Posted on July 8, 2024May 14, 2025 by Dale Phillips Parametric Solid Modeling Software for Stringed Instrument Design Parametric Solid Modeling Software for Stringed Instrument Design by R.M. Mottola Originally published in American Lutherie #87, 2006 Most folks are awed when first witnessing a Computer Numerical Control (CNC) machine shaping an instrument part. Since such a demonstration makes the advantages of using this technology immediately obvious, a number of people look into acquiring these tools for their own use. A substantial portion quickly loses interest when finding out the depth of complexity of the tools needed to design and build in this manner. Computer Aided Design (CAD) software must be mastered in order to draw the parts. Computer Aided Manufacturing (CAM) software must be mastered in order to specify how the drawings will be utilized in the machining process and to control the CNC machine. And the details of the CNC machine itself must be comprehended before real work can be performed. All of this conspires to lead all but the highly technical and/or highly motivated to the conclusion that these technologies need to be made a lot simpler and more accessible before they can be widely exploited in the industry. Adaptation and use of these technologies can be considered analogous to that of the automobile. When first introduced, the car was something only accessible to those who could understand all of the details of the machine (and repair all the parts, too), but eventually it evolved into a more commodity-like device that is usable with little or no knowledge of its inner workings. This article is an introduction to Parametric Solid Modeling (PSM), an existing second-generation CAD technology that offers potential to bring the benefits of CAD/CAM/CNC to a wider user base. A comprehensive library of parametric models of instrument parts and subassemblies could go a long way toward making these technologies generally accessible. The availability of such a library could render a number of aspects of instrument design to sequences of preparing simple drawings and filling in values in forms. No such library currently exists, but it is possible and likely that one could be developed. Folks working with PSM software in this industry undoubtedly have developed such models for their own use. I have some of my own and will use one as an example of how this technology 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. Members also receive 3 annual issues of American Lutherie and get discounts on products. For details, visit the membership page. MEMBERS: login for access or contact us to setup your account.
Posted on July 1, 2024May 29, 2025 by Dale Phillips Questions: Online Lutherie Info Questions: Online Lutherie Info by R.M. Mottola Originally published in American Lutherie #68, 2001 See also, Questions: Online Lutherie Chat by Cyndy Burton R.M. Mottola of Newtonville, MA responds to the question in AL#67 regarding where to have your lutherie questions answered online: I’m sure you’ll get lots of responses that give specific URLs, but here is some background and a way to find most places where you can ask your questions. The internet is generally considered to have three basic facilities — e-mail, websites, and Usenet newsgroups. There are discussion groups on the topic of instrument making that use each of these facilities. To find those implemented as websites you can use any internet search engine to search for appropriate terms. Typing “guitar discussion” into a search engine will get you a lot of hits. Finding discussion groups implemented as e-mail mailing lists could be tricky, as there are no comprehensive search facilities for such mailing lists. Fortunately most if not all e-mail-based discussion groups have a website too, so the search specified above will find those as well. Although most folks are not familiar with Usenet, it contains probably the single largest collection of topic-specific discussion groups. Rec.music.makers.builders is the grand daddy of all instrument building discussion groups, and is a Usenet newsgroup. You can access newsgroups using special facilities included in any web browser. Or you can go to one of the Usenet specific search engines such as Deja News (http://dejanews.com) and follow instructions there for posting to and reading selected newsgroups. ◆
Posted on June 30, 2024May 14, 2025 by Dale Phillips Construction of the Colombian Tiple Construction of the Colombian Tiple by Anamaria Paredes Garcia and R.M. Mottola Originally published in American Lutherie #90, 2007, Big Red Book of American Lutherie Volume Three, 2004 American Lutherie #82 featured an article and plan for the Colombian tiple by Bogotá luthier Alberto Paredes. This is a companion article to that one, featuring a detailed description of how the tiple is constructed in Sr. Paredes’ shop. The design of the tiple is heavily influenced by that of the classical guitar, but as it was not directly descended from the classical, this instrument has unique characteristics. With its multiple courses of steel strings, the construction of the tiple has to be able to withstand much higher static string tension than a classical guitar. The top is cut from bookmatched spruce, nominally 3MM thick. The two halves are generally cut out on the bandsaw at the same time, as shown in Photo 1. The center seam edges are jointed, first on the jointer (Photo 2). Following machine jointing the top halves are finished up on the shooting board using a hand plane. Note that the halves are simply pressed by hand to hold them down on the board during shooting (Photo 3). Glue is applied to the center seam surfaces (Photo 4) which are then clamped using simple cauls to a flat, waxed gluing board (Photo 5). Once the glue is dry the squeeze-out is stripped off the back side of the top. 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. Members also receive 3 annual issues of American Lutherie and get discounts on products. For details, visit the membership page. MEMBERS: login for access or contact us to setup your account.
Posted on June 13, 2024May 15, 2025 by Dale Phillips Fretboard Slotting with a CNC Router Fretboard Slotting with a CNC Router by John Svizzero and R.M. Mottola Originally published in American Lutherie #98, 2009 Lutherie shops with CNC machines use them for a number of applications, some of which are discussed in the article “Desktop CNC Machines” in AL#77. We (authors Svizzero and Mottola) met at meetings of the New England Luthiers and began comparing notes on our shop-built CNCs. Svizzero’s full-sized machine uses Porter-Cable routers as spindles, and Mottola’s desktop machine uses the Proxxon grinder. We have each been using CNC routers in our own shops for slotting fretboards. By CNC routing standards, fretboard slotting is a slow operation due to the small diameter end mills used (typically .022" to .025"), but in our small shops we have found slotting in this manner to be both cost effective in terms of time and to offer some advantages that other slotting schemes do not. With a suitable CNC machine already in the shop, it is possible to experiment with CNC fretboard slotting with a small investment in tooling and time. Our experiences may help others get over some of the startup problems. 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, 2024May 27, 2025 by Dale Phillips Questions: Guitar Rib Depth Questions: Guitar Rib Depth by R.M. Mottola Originally published in American Lutherie #85, 2006 Mark Korsten of Hastings-on-Hudson, NY asks: The article concerning how the rib depth of guitars should be adjusted when plates are domed was clearly written and illustrated (AL#84). I truly appreciate the insights offered by author R.M. Mottola. Being a neophyte luthier, however, I have what is probably a naive question. How does changing the depth of the guitar’s ribs modify the manner in which the bindings are fitted to the binding ledge? It’s a fairly easy operation to bend the binding when the plates are flat. However, when the depth of the ribs are varied, doesn’t that introduce another plane to the geometry? Do you simply use more flexible, thinner bindings or stronger binding tape to keep things tightly apposed in the ledge? R.M. Mottola responds: Although the doming of the plates means that the side depth of the ribs must be varied so the ribs and plates can be glued, this type of construction has little effect on binding. The ledges can be routed using a router resting on the plate or inverted in a router table. In either case the doming is so slight that the routing can be done just as if the plates were flat. And although the bindings must be bent vertically to accommodate the varying rib depth, the amount is so small as to be inconsequential. ◆
