Posted on September 25, 2026September 25, 2026 by Dale Phillips The Charles Fox Guitar-Building Method, Part Two The Charles Fox Guitar-Building Method, Part Two by Mark French Originally published in American Lutherie #140, 2020 See also, A Guitar Is Born: Attending Charles Fox’s Hands-On Guitar Making Course by Mark French The Charles Fox Guitar-Building Method, Part One by Mark French The Charles Fox Guitar-Building Method, Part Three by Mark French The Charles Fox Guitar-Building Method, Part Four by Mark French The Charles Fox Guitar-Building Method, Part Five by Mark French The Charles Fox Guitar-Building Method, Part Six by Mark French There are four major subassemblies in Charles’ guitar design. The separately completed rim, soundboard, and back are assembled to create the body, to which the completed neck is then fitted and attached. Given that the design process has highlighted and resolved all their relationships, they can each be considered individually, and created either serially, in any sequence, or simultaneously. Starting the Neck At first glance, Charles’ neck follows a fairly standard design, but it incorporates features that make it work better. One characteristic of Charles’ instruments is that many features and dimensions are shared across different body shapes (“Production Techniques for the Custom Luthier,” AL#110). One of these is the neck. Since most of Charles’ instruments share the same 25.5˝ scale, they can use the same 12-fret or 14-fret necks. The only visible difference is their heel depths, as shown in Photo 1. Even then, there are only two different depths. Become A Member to Continue Reading This Article This article is part of the Articles Online featured on our website for Guild members. To view this and other web articles, join the Guild of American Luthiers. For details, visit the membership page. MEMBERS: login for access or contact us to setup your account.
Posted on August 14, 2026August 14, 2026 by Dale Phillips An Optical Sensor For Detecting String Motion An Optical Sensor For Detecting String Motion by Mark French Originally published in American Lutherie #106, 2011 For luthiers who want to make accurate dynamic measurements on their instruments, it is a challenge to achieve precision for a cost that stays below the pain threshold. Commercial test equipment is readily available, but the prices can be breathtakingly high. There is always eBay, but the selection isn’t always there and the condition of the equipment can be a little sketchy. That leaves the option of making test equipment for yourself. Since the average luthier is constantly making nifty jigs and fixtures, it makes sense to offer a very inexpensive DIY option. I needed a pickup for some projects that require measuring the first twenty or thirty harmonic frequencies of a vibrating string. I’m worried that the pickup response at high frequencies might drop off. All pickups have a window over which they are sensitive, and that window needs to be very short in order to observe the really high harmonics. Single-coil pickups have a shorter window than humbuckers. This makes them more sensitive to higher frequencies and is at least part of the reason that they can sound “brighter.” Also, the presence of a strong magnetic field from a coil pickup might affect the motion of the string. In order to affect the string as little as possible, I wanted to make an optical sensor. Become A Member to Continue Reading This Article This article is part of the Articles Online featured on our website for Guild members. To view this and other web articles, join the Guild of American Luthiers. For details, visit the membership page. MEMBERS: login for access or contact us to setup your account.
Posted on August 7, 2026August 7, 2026 by Dale Phillips “Restomodding” Wall-Hanger Guitars “Restomodding” Wall-Hanger Guitars by Roger Häggström Originally published in American Lutherie #144, 2021 Cheap guitars were made in great numbers all over the world at the beginning of the last century. In Sweden, the driving force behind a burgeoning interest in guitars was the independent church movement. The prevailing sentiment was that every able-bodied parishioner should be able to play three chords on a guitar at prayer meetings and fundraisers (Photo 1). Many of these instruments still exist, mostly in unplayable condition. I have found ways to restore these wonderful old guitars and make them play and sound better than ever. I love the bass-balanced sound of old-style ladder bracing in a small steel-strung parlor guitar. The complex sounds keep me wanting to play another chord. Modern X bracing gives more bass but also less varied tone, in my opinion. Become A Member to Continue Reading This Article This article is part of the Articles Online featured on our website for Guild members. To view this and other web articles, join the Guild of American Luthiers. For details, visit the membership page. MEMBERS: login for access or contact us to setup your account.
Posted on July 21, 2026July 21, 2026 by Dale Phillips A Better Approximation to the Rule of 18 A Better Approximation to the Rule of 18 by Mark French Originally published in American Lutherie #132, 2017 Historically, luthiers often used the Rule of 18 to lay out fretboards for guitars and other fretted instruments. (See “Classic Guitar Intonation” by Greg Byers, AL#47; Big Red Book of American Lutherie Volume Four.) While builders seldom now use the number 18 as the coefficient for calculating fret positions, the name is still used as a shorthand way of identifying the method. While 18 is a very convenient whole number, it is far enough from the exact value of 17.81715 that noticeable errors can accumulate. Still, it is often convenient to use a simple approximation for a long decimal number — many of us have used 22/7 as an approximation to π and 355/113 is even better. With this in mind, you can replace the number 18 with 285/16 and lay out frets very accurately. Let’s see where these numbers come from and why the approximation works. Become A Member to Continue Reading This Article This article is part of the Articles Online featured on our website for Guild members. To view this and other web articles, join the Guild of American Luthiers. For details, visit the membership page. MEMBERS: login for access or contact us to setup your account.
Posted on July 8, 2026July 8, 2026 by Dale Phillips Measuring Resonant Frequencies of an Acoustic Guitar Measuring Resonant Frequencies of an Acoustic Guitar by Mark French Originally published in American Lutherie #143, 2021 Many luthiers track resonant frequencies of their acoustic guitars, often with the goal of meeting some target values. It’s common for the first two resonant frequencies of a full-sized acoustic guitar to be near 100Hz and 200Hz respectively. Some builders use detailed frequency measurements during the build process. For example, Greg Byers described his methods in his 2017 GAL Convention workshop (AL#134). Another good discussion is in Volume 1 of Contemporary Acoustic Guitar Design and Build by Trevor Gore and Gerard Gilet. Resonant frequencies are a function of the ratio of stiffness over mass. Specifically, frequency is proportional to √(stiffness/mass). This simple relationship is harder to apply at higher modes, but it describes the effect of the structure on the lowest modes well enough for us. In practice, it’s easier to reduce resonant frequencies than to increase them. Selectively thinning parts of the top or shaving braces reduces stiffness more than mass, and so tends to reduce resonant frequencies. It’s very uncommon for luthiers to add anything, either mass or stiffness, to their guitars in order to modify dynamic response, though it is certainly a valid thing to do. Trevor Gore is the only one who comes to mind, though there may be others I’ve not heard of. Become A Member to Continue Reading This Article This article is part of the Articles Online featured on our website for Guild members. To view this and other web articles, join the Guild of American Luthiers. For details, visit the membership page. MEMBERS: login for access or contact us to setup your account.
