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Chalk-fitting Guitar Braces

Chalk-fitting Guitar Braces

by Stephen Marchione

from his 2017 GAL Convention workshop

Originally published in American Lutherie #140, 2020



First, have a plan. Know what you’re making. It seems like an obvious thing, but sometimes people start a guitar without a good idea of what the brace layout will be. When I design a new model, I’ll often get a piece of aluminum flashing and lay out a bracing template. If you’re building an historical model, you can transfer the blueprint to a template of aluminum or plexiglas. This gives you a clear idea of what your braces are supposed to be doing, and it lets you be sure that the braces end up where they were designed to go. Photo 1 is a closeup of one of my bracing templates. I use the little holes to make pencil marks on the soundboard.

On a classical guitar, a lot of builders push the big harmonic bars down into the solera, or dished workboard. But that can cause distortion of the top. Even on a Spanish guitar, I take the time to chalk-fit the brace. That gives a better structure with less stress. I highly recommend it.

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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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