If your guitar could use a tune-up, there are several things you can do at home to get it playing, sounding, and looking its best. Here we give primers on acoustic guitar maintenance, including adjusting the truss rod (neck relief), saddle height (action), fixing loose tuners, and properly (and thoroughly) cleaning the instrument.
How to Adjust an Acoustic Guitar Truss Rod
A change in string gauges, climate (especially a change in humidity), or simply the player’s taste may require a truss rod adjustment, even on a new guitar. An adjustable truss rod is a slim steel rod embedded in the neck. One end is threaded for an adjusting nut and is accessible at either the peghead or through the soundhole. The other end is anchored to give the adjusting end something to tighten against.
Tightening or loosening the adjustment nut adds or lessens pressure on the rod and neck. As a general rule, tightening the nut moves the neck away from the string pull and removes upbow; loosening the nut allows the neck to relax into an upbow again (especially when helped by the strings’ pull).
Your truss rod needs adjustment when the neck of your guitar has too much or too little upbow or too much backbow. Two primary signs tell you that your truss rod needs adjusting:
- There’s a noticeable change in the action; the height of the strings over the frets has become either too high or too low. The most common scenario is that the strings get higher as the neck upbows from the string pull.
- Some strings buzz on the frets between the nut and the fifth fret. This indicates that the neck is either too straight or it is backbowed from the truss rod’s slow, constant pressure over time.
How to Check and Adjust Saddle Height
Your guitar’s bridge saddle is the most significant piece of the puzzle when it comes to raising or lowering action. Most modern guitars have a drop-in saddle that can be removed when the strings are off. Here are the steps to do it yourself. [Note: If you have a vintage-style through-cut saddle, changing the height is best left to a pro.]
- First, take some action measurements at the 12th fret on the two outermost strings while your guitar is strung up to pitch, from the top of the fret to the bottom of the string in 1/64-inch increments. (The average string action of the guitars I set up is 3/32 inches on the bass side and 1/16 inches on the treble side.)
- To change your action height at the 12th fret a certain distance, you must multiply that number by two to find the height to raise it at the saddle.
- To slightly raise your saddle in a pinch, any hard, flat material will do. Hardwood veneer strips work great, but cutting up an old credit card into strips as wide as your saddle slot works nicely as well.
- To lower your saddle, mark the saddle under the low and high strings and connect them with a straight line. Then, on a bench vise or ample flat surface, file or sand (with 80-grit sandpaper) away the extra material from the bottom of the saddle until you hit your line, checking periodically to make sure the bottom is still square to the sides.
- To make sure the bottom of the saddle is truly flat, you can run it back and forth over some 120-grit sandpaper on a flat surface. This step is especially important for maintaining string balance if you have an undersaddle pickup.
- Consider that your saddle must fit deep and snug in the slot without wiggle room, that the saddle top radius should match that of your fingerboard, and that the desired saddle height should probably not average less than 1/32 inch or more than 3/16 inches above the bridge
How To Fix Loose Tuners
Inspecting your tuning machines is not only an important part of regular maintenance, but it may just solve that mystery buzz or rattle you’ve been wondering about.
- Check the bushings and washers with a nut driver (usually 10 mm) or small adjustable wrench to make sure they are snug but not too tight. (If you have vintage-style press-in bushings, make sure they are seated all the way down against the peghead.)
- The button screws should be snug but not so tight that the gears are hard to turn
- If one of your wood buttons just spins without raising the pitch of the string, the metal insert in the button may have stripped. To fix this, remove the button from the gear. Use a drop of thin superglue to affix the outside of the insert to the inside of the button hole, but try not to get any glue down inside the insert
- For open vintage-style or classical gears, a drop of three-in-one or Tri-Flow oil where the worm and gear meet will help keep them running smoothly
How to Properly Clean Your Guitar
After playing, wipe your instrument clean (using a damp, soft cloth) of any body oils, sweat, or other nasty stuff it may have come in contact with. A soft cloth is the best thing to use to polish and clean guitars (don’t use paper towels). An old 100 percent cotton T-shirt makes a great guitar wiping tool too, and the more it has been laundered the freer it will be from lint.
Fingerprints, smudges, and other dirt may respond well to a trace of moisture. “Huff” some warm breath on the surface the way you would if you were about to wipe the inside of your car’s windshield. If you need a bit more cleaning power, try moistening the wiping cloth with a little mild detergent in water.
Follow the damp wiping by buffing with a dry cloth to remove any streaks.
Here are some notes on commercial guitar polishes and cleaners.
- Water-based cleaners (which look semitransparent in the bottle) should be sprayed on the cloth rather than the instrument and will clean up water-soluble dirt best.
- The creamy polishes may have a slight abrasive and are best avoided if you have a matte-finished guitar (too much polishing can cause a semigloss finish to become shiny in patches).
- Oils will remove oily smudges but may not have any effect on water-soluble dirt.