The secret of the PLEK machine

What is a PLEK machine? What does a PLEK machine do? Is the PLEK machine worth it? There are lots of questions out there regarding this machine, and even more bad answers. Who in 2021 would believe that the internet would be rampant with mis-information? The PLEK machine is a complex tool, and I will attempt to dispel some of the mystery surrounding it. Here goes nothing!

A PLEK machine is, quite simply, a tool. It’s primary function is fretwork: fret leveling and crowning, planing and truing fretboards, along with a host of other functions. It also works as a diagnostic tool, as it can “see” things on your guitar that the human eye cannot detect, and can help us diagnose problems. It is a fantastic machine that allows us to set up your guitar with extreme precision. (We describe the PLEK process in detail here and here.)

BUT! The PLEK machine is not an easy-bake oven – one can’t just dump a instrument into the PLEK, push a button, and out pops a perfect guitar. What happens before the guitar goes into the PLEK, and what happens after the guitar comes out of the PLEK is arguably more important than what happens while the guitar is in the PLEK machine. The PLEK’s part of the guitar setup is crucial, but the guitar tech’s involvement with the instrument is vital.

A little history: Aaron and I have worked on thousands of guitars, and have years of experience with fretwork with and without the PLEK machine (at San Francisco Guitarworks, Fodera Guitars, and now in our own shop). We’ve done fretwork just on a bench, which requires a lot of skill and intuition, as there’s no accounting for how the neck is going to move once it’s under string tension. We also have years of fretwork experience on our own neck jigs, which is a more accurate way of working, but still doesn’t account for how a neck will move once the truss rod is adjusted.

Leveling a fretboard by hand utilizing our neck jig.

After doing fretwork on thousands of guitars by hand, we were prepared to invest in a PLEK machine of our own. And let me tell you: the PLEK process is superior in every way. It’s more accurate, more controlled, and removes the need for guesswork. It levels the frets knowing exactly the shape of the neck under string tension. We can program in a perfect radius or compound radius, and even dictate how much fall-away we want in the upper registers. It only removes the minimal amount of material out of the frets. Our fretwork may have been impeccable before the PLEK, and now it is without question even better.

But we’re not just sitting around drinking coffee and letting the machine run the shop. The PLEK is a process, and we are involved in every step. Every guitar that comes in receives a thorough examination, and based on our extensive experience, we can tell when a guitar is in need of fretwork. Once the guitar is in the PLEK, the machine doesn’t do everything for us: we take careful measurements, adjust the truss rod, diagnose problem areas, make informed decisions, and program the PLEK to do our bidding.

Taking measurements to enter into the PLEK program.

And yes, we occasionally have to deal with problems. Sometimes the guitar is too far out of spec, and can’t be processed by the PLEK. The neck can be overly warped, the frets can be too low, the truss rod can be non-functional, frets may be loose and improperly seated, and the scale length can be incorrect. The PLEK isn’t sentient (yet!), so it takes a skilled luthier to be able to make judgement calls. Sometimes what initially appeared to be a simple fret level can turn into an huge ordeal. We wouldn’t have been prepared to deal with these issues if we hadn’t worked on so many guitars before receiving the PLEK machine.

Screenshot of an initial PLEK scan. The orange line indicates the plane of the frets, the green line indicates where they should be. This is WAY of of spec and can’t be leveled by the machine – it needs to be refretted.

It can take as little as five minutes to get the guitar ready to go in the PLEK, and sometimes it can take half an hour. Every guitar is different, and each one presents unique challenges. Even though it physically taxing, I’m glad we spent all that time working on guitars by hand, because it makes us better PLEK operators.

The PLEK process, once the guitar is prepped and the machine is programmed, is usually pretty quick: between five and ten minutes.

After the PLEK has leveled the frets is where the luthier’s skill really comes into play. The frets will have machining marks on them, and they have to be sanded and polished out. Then the guitar needs to be properly set up, based on the parameters the operator had put in the PLEK earlier, and the customer’s preferred action. An unskilled person could very easily make the PLEK completely pointless: they could ruin the accuracy of the fret leveling by sanding/polishing the frets incorrectly, or do a bad job setting the guitar up. What’s the point of the PLEK process if the actual process part is bungled?

Post PLEK frets, sanded and polished. Shiny!

We take great care in our post-PLEK work. We’ve developed an efficient and accurate way to sand and polish the frets, and our setup work is rigorous. We usually spend about an hour on your guitar after it comes of the PLEK. We’ve done this thousands of times, and each time we take careful measurements and play test every guitar, to make sure you’re getting the best playing guitar you’ve ever laid hands on.

Adjusting the action on a… 7-string Telecaster?

THIS is the secret of the PLEK machine: it isn’t just a machine – it’s a process. As a guitar tech/luthier, I can tell you that it’s absolutely worth it. It’s a far superior way to do fretwork – I’ve done more fret levels and refrets by hand than I can count, and the PLEK process is infinitely better. (There’s simply NO way that a tech can do as good of a job by hand, no matter how skilled they are.) Sure, it’s also faster, but the total time that we spend on your guitar, from getting it into the PLEK to finalizing the setup still usually takes around two hours. As a player, it’s a HUGE step up. Notes ring out clearer, big bends don’t choke out, and yes, the instrument sounds better when it’s properly setup with flawless fretwork.

Is the PLEK process worth it to you? Most places in the U.S. charge between $200-$300 for a PLEK fret level and setup, which I believe is a small price to pay to optimize your instrument. EVERY guitar can benefit from getting PLEKed, even if it’s a super expensive custom shop guitar. Many guitar factories bang out hundreds of guitars a day, and there’s simply no way they can get the fretwork to an accuracy of .01mm(.0004″) like the PLEK machine can. Whether your guitar is a brand new Gibson Les Paul or a beat up pawn shop Squier, your guitar will play a million times better after a PLEK level and proper setup.

The PLEK machine is a complex tool, and it’s impossible to explain it in every detail here. But we are happy to answer any questions you have, and time permitting will gladly give you a demonstration. Feel free to drop by the shop anytime and check it out!

Aaron explains the PLEK process to Ian Neville (of Dumpstafunk).

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