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Questions: Single Fretting Fixture

Questions: Single Fretting Fixture

by Tim Shaw

Originally published in American Lutherie #101, 2010



Mark French from West Lafayette, Indiana asks: Do people ever make a single fretting fixture and just pick off whatever section they need for a specific type of instrument? I started with a 25.5" scale length and added some frets to bump it up to about 34.07". It looks like I can use this set of positions to find fret spacing for everything from a bass to a mandolin.


Tim Shaw from Fender in Nashville, Tennessee responds:

You could also use this for both medium-scale bass, which is usually 32", and short-scale bass, which is typically 30" or so. Since Leo Fender had the 25.5" scale first, I don’t know if he actually “added” frets to come up with 34", but that was certainly possible on the prototype. The shorter Fender scales were also probably started by lopping frets off a standard neck.

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Mechanical Compliance for Soundboard Optimization

Mechanical Compliance for Soundboard Optimization

by David Hurd

from his 2006 GAL Convention workshop

Originally published in American Lutherie #90, 2007



People say, “You’ve got to make fifty or a hundred guitars before you get it right.” That makes me crazy. I feel that if you can do the carpentry of putting an instrument together and have idea of what it should look like, you can get 80% or 90% of the way there in terms of top optimization with a mechanical compliance approach.

I build many sizes of guitars and ukuleles using different top woods. I have developed an easy method of testing the compliance of a top, that is, how far it flexes under a given force, with a simple fixture. Being able to measure and compare the compliance values has proved to be a very useful thing in optimizing these soundboards for the best sound and stability when I graduate the edges of the tops and carve the braces.

After building and measuring many instruments, I have developed a mathematical model that does a very good job of estimating what the target compliance measurements should be for a given instrument size and string tension. I have integrated the model into a spreadsheet which you can use by plugging in just a few simple measurements.

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The MacRostie Mandolin Deflection Jig

The MacRostie Mandolin Deflection Jig

by Don MacRostie

from his 2004 GAL Convention workshop

Originally published in American Lutherie #94, 2008



The mandolin world is small enough that if you’re even thinking about building one, you probably already know who Don MacRostie is. Don is an inventor, and he’s done more for Stewart-MacDonald than we will ever hear about. He’s been making Red Diamond mandolins for two decades now. At the 2004 GAL Convention Don discussed one of his research tools and told us how he applies it to his construction process to make the sound of his finished instruments more consistent and predictable.

— John Calkin


At the GAL Convention in 2001, Charles Fox floated the idea of teaching a mandolin building class at his American School of Lutherie. As a result, I taught a two week class, building A-style mandolins from scratch. The only thing we started with was thickly precarved oversize tops and backs. Everything else we made totally from scratch. It was a great experience.

Peggy Stuart, a student in the class, documented the experience in a series of American Lutherie articles (AL#75–AL#79). Tim Olsen asked me to demonstrate and explain the plate-deflection machine we used in the class at this convention, so that’s why we’re all here.

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Violin Setups, Part One

Violin Setups, Part One

by Michael Darnton

from his 1990 GAL Convention lecture

Originally published in American Lutherie #35, 1993 and Big Red Book of American Lutherie Volume Three, 2004

See also,
Violin Setups, Part Two by Michael Darnton



Setups represent one of the most important aspects of violin work. They are the most changeable part of a violin and can make the difference between a customer liking or hating a violin. People who do setups for a living in large shops do a lot of them — countless numbers of bridges, pegs, posts, and nuts. If you’re making one or two or twenty instruments a year you’re not going to be doing many setups. For the people who do those things everyday, it’s a very specialized art and they have very rigorous standards. With that in mind I’m going to try to communicate to you some of those standards, along with some actual “how-to” hints.

Tools

A bench hook (Photo 1) is simply a piece of wood that has a strip nailed to the bottom on one end and a strip nailed to the top on the other end. It hooks over the front edge of the bench and gives a stop to work against. On the under side of my bench hook I’ve glued a piece of sandpaper (Photo 2). If a tiny, thin piece of wood needs to be planed thinner, I flip over the bench hook and use the sandpaper as a traction area.

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Geometric Design of the Stradivari Model G Violin, Part One: Mold and Template

Geometric Design of the Stradivari Model G Violin, Part One: Mold and Template

by Robert J. Spear

Originally published in American Lutherie #93, 2008

see also,
Geometric Design of the Stradivari Model G Violin, Part Two: f-holes by Robert J. Spear
Geometric Design of the Stradivari Model G Violin, Part Three: The Scroll by Robert J. Spear



I have little doubt that artists, artisans, and architects of the Renaissance and Baroque used some system of guidance for their drawings that was based on the knowledge of geometry and the use of straightedge and divider. I began my drawing adventure almost five years ago by following the guidelines for the geometric design of the Model G in Sacconi’s book and soon discovered errors. Even so, I was convinced that it would be worthwhile to use a classical Cremonese approach based on geometry because I wanted to see if I could integrate it with Hutchins and Schelleng’s scaling theories used for the New Violin Family. While the acoustical aspects of the exercise are not germane here, I worked to realize a design system that would essentially produce a second generation of octet instruments close to a classical Cremonese violin in the style of the Model G Stradivari. My goal was to impart a greater uniformity to the octet family’s models, but to keep this article within bounds I have confined my remarks to the violin.

There are those who question whether geometric design really played an important role in violin design and suggest that the model outline could be designed freehand. Others allow that some sort of geometrical or proportion scheme was used, but that it was not based on the golden section. A few ask why one can’t just get a good photo of a good model and enlarge or reduce it at the local copy center. You can (and I did at first), but because strange things start to happen in the larger and smaller instruments during the scaling process, straight scaling does not hold up. Still others, including Sacconi, stress that the eye was the final arbiter of any design, no matter how it was derived. I will attempt to address all of these points in this series of articles.

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