Posted on July 6, 2026July 6, 2026 by Dale Phillips Fretboard/Top Plate Geometry of the Flattop Guitar Fretboard/Top Plate Geometry of the Flattop Guitar by R.M. Mottola¸ Originally published in American Lutherie #111, 2012 The geometric relationship between the fretboard of the flattop guitar and the top of that instrument is an interesting one, if for no other reason than that a number of the critical dimensions of the instrument such as action and bridge height are affected by it. The geometry of these components is also the source of many technical questions from luthiers attempting to make design departures from conventional instruments, and from those who are simply curious about how all this fits together. This article will discuss the topic using basic examples from conventional instruments. The math will be presented for readers who want to make use of it in their design efforts. Diagrams and textual descriptions are also included, and wherever possible I’ve attempted to discuss the practical ramifications of some typical approaches to this aspect of guitar design. This latter part is generally limited to the basic mechanics of how the parts of the instrument fit together. Although it could be fruitful to widen the scope here to include discussion of general mechanics and acoustics of the instrument, I am not dwelling much in these areas. There is enough to cover just discussing the geometry and assembly considerations. To begin, I’d like to introduce some basic concepts and terminology. Some of these concepts are both generally understood and are described using standard terminology. Terms like bridge height, action, and neck angle are familiar, but let me quickly define each of these as they are used in this article. Bridge height is the nominal height of the bridge from the top of the guitar to the top of the saddle at the instrument’s centerline. Neck angle is the angle between the nominal plane of the top and that of the surface of the neck shaft that contacts the underside of the fingerboard. A positive neck angle means the neck is angled toward the back of the body. Action is the height of the strings above the fret crowns. More specifically (as used here), it is the height of the nominal string-bottom plane over the nominal fret-crown plane. 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 June 25, 2026June 25, 2026 by Dale Phillips Beyond the Rule of 18: Intonation For the 21st Century Beyond the Rule of 18: Intonation For the 21st Century by Gary Magliari and Don MacRostie from their 2011 GAL Convention lecture Originally published in American Lutherie #116, 2013 Don MacRostie: I wear a couple of hats. I do product development with Stewart-MacDonald and build Red Diamond mandolins. This is Gary Magliari, the creator of the intonation system we are going to discuss today. We started working on this about five years ago after Gary showed it to me at the Newport Guitar Festival. His method really seems like a benefit to me, and I think it’s time to make everybody aware of what he’s done. I believe there are a lot of little things I can do as a builder to make a good or great, or whatever you want to call it, instrument. Things like using glues and woods that have better acoustic properties, tuning those woods, and applying finishes that improve the output create a better instrument. These are little things and if you leave one out, it can still be a good instrument. 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 June 11, 2026June 16, 2026 by Dale Phillips Experiments in Audio Spectroscopy Experiments in Audio Spectroscopy by John C. Moore Originally published in American Lutherie #80, 2004 and Big Red Book of American Lutherie Volume Seven, 2015 R.M. Mottola’s interesting article in American Lutherie #70 (Big Red Book of American Lutherie Volume Six) described the use of audio spectroscopy, with a simple home setup, for the analysis of bass guitars. I had read about a spectrum comparison of a Martin D-28 with a Kaman AA 14-4 in An Introduction to Scientific Guitar Design by Donald Brosnac, and have always been intrigued with the idea of capturing in an objective way the “quality” of the sound of different acoustic guitars. Also, my experience has been that seeing colors of nature is enhanced by having tried to paint them, and tasting beer is enhanced by having brewed some. I felt that analyzing sounds from a guitar would heighten the senses here as well. When I read the Brosnac book, written in 1978, the equipment utilized for the guitar comparison sounded exotic and expensive, and certainly beyond the capability of the casual hobbyist. In Mottola’s article, it was clear that the technology of the PC had brought the potential for such experiments within reach. In fact, I already had hardware that could get me started: a digital camcorder that I could extract wave files from and a Sony Vaio laptop. So I decided to have a go at some audio trials. 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 May 20, 2026May 20, 2026 by Dale Phillips Testing Threaded Inserts Testing Threaded Inserts by R.M. Mottola Originally published in American Lutherie #101, 2010 Threaded inserts are used in bolt-on acoustic guitar necks, in the style of neck joint popularized by Taylor guitars. An example of a butt-joint neck heel with threaded inserts is shown in Photo 1. I have posted instructions for constructing this style of neck joint on my lutherie info website and not long ago received an e‑mail message from someone taking me to task for the type of threaded inserts specified there. For years I have used self-tapping machine screw threaded inserts and have had good success. But the writer pointed out that these inserts were “not for wood” and so I thought a test of these and other types of threaded inserts would be an appropriate thing to do. There may be better inserts than the ones I was using, and testing is the only way to find out. What I wanted to discover was how strong the hold of the insert was on the wood into which it is inserted. 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 May 13, 2026May 13, 2026 by Dale Phillips Still Voicing, Still Dreaming Still Voicing, Still Dreaming by Dana Bourgeois Originally published in American Lutherie #127, 2016 and Big Red Book of American Lutherie Volume Six, 2013 Dana Bourgeois builds acoustic guitars in what could be considered the Martin tradition. His association with Martin, Schoenberg, Paul Reed Smith, and Bourgeois guitar companies, not to mention his solo building career, has given him the opportunity to voice thousands of flattops, which in turn has given him as deep an understanding of the process as (perhaps) anyone alive. Dana has also been writing and lecturing about lutherie for many years. In August of 1997, he presented a seminar on voicing the guitar at the American School of Lutherie. This article is an adaptation of that presentation. Comparing it with Dana’s lecture at the 1990 GAL Convention (published in American Lutherie #24, and Big Red Book of American Lutherie, Volume Two) shows many similarities, sometimes word for word. This is often the mark of a teacher who has been presented with no reason to change his thoughts. On the other hand, there are major changes in his voicing procedures, demonstrating that none of us reach the end of our evolution as luthiers. 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.
