The acoustic guitar tuning machines are not all the same. Even this small detail of the headstock has a crucial importance on the guitar sound: it serves to adjust and keep the strings in tension.
In this article, we will analyze technical and aesthetic aspects, but a basic premise is fundamental: you can not choose low-quality tuning machines. Just think how often you will tune your guitar or you will adjust the strings to get an idea of how important the tuning machines are.
Not all guitars equip tuning machines of good quality, it is necessary to well evaluate this detail during the purchase if you do not want to return soon to the store.
Or you can choose to buy a good guitar and then to replace the tuning machines: it will certainly be easier to replace them than the neck or other components of the instrument.
If you need help to buy your new instrument, you can read our tips on how to choose an acoustic guitar.
Acoustic guitar tuning machines features
The main feature to which you must pay attention is the tuning machines position on the headstock of your instrument: while in the classical guitar there are three placed on each side of the headstock, in the acoustics, it is possible to find them on both sides or on a single side.
It is, therefore, necessary to take care to buy the machines that have been designed to be mounted in position 3 + 3 or 6 in line. To simplify the choice and to have good machines it is preferable to buy a model with a design that allows the assembly for both positions, so if you had to change the headstock or the guitar you can reuse them.
You can choose self-locking tuning machines: a model that prevent the slippage of the strings during the use of the instrument, to maintain the tuning. The assembly of such machines is useful with high draw types, with alternative tunings such as Nashville Tuning or those developed by Michale Hedges in which the strings are tuned above their usual note.
Another very useful technical innovation is the self-lubricating tuning machines that for their design and their materials do not need to be continuously lubricated and therefore they are easier to maintain.
An element to be evaluated is also the gear ratio. The function of this technical trick is to allow to change the ratio between the turns of the key and those that make the string around the machine, to increase the accuracy of the adjustment of the tension of the strings. The most common ratio is 14: 1, but it is advisable to use lower ratios, such as 18: 1 or 21: 1 to have a more precise tuning, even if you need a few more turns.
A fundamental aspect to keep in mind in the choice is the weight of the acoustic guitar tuning machines: six metal machines can weigh down the headstock and unbalance the instrument, making it less comfortable to use: this leads to greater fatigue of the arm making the chords, disrupting the speed of execution and the resistance during the performance. One type of very light tuning machines is those made of carbon fiber: a resistant and light material that is also used for sports equipment and for racing cars.
Composition and materials of the tuning machines
Then there are some machines for the windowed headstock, which are similar to those provided by the classical guitar, but of metallic material instead of plastic.
The tuning machines can also have die-casting or open gear mechanics, depending on whether the gears are hidden or insight.
Generally, all parts of the tuning machines are made of metals such as zinc, steel, and brass. For aesthetic reasons, the surfaces can be plated and glazed with precious metals such as nickel, chrome, and gold. It is important that the worm screw and the gear are made of or covered with the same metal, to limit friction.
As an alternative to the metallic ones, carbon fiber tuning machines are spreading to improve the playability of the instrument: the six metal mechanics give a further weight to the headstock which unbalances the instrument, reducing comfort during execution.
A model of acoustic guitar mechanics that I recommend you are the Heart Sound Guitar Tuning Machines, made of carbon fiber: the whole set weighs only 42 grams and is robust and reliable. Furthermore, the addition of Teflon and other polyamides makes the mechanicals self-lubricating and less subject to wear.
Thanks to their particular design they can also be used both on 3 + 3 and 6 in line models; while the 21: 1 ratio allows greater precision in string adjustment.
The Heart Sound tuning machines are also available with the same features for the Ukulele.
ALWAYS IN TUNE!