What Is A Locking Nut?

If you’ve looked into guitars with tremolo systems, you might have heard about a locking nut and wondered what that is.

So what exactly is a locking nut for a guitar?

A locking nut, which is just one part of a larger tremolo system, clamps a guitar’s strings in place at the nut. Used in conjunction with a locking bridge tremolo system, a locking guitar nut allows players to bend strings for dramatic effect and be sure the strings will return to tune when finished.

Let’s look into what a locking guitar nut does, how you use one, and why players from Eddie Van Halen to Joe Satriani to Dimebag Darrell have made a trem system with a locking nut an integral part of their sound.

Before we go any further, though, a note on terminology. In music, tremolo refers to a rapid change in volume over time, while a rapid change in pitch — which is what the systems in question here were designed for — is technically vibrato.

But when Leo Fender released the Stratocaster, he called the system a tremolo and the name stuck. We’ll use tremolo throughout, but music pedants can now rest assured that more people know the difference.

And anyway, the kinds of sounds we’re concerned with here don’t have much in common with the shimmery dips and swoops associated with those terms. Instead, we’re talking about the kind of players who took the string bending effects of the Stratocaster’s tremolo and gave rise to the phrase “whammy bar.”

What’s The Purpose Of A Locking Nut On A Guitar?

Players like Jimi Hendrix and Ritchie Blackmore became guitar gods with their use and abuse of the tremolo. Think of Hendrix’s iconic rendition of the Star Spangled Banner at Woodstock to picture how the trem.

Even he wasn’t the first, though. Some credit guitarist Lonnie Mack, who had a hit in 1963 with the song “Wham!” with the origin of the term whammy bar, thanks to his use of a Bigsby vibrato unit — for some reason, Bigsby knew the difference between tremolo and vibrato — to bend strings.

Inspired by these players and more, a guitarist named Floyd Rose used the trem on his Stratocaster with wild abandon, but found to his chagrin that when he let go of the whammy bar, his strings didn’t return to the proper tuning.

After some trial and error he realized it was because the strings were slipping out of place at the nut when he used the tremolo system, which meant they changed length. As the length of the string is what determines the pitch, they strayed out of tune.

He created a device that would clamp down over the strings at the guitar’s nut, keeping them from slipping. That, in conjunction with a tremolo system that locked the strings firmly at the bridge, created a system that stayed in tune, no matter how much a player pulled on the whammy bar.

That system, called the Floyd Rose Double Locking Tremolo, has been installed on millions of guitars since then. It’s become an integral part of the sound of whole genres, as the new mechanism unlocked new expressive possibilities for players.

Suddenly, just about anyone could pull off a Hendrix-esque divebomb and then go right back to playing in tune.

Other systems followed suit in the late 1970s and 1980s, including from Kahler and Steinberger. While most used different methods of attaching strings at the bridge, all ended up using a similar locking nut setup.

How Does A Locking Nut Work On A Guitar?

The reason the locking nut helps with tuning stability has to do with how tremolo systems like the Stratocaster’s work. The strings are fed through a hollow block and up into the bridge and over the saddle, then routed to the tuner.

The block the strings attach to is linked with springs to a claw that is mounted to the guitar. The distance of the claw to the body and the number and strength of the springs used all affect how the system feels.

When the player pushes the trem bar down, it lifts the back end of the bridge and lengthens the string slightly, raising the pitch. Depending on the setup, pulling on the bar can lower the pitch, as well.

But because you’re pulling on the strings, you run the risk of the string not returning to its original position in the nut when you let go.

The locking nut is a pretty ingenious solution to this problem. You’re no doubt familiar with how a standard guitar nut looks, with open slots for the strings to sit in.

A locking nut has slots, but instead of being open for the string to sit in, the string sits between the slot and a locking collar. There are three collars on each locking nut — each holds two strings.

The string goes through the slot and into the tuner. When the string is tuned, you use an Allen wrench to tighten the locking nut.

This video shows what goes into installing a locking nut.

How To Use A Locking Nut On A Guitar

One thing to note: You really need a locking bridge and a locking nut together for the system to work, so we’ll run through the entire process, but we’ll mostly focus on the nut.

This process also just explains the process for replacing one string. Because of the way they’re set up, Floyd Rose tremolos should have strings changed one at a time, otherwise you might need to adjust the tension of the setup.

• Install the string in the bridge. For a Floyd Rose tremolo bridge, you normally need to clip the ball end off the guitar string, then slide it into the saddle. Other locking systems retain the original ball end of the string.
• Lock the string in place. A 3 mm Allen wrench locks the string into the saddle.
• Install the string in the tuner. From there, the string goes between the top and bottom parts of the locking nut and into the tuner.
• Tune and stretch the string. Bring the string up to pitch and then stretch it, just like on any other string installation.
• Lock down the nut. When you have both strings tuned, lock down that clamp with a 3 mm Allen wrench and move on to the next.

What’s The Difference Between A Locking And  Regular Guitar Nut?

Something you need to know when installing strings on a guitar with a locking nut: unlike on a guitar with a regular nut, you can’t use the tuners to fix out-of-tune strings.

When putting on new strings, you have to tune the strings before tightening the clamps, because once you tighten them, the string length is locked and moving the tuner won’t do anything. To fix any small changes in pitch on a guitar with a locking nut and a locking tremolo, you use the fine tuning adjustment knobs at the bridge.

The way to set up a fine adjustment bridge is beyond our scope here today, but they’re important, and it’s also important to remember not to use the tuners when the locking nut is clamped down, or you risk breaking a string.

What Guitar Players Used A Locking Nut?

If all of that sounds like an awful lot of work, you’re absolutely right. But is it worth it?

That depends a lot on who you are and what kind of music you play. When the Floyd Rose tremolo system was being developed in the late 1970s, a whole new genre of music was emerging.

Hard rock was becoming heavy metal, and while the virtuosos of the late 1960s, like Hendrix, used a standard Stratocaster tremolo, that wouldn’t be enough for some of the 1970s guitar gods.

While Van Halen’s seminal solo on Eruption actually was recorded using a Strat trem, by the 1980s, he had started using a Floyd Rose trem system with a locking nut to make possible the divebombing pitch bends he became famous for.

He played other locking trem systems also, always after the best combination of tuning stability and wildly expressive string bends from whatever he used.

Other guitarists, too, found that a tremolo system with a locking nut offered them entirely undreamed of sonic possibilities. Some, including guitarists like Joe Satriani and Steve Vai, found success through their virtuosity, playing lead lines and solo licks that sound completely impossible, with fast runs followed by hard bends from the whammy bar.

A song like Satriani’s Surfing with the Alien is an example of what some of them used a tremolo with a locking nut to create.

Those players in turn influenced musicians like the late Dimebag Darrell from Pantera, who combined whammy bar divebombs and harmonics with a much darker sensibility, but whose sound wouldn’t have been possible in the same way without a locking nut tremolo system.

Conclusion

While locking nuts and the matching tremolo systems are most closely associated today with metal, they’ve been used by players from a whole range of other genres, too.

The reason is fairly straightforward: Anyone who has played much with a standard trem system knows that tuning stability will always suffer a little bit.

A locking nut gives players the chance to use the tremolo bar however they want with the confidence that when they let go, everything will be just like it was.

James Kelly

I’ve been a musician, particularly a guitarist, for more than 25 years. I love writing about guitars, gear, recording, music in general and more.