How to Adjust Your Guitar's Truss Rod - the Right Way

How to Adjust Your Guitar's Truss Rod - the Right Way

Successful truss rod adjustment is the key to great guitar action

by Todd Money (Former Repair Manager, Gibson Repair and Restoration-Retired)

A properly adjusted truss rod is key to having great action from your guitar. Although Gibson (and other) guitars are set up at the factory, remember that necks are made of wood, and always under extreme tension. Combined with environmental factors and life on the road, this can cause warpage. Fortunately, a truss rod adjustment may be all you need to get your axe back to top playing condition.

Doing a truss adjustment incorrectly can cause (much) more harm than good—which is why guitarists often have a qualified luthier do the job. However many guitar players have found that if they’re careful and patient, they can do your own truss rod adjustments. And you probably can too...so if you want to give it a try, here’s the scoop on how to adjust your truss rod.

1. Gather your tools. Here’s all you need: truss rod tool or 5/16” nut driver, small Phillips head screwdriver to remove the truss rod cover, and a can of light oil (e.g., 3-In-One, sewing machine oil, or the like).

2. Take off the truss rod cover to expose the adjustment nut.

3. You adjust the truss rod tension by rotating the truss rod with your truss rod tool. Looking down the neck from the headstock, adjustment is the conventional “turning left loosens, turning right tightens.”

4. After removing the truss rod cover, unscrew the truss rod nut. This also loosens the truss rod, which we’ll tighten back up to where it should be in subsequent steps. Hold the instrument in an upright position and apply 2 – 3 drops of oil to the rod’s threads. Continue to hold upright for a few seconds. Periodically oiling the rod will prevent binding.

5. After oiling, replace the truss rod nut, and put some tension on it—not just "finger tight." With the instrument tuned to pitch, fret the low E at the first fret with the index finger of your left hand and at the last fret before the body with the top of your right hand thumb. This method lets you use the string as a straight edge. Note: Some techs prefer to use a capo at the first fret. This frees up one hand to measure “relief” (i.e., how much the neck is bowed slightly to allow a bit of space between the strings and the fretboard) with a small ruler rather than simply "eye-balling."

6. While holding the string in the manner above, use your right hand’s index finger to “bounce” the string at the 7th fret—in other words, check the space between the string and the fretboard. The amount of movement you see is the “relief.” A small amount of relief is necessary to minimize string buzz. If you see no movement because the string rests against the frets, you need to loosen the truss rod to add relief—but see the cautions below before doing anything. Recommendations for preferred relief vary from .010” to 2 or 3/64ths”. Depending on your string gauge, tuning and attack, you’ll need to adjust accordingly. If you’re using a heavier low string and/or tuning down, you’ll want more relief. With standard gauge strings and standard tuning with a lighter right hand attack, less relief is preferred.

7. Repeat the process on the high E string. You may notice more relief on the low E than the high. This is not uncommon or undesirable. There’s more string pull on the low strings, thus the extra relief. The “ellipse”—the oval pattern the string travels when struck—is greater on the bass strings, so the extra relief is welcome. You may need to go back and forth a couple times with adjustments in between to strike the correct balance.

CAUTIONS!

• Always loosen the rod ½ turn or so before tightening.
• Tighten the rod the same way you tune a string: start below the desired tension – loosen, then tighten.
• When more extreme adjustments are required, go slowly. It’s not particularly difficult to snap a truss rod, but it is difficult (read: expensive!) to replace one.
• Do not use a lot of muscle to do adjustments. If turning the rod requires more pressure than say, a stubborn plastic water bottle cap, take the guitar to a qualified tech. If you use the Gibson truss rod adjustment tool supplied with Gibson guitars, use your thumb and fingers to turn it, rather than your entire hand, to reduce the risk of snapping.
• Be patient, and give the neck time to settle in after an adjustment. The neck will often continue to “travel” after adjusting the truss rod—you may tighten the rod and have the perfect setup at 7:00 PM, only to find by morning that the neck is bowed up. Different necks respond differently to adjustment. Above all, go slowly and patiently until the neck’s relief is the best possible for your playing style—enough to minimize string buzz, but not so much to make playing more difficult.

                                                                                                                -HC-

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Todd Money was the Repair Manager at Gibson Repair and Restoration in Nashville, Tennessee, which does repairs on all instrument brands, not just Gibson. He's long been involved with the music industry and is the guitarist with the band Wreckless Behavior and is now enjoying retirement.