Contemporary Music Instruction and Mentoring
Adjusting Your Guitar's Truss Rod
On
a steel string guitar (either acoustic or electric), the
tension of the strings tries to bend the neck upward into a
concave shape. The purpose of the truss rod is to offset the
pull of the strings. In other words, the truss rod adjusts
the amount of concave curve in the guitar neck. How much
concave curve the neck has is called “neck relief.” A tiny
bit of neck relief is necessary. The question is, how much?
There are many ways to measure neck relief. However, most people who actually know what they are doing measure neck relief this way: place a capo between the nut and fret 1, then, while fretting fret 14 (meaning holding down a finger between fret 13 and fret 14), measure the distance between string 6 (low E) and fret 6.
Too little neck relief makes the strings buzz, while too much neck relief makes the guitar harder to play. Thus, the ideal amount of neck relief is just enough to avoid string buzz. This “ideal” amount of neck relief varies quite a bit between players, playing styles, string gauge, and the type of alloy the strings are made of. And it especially varies depending on how the guitar has been “set up” (meaning how high the nut is, the neck mount angle, how high the bridge/saddle is, and how consistent the fret heights are.)
No one can tell you how much relief you need. Only you can do that. The way to find your ideal amount is to experiment by reducing relief until you hear buzz when you are playing loudly, then gradually increase relief until the buzzing stops.
You need to obtain the correct tool to adjust your truss rod. Some guitar manufacturers include the tool when you buy the guitar. However, for reasons incomprehensible to mere mortals, some don't. Sadly, this includes Taylor and some other high end guitars. Even more amazingly, many guitar stores throw the tools that do come with guitars away because they don't want to keep track of which tool goes with which guitar. When you ask to buy a tool, some stores don't have the tools in stock, and others don't even know what tool your guitar needs, so they can't even order one. This is a travesty. Every guitar owner needs a truss rod adjustment tool! The bottom line is, unless your guitar came with a tool, you have to find out what tool you need, then either order one or try to find one on Ebay or whatever. For Taylor guitars, the tool is a small, non-ratcheting socket wrench. For all other brands, it is an L-shaped Allen wrench with a longer-than-usual reach. Unfortunately, there are about five different sizes of Allen wrench used by various manufacturers, so it may take some trial and error to find the right one.
The good news is, once you have the tool, adjusting the truss rod is easy!
Find your truss rod adjuster location. On acoustic guitars, almost all brands except Taylor have the adjuster inside the sound hole. Hold the guitar flat, with the neck pointing away from you, and raise it up to eye level, with your eye just above the bridge, looking into the hole, and you will see a bolt with an Allen type head. That is your truss rod. On Taylors acoustic guitars, and also on most electric guitars, look at your headstock, just above the nut, below the strings, and you will see a small cover with 2 or 3 Phillips screws holding it on. Remove those screws and the cover, and you will see a bolt with a small six-sided nut on it. That is your truss rod.
Neck relief is decreased by turning the truss rod adjuster clockwise (tighter). It is increased by turning it counterclockwise (looser). In other words, turn clockwise to lower the strings to make it easier to play, or turn counterclockwise to get rid of buzzing. A little bit goes a long way. It’s a good idea to only go 1/6th of a turn at a time.
Each time you make an adjustment, be sure to retune the guitar before testing for string buzz. This is critical! Also, don’t just check for buzz using open strings. Play various chords and scales.
A good average starting point for neck relief is .010” (0.25mm) — measured with the capo and finger as described above — which is about the thickness of two sheets of regular 20# paper. When you tap the string with your finger above the 6th fret, a .010” gap makes a tiny “tick” sound when the string hits the fret. For more accuracy, you can measure with a feeler gauge (an inexpensive tool you can buy at an automobile parts store). That way, after you find the amount of neck relief that is ideal for you and your guitar, you can get an exact measurement for future reference.
Unfortunately, this is not a one-time adjustment. Many things, including aging of the wood, different string gauges, alternate tunings, and seasonal humidity swings, will affect the neck relief. If you are picky about action and tone, it’s a good idea to check the relief periodically. If not, then adjust your relief a tiny bit higher than ideal, then forget about it unless the strings start buzzing or if the guitar seems harder to play, or if you change to a different type or gauge of strings.
It is important to understand that other things besides truss rod adjustment can cause high action or string buzzing. The truss rod is not the primary way to adjust the action. It is only for fine tuning an already well set up guitar to your personal playing style and for different string tensions. Poor manufacturing quality resulting in uneven frets or incorrect geometry cannot be fixed with a truss rod adjustment. Also, abuse of the guitar (e.g. incorrect humidification) can make the guitar unplayable. If you still have string buzz or hard action after adjusting your truss rod to appx. .005"-.015" relief, your guitar has problems. Nut and saddle height are more critical to ease of playing and lack of string buzz than the truss rod is, but don’t try to adjust them if you are a novice. Take your guitar to a luthier for a setup, THEN adjust your truss rod, and you’ll be smiling from ear to ear.
There are many ways to measure neck relief. However, most people who actually know what they are doing measure neck relief this way: place a capo between the nut and fret 1, then, while fretting fret 14 (meaning holding down a finger between fret 13 and fret 14), measure the distance between string 6 (low E) and fret 6.
Too little neck relief makes the strings buzz, while too much neck relief makes the guitar harder to play. Thus, the ideal amount of neck relief is just enough to avoid string buzz. This “ideal” amount of neck relief varies quite a bit between players, playing styles, string gauge, and the type of alloy the strings are made of. And it especially varies depending on how the guitar has been “set up” (meaning how high the nut is, the neck mount angle, how high the bridge/saddle is, and how consistent the fret heights are.)
No one can tell you how much relief you need. Only you can do that. The way to find your ideal amount is to experiment by reducing relief until you hear buzz when you are playing loudly, then gradually increase relief until the buzzing stops.
You need to obtain the correct tool to adjust your truss rod. Some guitar manufacturers include the tool when you buy the guitar. However, for reasons incomprehensible to mere mortals, some don't. Sadly, this includes Taylor and some other high end guitars. Even more amazingly, many guitar stores throw the tools that do come with guitars away because they don't want to keep track of which tool goes with which guitar. When you ask to buy a tool, some stores don't have the tools in stock, and others don't even know what tool your guitar needs, so they can't even order one. This is a travesty. Every guitar owner needs a truss rod adjustment tool! The bottom line is, unless your guitar came with a tool, you have to find out what tool you need, then either order one or try to find one on Ebay or whatever. For Taylor guitars, the tool is a small, non-ratcheting socket wrench. For all other brands, it is an L-shaped Allen wrench with a longer-than-usual reach. Unfortunately, there are about five different sizes of Allen wrench used by various manufacturers, so it may take some trial and error to find the right one.
The good news is, once you have the tool, adjusting the truss rod is easy!
Find your truss rod adjuster location. On acoustic guitars, almost all brands except Taylor have the adjuster inside the sound hole. Hold the guitar flat, with the neck pointing away from you, and raise it up to eye level, with your eye just above the bridge, looking into the hole, and you will see a bolt with an Allen type head. That is your truss rod. On Taylors acoustic guitars, and also on most electric guitars, look at your headstock, just above the nut, below the strings, and you will see a small cover with 2 or 3 Phillips screws holding it on. Remove those screws and the cover, and you will see a bolt with a small six-sided nut on it. That is your truss rod.
Neck relief is decreased by turning the truss rod adjuster clockwise (tighter). It is increased by turning it counterclockwise (looser). In other words, turn clockwise to lower the strings to make it easier to play, or turn counterclockwise to get rid of buzzing. A little bit goes a long way. It’s a good idea to only go 1/6th of a turn at a time.
Each time you make an adjustment, be sure to retune the guitar before testing for string buzz. This is critical! Also, don’t just check for buzz using open strings. Play various chords and scales.
A good average starting point for neck relief is .010” (0.25mm) — measured with the capo and finger as described above — which is about the thickness of two sheets of regular 20# paper. When you tap the string with your finger above the 6th fret, a .010” gap makes a tiny “tick” sound when the string hits the fret. For more accuracy, you can measure with a feeler gauge (an inexpensive tool you can buy at an automobile parts store). That way, after you find the amount of neck relief that is ideal for you and your guitar, you can get an exact measurement for future reference.
Unfortunately, this is not a one-time adjustment. Many things, including aging of the wood, different string gauges, alternate tunings, and seasonal humidity swings, will affect the neck relief. If you are picky about action and tone, it’s a good idea to check the relief periodically. If not, then adjust your relief a tiny bit higher than ideal, then forget about it unless the strings start buzzing or if the guitar seems harder to play, or if you change to a different type or gauge of strings.
It is important to understand that other things besides truss rod adjustment can cause high action or string buzzing. The truss rod is not the primary way to adjust the action. It is only for fine tuning an already well set up guitar to your personal playing style and for different string tensions. Poor manufacturing quality resulting in uneven frets or incorrect geometry cannot be fixed with a truss rod adjustment. Also, abuse of the guitar (e.g. incorrect humidification) can make the guitar unplayable. If you still have string buzz or hard action after adjusting your truss rod to appx. .005"-.015" relief, your guitar has problems. Nut and saddle height are more critical to ease of playing and lack of string buzz than the truss rod is, but don’t try to adjust them if you are a novice. Take your guitar to a luthier for a setup, THEN adjust your truss rod, and you’ll be smiling from ear to ear.