Types of Guitar Components Explained
Here we explain what components are used to make a guitar. We explain the difference in quality and what components are used on budget, mid range and high end guitars.
What is a machine head?
Anyone familiar with a guitar will know what a machine head is but they may not know the technical term. They are often referred to as the guitar tuners, tuning pegs, tensioners, tighteners or gear heads. Simply put they are the component on a guitar used to adjust the string tension whilst also preventing the string from slipping. Once tensioned it’s important that the string is held in place without slipping to maintain accurate tuning.
There are a variety of machine heads to suit different budgets and they are an important component to consider when building quality guitars. They affect tuning accuracy and contribute to the stability of the guitars tuning. They contain several moving parts and some designs are more susceptible to wear and tear than others.
Sealed or Diecast machine heads are used mainly on quality mid to high end guitars. The internal mechanisms are sealed inside a diecast housing meaning the components are protected from the elements and will permanently retain its lubrication. The diecast housing keeps the gear mechanisms firmly in place making a more accurate string tensioner and holding the guitars tuning more stable. Diecast machine heads are long lasting, accurate, quality guitar components.
Open machine heads or also referred to as vintage were the original machine head design used on steel string instruments. They are an evolution of the side mounted machine head design used on classical guitars. They are built from several components including a chassis, bushing, cog and threaded peg. The back is either open with the cogs exposed or housed with a covered back. This type of machine head is mainly used on budget guitars or high end guitars that require a vintage look. This sounds strange but the type of metal used in their construction has a big effect on their accuracy, longevity and quality. Hence they can be very cost effective or expensive to make.
The internal mechanisms are exposed to the elements which makes them susceptible to damage over time. The components are at a greater risk of wearing out or becoming more difficult to use and less accurate as they gather dust and debris.
Side Mounted (Classical Guitar)
Side mounted machine heads are used on classical nylon string guitars. They are mounted on the side of the headstock, usually in gangs of 3. The cog and threaded peg design is ideal for the lower tension required on nylon stringed instruments making them less susceptible to string slippage. A good indication of their practicality is that the design has changed very little since its introduction in the 19th century.
What is a fret?
Frets are the metal strips that run at regular intervals along the fretboard (finger board). The number of frets on a guitar neck vary depending on the type of guitar, typically a steel string acoustic guitar has 20 frets and electric guitars range from 22 to 24.
Fret wire or frets are an important component that will affect the guitars playability. The type of metal they are made from will have the biggest impact over all. The three main metals used for fret wire are brass (a gold colour), nickel and stainless steel (both a silver colour).
Brass is not as hard wearing as nickel and stainless steel. This makes it a good choice for nylon string guitars but not so good for steel string acoustic guitars. Nickel is a better choice for quality steel string guitars because it is considered corrosion resistant and hard wearing. Stainless steel is a less common choice as it tends to have a more rigid structure which makes it harder to work with but is most resistant to corrosion.
Fretboards and Bridges
The type of wood used for a fretboard and bridge is important to consider when building quality guitars. It has an impact on the way the guitar plays and sounds. Hardwoods such as Rosewood, Ebony and Purple Heart are the best choice for acoustic guitars. Maple, Rosewood and Purple Heart are popular choices for electric guitars. They all have fantastic tonal qualities, are hard wearing and transfer sound waves efficiently to the rest of the guitar.
Ebonised fretboards and bridges are a more cost effective way to produce these components but some of the tonal properties are lost. Ebonisation is a process of darkening or dying softer light woods to look like Rosewood, Ebony or Purple Heart. Ebonised wood fretboards and bridges are not as hard wearing and only produce a portion of the tonal properties of a hardwood.
What is a truss rod and do all guitars have them?
Wooden guitar necks are prone to bending from changes in temperature, humidity and atmospheric pressure. There is also a lot of tension on a guitar neck from the guitar strings. Therefore quality guitars have a truss rod inserted under the fretboard that runs the length of the guitar neck. A truss rod is essentially a metal rod that can be tightened or loosened to control the bend in a guitar neck. Not all guitars have them but it’s an important component to consider when building quality guitars.
At Stretton Payne we use dual action truss rods which is a modern design that can be tightened in both directions, warping the neck in either direction. The truss rod is accessed on an acoustic guitar using an allen/hex key inside the sound hole. Generally on an electric guitar the truss rod is accessed at the headstock, sometimes hidden under a decorative plate.
A truss rod allows small adjustments to the neck position, also know as the guitars action. The truss rod can be used to adjust the guitars action, making the strings either closer or further away from the fretboard. It’s generally considered that a higher action (strings further away from the fretboard) is good for strumming styles of play and a lower action (strings closer to the fretboard) is good for lead guitar. Guitar action is a personal choice but having a quality guitar with a good dual action truss rod will help set the guitar neck perfectly.