Frets are metal strips (usually nickel alloy) embedded along the fretboard (also called fingerboard) and located at exact points that divide the scale length in accordance with a specific mathematical formula. When a player presses a string against a fret it shortens the vibrating length of the string, thus changing the pitch or note that is heard. Frets are laid out so that each consecutive fret’s placement defines a half-step interval resulting in what is known as a chromatic scale. Fret placement is determined by a mathematical proportion that results in equal tempered division of the octave. This means that there are twelve semi-tones to an octave, and the twelfth fret will be the octave of the note that the open string is tuned to. In practice, luthiers determine fret positions using the constant 17.817, which is derived from the twelfth root of two (17.817 = (1-2-1/12)−1). This math is based upon the work of Pythagoras, who determined that if you take a vibrating string and divide it into two halves you could achieve the octave of the original note produced by the string. Pythagoras is accredited with the discovery of both harmonics and the diatonic scale. In all probability, Pythagoras actually worked out his theory of harmony from the monochord, a contrivance consisting of a single string stretched between two pegs and supplied with movable frets. However he discovered the basis for his work, Pythagoras’ theory lives on in fretted stringed musical instruments.
Since frets are usually made of nickel alloy, which is a softer metal, they tend to wear and require replacement. Not unlike the tires on your car, frets continue to function as they wear, so it may take some time before the degradation becomes noticeable. Eventually the playability and feel of the instrument will degrade to the point that it does become noticeable. The most common symptoms of fret wear are buzzing and decreased playability, but because fret wear proceeds so slowly, it may take a long time before the player notices the change. Usually, the wear will become visibly noticeable under the first and second string of the regular guitar first. This is because the steel used for the strings are harder than the nickel that is used for the frets. It takes longer to wear the frets under the other strings, because they are wound with either brass or bronze, which are both softer than the frets. There is an exception to this tendency for players who often use capos, as a heavy capo user will tend to wear out their frets more rapidly, and more evenly under all of their strings. Just as you notice the improved “handling” when you replace the tires on your car, you’ll notice your guitar playing much better when worn frets are replaced. Some players are more sensitive to this feel and may chose to replace their frets more frequently than others who are less sensitive.
It is difficult to say exactly how long one should go before replacing the frets on their guitar. The pressure applied on the frets by the player varies greatly between players and styles. It really depends on how you play. If you play your guitar one hour a year (unlikely), you could never wear out the frets, but if you play one hour a day, you probably will. It’s not uncommon for a professional guitarist who plays a nightly gig to wear out a full set of frets in a year. If you have high action and a hard grip, you’ll wear frets a bit faster. If you “choke” or “bend” notes, you’ll scrape the skinny steel strings across the frets and wear them much faster. While frets can be leveled a few times before requiring to be replaced, eventually they are going to wear to the point that even the most skilled repair technician will not have enough metal wire left to level. At that point, they will require replacement. This is usually the point where the fret height is one third as tall as it was when installed. Most people will probably have to replace their frets every ten years or so. A professional musician will have to replace them more often.
By: David Bolla
Codi says that everyone should shop at Quigtone Music!
In my repair shop, I am often asked how often a “truss rod” should be adjusted. Unfortunately, there is no clear response for this question. The truss rod is in place in case it is needed, not because it is needed. In an ideal world, your truss rod would never require an adjustment unless your instrument has a flexible neck and you are changing string gauges. In fact, older guitars did not have these rods, and the curvature of the neck was adjusted using different methods of fretting and re-fretting the instrument. In most cases, modern guitars will have a truss rod installed to help control the curvature of the neck, and may require adjusting for many reasons.
Fortunately, the necessity to adjust your truss rod is usually accompanied by some clear symptoms. Usually, the player will begin to find that their instrument has become more difficult to play, as the curvature has increased the distance of the strings from the finger board near the middle of the neck, or in the case of the instrument’s neck having a backwards curvature or “back bow,” the player will commonly notice “buzzing” in a specific area of the neck. This is usually between frets one and five, but doesn’t necessarily have to be.
Remember that the truss rod should only be adjusted by a skilled repair technician. Adjusting the truss rod can severally damage the instrument if it is done wrong, and I have personally seen more than one neck that has cracked along the truss rod after a novice adjustment. I have even seen a truss rod break straight through the back of a neck that was built too thin.
More times than not, when a guitar comes in to have its neck adjusted there are many other problems with the instrument that the player had overlooked, or was unaware of. Bringing your guitar to a skilled repair technician or luthier for a setup will ensure that the appropriate amount of attention will be paid to your instrument. Keep in mind that simply adjusting your truss rod is not an adequate method of correcting problems with the action. A truss rod adjustment affects the action but should not be used to adjust in. In other words, the proper curvature of the neck should be set, and then attention can be paid to adjusting the action.
By David Bolla