoustic blues specialists who protest that raising the string action of one’s guitar to facilitate slide use is “cheating.”
The Importance of “Relief”
Whether a guitar’s action is low or high, it is critical that the guitar is properly set up so that there is relief. To understand relief, imagine holding a straightedge along the length of the fretboard. If the neck were perfectly flat, the straightedge would make contact with every fret. The effect of such a setup is disastrous: any string set vibrating harshly rattles against multiple frets. Therefore, unlike the neck of a violin or cello, the neck of a guitar must be slightly bowed when the strings are tightened to pitch.
The gap between the frets and the straightedge created by that slight bowing is the relief. Typically, the relief on any acoustic guitar, measured at the 8th fret, is about 0.05” (1/20”), less than a millimeter and a half. Yet it makes all the difference in the world. Adjusting the bow of the neck, and hence the relief, can be done by tightening or loosening a guitar’s adjustable truss rod. If you have a vintage instrument without a truss rod, neck adjustments should be left to the most skilled of luthiers.
How String Action Is Measured and Adjusted
String action is measured at the first and 12th frets by measuring the distance between the top of the fret and the bottom of the string. The action will and should be slightly higher on the sixth (bass E) string than on the first (treble E) string. It will be higher because the heavier bass strings naturally bow the neck more than the thin treble strings. It should be higher because bass strings vibrate “bigger” and so need more clearance from the frets.
Adjusting string action requires raising the guitar’s saddle by inserting shims, or lowering it by planing, filing and/or sanding it. A number of videos on the subject demonstrate how this can be done, if your guitar’s saddle is easy to remove. The key relationship to remember is that since the 12th fret marks the halfway point of the string, the amount that the saddle is raised or lowered should be twice as much as the desired change in the action.
Where to get new or spare saddles?
From my experience, it might be convenient to buy several blank saddles and experiment with them. Make one with very low action, one with medium and one with high action. Saddles are usually quite easy to install and remove, so you might try all of them and decide what works for your the best without being scared of breaking the last saddle.
These days, there are plenty of options for buying guitar saddles. It begins with no-name blank saddles from eBay and Amazon, then goes to luthier-focused companies such as StewMac and LMII, and ending by specialized companies as listed below. Bone saddles are preferred, but there are other materials (such as tuck) that work well too.
Bob Colosi is a well-known person in guitar world. He makes and sells saddles, shims, bridge pins and other parts for guitarists who like to tweak their guitars themselves. I used shims from Bob for raising action on one of my guitars. They came very well packaged, with superglue and detailed instruction explaining how to sand the shims to the size of the bridge slot and the saddle.
For my Takamine TC132SC classical guitar, I bought once a couple of compensated tusq saddles from the GraphTech company and was fully satisfied with the results. The company is focused on using new materials in guitar parts, and it worked for me quite well. They also make compensated saddles for Taylor, Martin and other popular steel string guitars, so you might pick one and use it with minimal tweaking & sanding.
The Stats: Common String Action Standards Used by Luthiers
Many guitar setup reference guides will suggest a standard action for steel string acoustic guitars of 3/32” (0.09375”) on the bass side of the neck and 1/16” (0.0625”) on the treble side, measured at the 12th fret. The customary guideline for classical guitars is 1/16” higher—that is, 5/32” (0.15625”) on the bass side, 1/8” (0.125”) on the treble side. Naturally, many players of nylon string crossover guitars choose an action in between these two standards.
Remember, however, that few top-level guitarists are playing instruments set to standard action. Individual luthiers also develop their own idiosyncratic deviations from the guidebooks. Remember also that when considering differences as small 1/64”, the very thickness of a mark on the measuring device becomes an issue.
StewMac.com, a reference site for guitar makers and technicians, suggests these action measurements:
Steel String Guitars
Bass E (sixth): 0.090” at 12th fret (slightly below 3/32”); 0.023” at first fret
Treble E (first): 0.070” at 12th fret (slightly above 1/16”); 0.013” at first fret
Bass E (sixth): 0.156” at 12th fret (very slightly below 5/32”); 0.030” at first fret
Treble E (first): 0.125” at 12th fret (exactly 1/8”); 0.024” at first fret
String Action on my Guitars
Action on my steel string Taylor 416CE-LTD (2011) is approximately two times lower than the one from StewMac. The main reason is that I play mostly fingerstyle, and it’s more convenient for me to play when the action is quite low.
Bass E (sixth): 0.09″ at 12th fret; 0.014″ at first fret
Treble E (first): 0.06″ at 12th fret; 0.014″ at first fret
My nylon string classical Takamine TC132SC guitar, as expected, has much higher string action than above. Even with that, it’s considered relatively low for classical guitar, mainly because I don’t play pure classical music and non-plugged acoustic concerts where it’s necessary to project clear loud sound without any kind of amplification.
Bass E (sixth): 0.12″ at 12th fret; 0.02″ at first fret
Treble E (first): 0.12″ at 12th fret; 0.02″ at first fret
String Action Comparison Table
|Scenario / Guitar||String||Action at 12th Fret||Action at 1st Fret|
|Typical steel string guitar||Bass E (sixth)||0.090"||0.023"|
|Treble E (first)||0.070"||0.013"|
|My Taylor 416CE-LTD||Bass E (sixth)||0.090"||0.014"|
|Treble E (first)||0.060"||0.014"|
|Typical nylon string guitar||Bass E (sixth)||0.156"||0.030"|
|Treble E (first)||0.125"||0.013"|
|My classical Takamine TC132SC||Bass E (sixth)||0.120"||0.020"|
|Treble E (first)||0.120"||0.020"|
String Action Measurement Tools
There are many different tools on the market for measuring string action. One such tool is a combo gauge created specially for guitar. I bought the original one from StewMac several years ago and fully satisfied with it, but these days there are other options that are cheaper and provide a bit more features such as double-sided gauge with measurements both in inches and millimeters, or a tool allowing to measure fret wearing level.
These string action gauges work well, but I found that my eyes are not so good anymore for finding tiny lines under the strings anymore. Also, they are difficult to use for measuring action on the treble E (first) string on the 1st fret – a nut blocks the gauge from moving to the right (closer to the headstock – see the picture above) when the action is higher than usual.
To mitigate these two issues, I decided to try a feeler gauge used primarily in the automotive industry for measuring the gaps in the spark plugs. I bought one from a local Harbor Freight Tools store, it worked just fine and I liked it even better. The only recommendation I have is to pick the one with the thickness numbers well etched and contrast.
Here are a few examples from Amazon, that include a couple of string action measurement gauges, a feeler gauge, and a combo kit including both of them.