Guitar Machine Head Tuner Types Detailed Guide

The tuning machine heads on a guitar are a very important part that can have a huge impact on your experience. Most players are somewhat intimidated by them because of the responsibility they have with tuning stability. How do you choose the right machine head tuner types?

There are 6 main types of machine head tuners used on most guitars, each one with its pros and cons, and unique applications. Not all tuners are created equal, and nor are they all universal.

In this article, we are going to touch on the different types of machine heads. We will investigate how each one is designed to be applied to a special application and serve a special purpose.

Guitar Machine Head Tuner Types

What Are Machine Heads?

A machine head, more commonly referred to as tuning pegs, is a device used to tighten or loosen the strings on an instrument. It’s usually a cylindrical-shaped object with a knob for adjustment. Turning the knob clockwise loosens the string, while turning it counter-clockwise tightens it.

The machine heads serve a very important role, not only are they to adjust tension, but they are also responsible for making sure the string does not slip. If the string should slip, or the gears skip teeth internally, it will go out of tune.

This is a very frustrating experience for a guitarist, as an instrument that won’t stay in tune cannot be played. It’s very important to use high-quality machine heads on your guitar for the absolute best experience.

Types of Machine Heads

There are six types of machine heads, and each one is designed for a different purpose. Some are created to look a certain way, while others are designed for performance. A vintage-style acoustic will require the type that is durable but also looks the part.

Whereas an electric metal guitar will use the type that is sealed and made for performance over aesthetics.

The 6 types of guitar tuners are:

  • Sealed machine heads
  • Vintage open back
  • Vintage closed back
  • Side mounted
  • Staggered machine heads
  • locking machine heads

Let’s take a look at each one and explore how each type benefits the guitars they are mounted on.

sealed machine heads

Sealed Machine Heads

As the name suggests, sealed machine heads are a type of tuner that is completely enclosed. This means that there is no way for dirt, dust, or any other debris to enter the internal mechanism of the tuner.

It also means that all lubricants that were applied at the time they were made are locked in as well by the protective housing.

This is an important feature for guitars that are used in a performance setting. Sealed tuners keep out the elements and are permanently lubricated. This results in a longer lifespan for the tuners and keeps them functioning smoothly for many years.

This is the most common type of machine head used on guitars and can vary in quality depending on the brand that made them.

Styles Of Sealed Guitar Machine Heads

To make things even more complicated, there are two different styles of sealed tuners.

  • Inline
  • Left and right

Inline tuners are all made to face the same direction and stick out on one side of the headstock. It’s next to impossible to mix them up because they are all the same! If your guitar has machine heads all on the same side, then you have inline tuners.

Left and right tuners are not as easy. These are made to have half on one side of the headstock and the rest on the other. These are designed to mount on one side only and cannot be simply turned over to fit on the other.

They are made to work on one side only and so if your guitar is designed this way, you can’t use inline tuners. In the case of a 6-string guitar, this will be 3 left and 3 right.

How To Mount Sealed Machine Heads

Sealed guitar tuning pegs are mounted to the headstock by passing the shaft through a hole that is normally 3/8″ but can vary to 10 mm. A washer and threaded bushing is then passed through the hole in the headstock and fastened to the tuner base to hold it in place.

The bushing alone is not able to prevent the machine head from rotating in the hole, so a screw or indexing pin is used to prevent this. It’s more common to see the screw on the back of the tuner, but pins are used on occasion, depending on the manufacturer.

Machine Head

Once the screw has been fastened to the headstock, the bushing is then snugged up and the sealed tuning peg is mounted.

A nut and washer can be used instead of a bushing. To know what type you have, it’s best to take one off of your guitar and measure the hole in the headstock at the same time.

Vintage Open Back Machine Heads

Open back tuners have been around for many years and were the first in existence. They get their name from the fact that the back is open and there is no protective housing. This allows you to see the gears on the back of the headstock and gives it a more attractive vintage look.

These were very popular on acoustic guitars many years ago, but have since been replaced by sealed tuners. They are still a popular choice on acoustic guitars that have a vintage aesthetic.

The only issue with the Vintage open-back tuners is that they are exposed to the elements, and any dust or abrasive contamination can get caught up in the gears. This can cause premature wear if proper cleaning is not exercised regularly.

Styles Of Open Back Tuners

While the vintage open-back tuners are not used quite as much anymore, there are still a few different styles that can be obtained.

  • Inline
  • 3 per side
  • Gear Ratio

Inline machine heads are still available, but not quite as common. They were used a lot in the 50s and 60s on guitars like the Fender Telecaster. But today sealed machine heads are used instead.

Left and right, or 3 per side tuners are the most common, as most acoustic headstocks use this pattern.

The gear ratio type is a specialty item made by Graph Tech. They have been designed to allow for fine-tuning based on the string thickness. The higher the number, the more precise the tuning will be.

These are great for replacements on vintage guitars like the Fender Stratocaster!

How To Mount Open Back Tuners

open back machine heads

Open back tuners are mounted to the headstock similarly to the sealed type, but there is one main difference.

There is no bushing that is used to keep the tuner in place, instead, it simply gets screwed down to the back of the headstock.

2 screws hold the open back tuner to the headstock. An alignment bushing gets pushed into the headstock hole to keep the shaft straight when the tension of the strings is applied.

The hole in the headstock for open-back tuners is usually 1/4″ in diameter.

Vintage Closed-Back Machine Heads

The traditional vintage closed-back machine heads are similar to the open type, except for a casing that covers the worm screw gears. They use the same fastening method as well as the bushing pressed into the headstock hole to support the post.

Styles Of Vintage Closed-Back Tuners

There are 3 styles of closed-back tuners:

  • Inline
  • 3 per side
  • Plate-mounted

The inline and 3 per side are functionally similar to the open-back vintage style, except for a protective housing over the gears.

The plate-mounted style combines all 3 machine heads per side. Having all 3 tuners on a long single plate prevents them from twisting and adds support. It also only requires 4 screws to fasten the assembly to the headstock.

Each of the gears is covered by a casing to protect them from dirt and debris.

How To Mount Vintage Closed-Back Tuners

The inline and 3 per side vintage closed-back tuners are also mounted to the headstock with 2 screws and an alignment bushing. This is similar to the open-back style as the only difference is the cover.

The plate-mounted assemblies are mostly the same. The plate itself gets screwed to the headstock and supports the tuning pegs.

Side Mounted Machine Heads

Side-mounted machine heads also use a plate to support each tuner and are only really found on classical or flamenco guitars. They are open, so the gears can be seen, which means they are also exposed to dust and dirt.

This design is exclusively 3 in line, with the knobs pointing towards the back of the headstock. Because they mount to the side of the headstock, the tuner posts then sit in 2 grooves to allow them access to the strings.

They are very much vintage aesthetically and are recognized by their plastic knobs. These machine heads are made for nylon strings, so the posts are primarily plastic.

ide Mounted Machine Heads

How To Install Side Mounted Machine Heads

Installing side-mounted machine heads is quite easy. Because they come on plates of 3 inline, you simply put them into their respective holes and install the screws.

A classical guitar headstock has 3 wide grooves that are home to the tuner posts. One side of the post is also supported by the wood, making this an easy installation. The hardest part will be deciding on which style to buy.

Staggered Machine Heads

Staggered machine heads are similar to the sealed type, except they come in a range of different post lengths. These tuning pegs are primarily made for headstocks that are not angled. String trees are also used with them to provide the best force on the strings.

When a headstock is not angled, it can affect the break angle, which is used to apply string pressure on the nut. When there is less of an angle, the string can buzz on the nut slots, which also affects the sound they make. This can also create fret buzz if the break angle is severely compromised.

Angled headstocks apply enough string force against the nut to prevent any odd noise or loss of sound. Staggered tuners help provide more of a break angle when the headstock is straight.

The height of the high E string is normally the shortest, as it is farthest from the nut. As the tuning posts get closer to the nut, they then get taller. This provides enough break angle for each string to perform optimally.

Guitars that benefit from these types of tuning posts are Fender Telecaster and Stratocaster headstocks. When used with string retainers, they fix any break-angle issues that might affect your experience.

If you have replaced your machine heads with a generic brand not know that this change in height is necessary, you may want to verify this.

Locking Machine Heads

The locking machine heads are designed to add mechanical resistance to the tuner post to prevent it from moving. This advantage assures the player that the machine head will not allow string slippage.

They are so effective that the only way to adjust the string tension at all is to loosen the locking mechanism. They are sealed-style machine heads with the added benefit of the locking mechanism.

So not only do they stay sealed and offer long life, but they also add tuning fidelity!

These are not to be confused with Floyd Rose style lock nuts, as they serve a completely different purpose. The locking machine heads cannot be used with Floyd Rose style guitars, as the tuning is done at the tremolo bridge.

But they are great for any guitar that does not use this system. Even a Fender Guitar with a Tremolo-style bridge without a locking nut.

If you have issues with slipping tuning pegs, these machine heads will solve that issue fast!

Machine Head Gear Ratio

Machine Head Gear Cog

Machine heads are designed with worm screw gear cogs. This design is used because a worm screw can resist slipping under the tension of a string. But this means that a gear ratio is needed in order to be able to fine-tune the pitch as well as hold it there.

Every set of machine heads will normally come with a gear ratio of 18:1 with some offering a courser adjustment of 12:1. This means that every tuning post has the same ratio and will require a certain amount of turns to tune your string.

A machine head gear ratio of 18:1 means that you will have to turn the tuning button eighteen times for the post to revolve once. Conversely, a 12:1 ratio means that twelve tuner button rotations are needed for one full revolution of the tuning post.

The larger the number, the more rotation will be needed. But that will also mean a higher quality performance. Brand dependent, of course, as cheap machine heads may not offer the same optimal performance.

Here are some gear ratio ranges that quality brands offer in their machine heads.

BrandGear Ratio Range
Grover14:1 to 18:1
Kluson14:1 to 19:1
Gotoh14:1 to 28:1
Graph TechVariable set 12:1 to 39:1

Do Machine Heads Affect Sound Quality?

Machine heads come in many types, but how do they affect your sound quality? Most of them are made from a form of metal, whether steel or brass, they will resonate. Yes, it’s true that some might vibrate more than others, but this will be negligible.

Choosing machine heads is more about how they look than what they might offer in terms of sound quality. When it comes to performance, as long as they can prevent string slippage and offer accuracy, it’s hard to demand anything more from them.

Conclusion

There are a variety of machine heads available on the market and they each have their own benefits. Knowing which type is good for your guitar is important in order to have the best possible experience while playing.

There are also many great looking types available that are very vintage themed that can work great for even more modern guitars.

Manufacturers are constantly improving their products and new designs are always being released. It’s critical to also make sure to be buying high quality machine heads, as they are one of the more important parts on your guitar.

Machine Head Gears

FAQs

What are die-cast machine heads?

Die-cast is a process of forming metal parts using molds and nonferrous alloys. Die-Cast Machine heads are made from this process, normally in order to get the right size and shape. And because this process is so effective, it also means they are easier and cheaper to make.

Are all machine heads the same?

No, there are 6 types of machine heads on the market that all fit a different role. Some players prefer performance, and so a sealed tuner might be the best fit.

Others may want a certain look, and so a vintage machine head would be the perfect unit. Then there are few others made for certain applications like side mount.

Are all Grover tuners locking?

No, Grover makes many types of machine heads, from locking, vintage to modern. They also make a wide range of machine heads with different gear ratios to meet the needs of today’s guitar players.

You can find any type of machine head in their catalog, with many shapes and sizes.

Photo of author

Don East

My name is Don East, I'm the editor for Killer Rig. I've been playing guitar for over 20 years and have designed and manufactured products like guitar amps, effects pedals, and more. Over the years I have played in many bands and have a deep love for quality gear.I am an electrical engineer and have a passion for music gear, and now want to share what I know with the community!