Posted on June 6, 2024January 17, 2025 by Dale Phillips Questions: Thickness Measuring Tool Questions: Thickness Measuring Tool by Tom Nelligan and R.M. Mottola Originally published in American Lutherie #92, 2007 Georges E. Vougioukalakis from Athens, Greece asks: In my experimentation and research on double-top guitar construction I find a need for an instrument that can measure the thickness of the outermost skin of the top on a fully assembled instrument without damaging the top. Does anyone know of such a tool? I remember a citation of an instrument that was used to measure the thickness of the paint in autos. Tom Nelligan from Olympus NDT/Panametrics-NDT Products in Waltham, Massachusetts replies: Commercial ultrasonic thickness gauges of the sort made by my company (and our competitors) for measurement of industrial engineering materials like metals, plastics, and ceramics will not work on wood, because wood does not efficiently transmit sound waves at ultrasonic frequencies in the MHz range. Pulse/echo ultrasonic gauging is based on very precisely measuring the round-trip transit time of a short pulse of very high frequency sound waves through the test piece. But the high frequency/short wavelength wave front is scattered by the microstructure of the wood, so it is not possible to get the necessary clean echo from the inner wall. Become A Member to Continue Reading This Article This article is part of our premium web content offered to Guild members. To view this and other web articles, join the Guild of American Luthiers. Members also receive 4 annual issues of American Lutherie and get discounts on products. For details, visit the membership page. If you are already a member, login for access or contact us to setup your account.
Posted on June 6, 2024January 21, 2025 by Dale Phillips Another Method for Calculating the Area of a Plate Another Method for Calculating the Area of a Plate by R.M. Mottola Originally published in American Lutherie #70, 2002 and Big Red Book of American Lutherie Volume Six, 2013 There are a number of reasons to calculate the area of the plate of a stringed instrument. The area of a flat plate can be used to determine the volume of the instrument by simply multiplying the area by the depth. This value is useful in the design of electric guitars and basses to determine the weight of the body of the instrument before it is built. This info can aid in the design of an instrument that balances well when hanging from a strap or sitting on the leg. In the design of acoustic instruments, the volume can be used to calculate the nominal Helmholtz resonance of the soundbox, which may be useful in the tuning of the resonance characteristics of the instrument. The technique specified here will work for any arbitrary shape and is both simple and relatively quick. It is the essential algorithm of a CAD script I use, and is based on a computer graphics rasterization technique. Modified and simplified for use with pencil and paper, it yields a good enough approximation of the area of a plate for the purposes outlined above. Become A Member to Continue Reading This Article This article is part of our premium web content offered to Guild members. To view this and other web articles, join the Guild of American Luthiers. Members also receive 4 annual issues of American Lutherie and get discounts on products. For details, visit the membership page. If you are already a member, login for access or contact us to setup your account.
Posted on June 6, 2024January 17, 2025 by Dale Phillips Questions: Crownless Frets Questions: Crownless Frets by James Westbrook and R.M. Mottola Originally published in American Lutherie #89, 2007 Gilles Danis from the Internet asks: I have been asked by a museum to restore an old guitar. It is a rather cheaply made thing from the early 20th century. The frets do not have crowns. They are just thin flat bars on their sides with barbs at the bottom. Do you know of a source for such fretwire? James Westbrook from England replies: I get my bar fret stock from Makoto Tsuruta in Japan. I think there are a few different sizes. His website is www.crane.gr.jp., and his e-mail address is mmm@st.rim.or.jp. The Questions Column editor adds: Nickel-alloy sheets of various thicknesses and alloy composition are available from McMaster Carr (www.mcmaster.com) but they need to be cut into strips for use as bar frets. Sheet metal places or machine shops that have shears can do this cheaply. ◆
Posted on April 21, 2023March 5, 2024 by Dale Phillips Product Reviews: Ameritage Cases Product Reviews: Ameritage Cases by R.M. Mottola Originally published in American Lutherie #68, 2001 and Big Red Book of American Lutherie Volume Six, 2013 Ameritage Cases My friend and mentor Jim Mouradian of Mouradian Guitars is a clever guy. He builds a thoroughly modern electric bass called the Reality. It has a trim upper horn and swoopy waist cut that you would never confuse for a ’50s-styled Fender Jazz bass. But if you were to take just the outline of the Fender and lay it over the outline of Jim’s bass, you’d notice an interesting thing. The outline of the Reality is identical to that of the Jazz in a few places, and in the places where it is different, it is always smaller. Thus Jim’s instrument fits perfectly snug inside an off-the-shelf aftermarket Jazz bass case. This detail gives Jim a lot of options when it comes to cases. Like I said, he’s a clever guy. Those of us who build instruments for which “standard” cases are not available have to have cases custom made. Some builders need custom cases simply because they don’t want their instruments seen in anything less. There are a number of custom case makers. I’d like to share my experiences with one of them. Ameritage Carrying Cases is the musical instrument division of GWW Inc., a manufacturer that makes cases for just about anything. I found them via their website and asked for quotes for four cases for acoustic-electric basses I was building. I knew that custom cases would be needed for these, and I knew they would fit into standard Jazz bass cases but would rattle around inside. This last bit of information turns out to be kind of important. You can look at an instrument case as having two major components — the outer hard shell, and the padding between the shell and the instrument. If a manufacturer has to custom build the shell, then you are looking at one expensive case. But if they can use one of their existing shells, then the only thing that is unique for your case is the padding, and that makes for a more reasonable price. My instruments would fit into the standard rectangular electric-bass case shell. Become A Member to Continue Reading This Article This article is part of our premium web content offered to Guild members. To view this and other web articles, join the Guild of American Luthiers. Members also receive 4 annual issues of American Lutherie and get discounts on products. For details, visit the membership page. If you are already a member, login for access or contact us to setup your account.
Posted on April 21, 2023March 5, 2024 by Dale Phillips Constructing an Under-Saddle Transducer Constructing an Under-Saddle Transducer by R.M. Mottola Originally published in American Lutherie #68, 2001 and Big Red Book of American Lutherie Volume Six, 2013 Piezoelectric transducers or pickups (I use the terms interchangeably) are popularly used to “electrify” acoustic instruments, and are increasingly found embedded in the bridge saddles of electric instruments as well. Manufactured transducers are available from a number of sources, but this article provides instructions for making an undersaddle piezo pickup for a flattop guitar from basic materials. If you know which end of a soldering iron to grab hold of, you can build this pickup. Piezo material will generate an electrical charge when mechanically deformed. There are four types of piezo materials used in the manufacture of instrument transducers: lead zirconate titanate (PZT) ceramic chips, PZT ceramic “bender” disks, polyvinylidene fluoride (PVDF) plastic film, and PVDF coaxial cable. PZT chips find their way into first-generation undersaddle guitar transducers, transducers for various bowed instruments, and manufactured archtop guitar and mandolin bridges. PZT disks consist of PZT material bonded to thin brass disks, and are commonly used for soundboard pickups for flattop guitars and for bridge-mounted pickups for upright basses. PVDF film may be found in all sorts of transducers from undersaddle guitar transducers to under-bridge-foot transducers for bass viols. PVDF coax cable is manufactured just like the single-conductor shielded cable used to make instrument cables, except that instead of an insulating material between the center conductor and the outer shielding braid, we find PVDF material. It is used in manufactured undersaddle pickups for acoustic guitars and is the material that will be used to construct a transducer in this article. Become A Member to Continue Reading This Article This article is part of our premium web content offered to Guild members. To view this and other web articles, join the Guild of American Luthiers. Members also receive 4 annual issues of American Lutherie and get discounts on products. For details, visit the membership page. If you are already a member, login for access or contact us to setup your account.
