New Gibson guitars have a reputation for dialed-in, off-the-shelf playability. To fine-tune and assure that highly desirably quality, Gibson has invested in state-of-the-art fret-dressing PLEK machines. The first two arrived at the Gibson Custom Shop in 2006, but as of this year every instrument built by both Gibson USA and the Custom Shop will benefit from the PLEKing process.
The best way to experience the results of the PLEK process is to visit your favorite music retail shop, pull any new Gibson guitar or bass off the wall, plug it in and play. But there’s a lot of history and technical precision behind that instant playability.
PLEK machines are built and sold by A+D Gitarrentechnologie of Berlin, Germany. The machines were developed by musician and guitar instructor Gerd Anke with his partner Michael Dubach, who called their company PLEKTRON when it was founded in 1990. The goal of the PLEK process they created is to guarantee the best possible string action for each instrument. Simply put, a guitar with optimized playability sounds better. The strings do not strike the frets during playing and any intonation problems that may occur due to too-low string action are eliminated. Similarly, action that’s too high is also a thing of the past with PLEKing.
The PLEKing process is done by CNC (computer numerical control) machines, which use microprocessors to perform their tasks. That doesn’t mean human craftspeople are excluded from this process. The PLEK machine is ultimately a tool to reduce variances between guitars, which allows Gibson’s expert builders to do their jobs more efficiently.
At Gibson’s USA plant and Custom Shop, PLEK machines are located on the former sites of the fret filing departments. Every guitar is adjusted and set — that is, leveled and dressed — using the machines. The PLEK devices are remarkably self-contained: glass boxes with armatures and other mechanisms to run their cutting tools and measuring devices over the guitars. Gibson has created software templates for every model, and each machine takes about 10 minutes per guitar to work its magic.
Gibson’s first PLEK machines were initially used only for the Vintage Original Spec series, but the accuracy of their fret and nut profiling made them an immediate hit. They are the ultimate fret filers. Gibson makes custom braces to seat the guitars in the machines. The truss rod on each guitar is adjusted prior to being placed in a PLEK machine by using the STS module, a string tension simulator that supplements the PLEK machines. Then the guitar enters the PLEK device and the machine simulates the string tension again while scanning the frets. The machine’s on-board computer takes a 3-D graphic look at the fretboard surface, including the simulated position and height of the strings.
The machine’s operator uses a Virtual Fret Dress menu to determine how much needs to be cut off from each fret and to set the fretboard radius and amount of fall-off suited for the instrument. The graph allows the operator to see the height of each fret, how high each fret will be after processing and — pre-PLEKing — where fretboard buzzes could occur because of frets being too high or too low.
When all the parameters for processing are determined, the frets and nut are cut to those parameters. The PLEK machines continue to simulate string tension as they adjust and file the frets and trim the nut. The machines can peel off just a thousandth of an inch if that is all that’s required.
When the PLEK machine has completed its cycle the guitar rejoins the manufacturing line and all that’s left is to hand polish the frets to a high gloss in the neck prep department.
Gibson’s PLEK machines also provide an added value for customers, since the aftermarket cost of a guitar’s ride on a PLEK machine at a repair shop can be as much as $300.