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Questions: 12 String Acoustic Guitar Plans

Questions: 12 String Acoustic Guitar Plans

by John Calkin

Originally published in American Lutherie #85, 2006



Robin Walke of Kent, England, UK asks:

I am looking for construction plans for a 12-string acoustic guitar. The style of instrument I like is either a Guild F Series or the Martin D-12-28. I have looked all over the net without any luck. Any help you can offer will be appreciated.


John Calkin responds:

A couple sources of 12-string plans are: Elderly Instruments (www.elderly.com/books/cats/611.htm) and International Luthiers Supply (www.internationalluthiers.com/instrumentplans.php). However, you could always get a 6-string plan and beef it up a little.

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Questions: 12 String Acoustic Guitar Plans

by John Calkin

Originally published in American Lutherie #85, 2006



Robin Walke of Kent, England, UK asks:

I am looking for construction plans for a 12-string acoustic guitar. The style of instrument I like is either a Guild F Series or the Martin D-12-28. I have looked all over the net without any luck. Any help you can offer will be appreciated.


John Calkin responds:

A couple sources of 12-string plans are: Elderly Instruments (www.elderly.com/books/cats/611.htm) and International Luthiers Supply (www.internationalluthiers.com/instrumentplans.php). However, you could always get a 6-string plan and beef it up a little.

Strings for 12-string guitars have gotten so light that I don't believe much beefing up is necessary. Forty years ago everyone knew not to tune their 12-strings up to pitch, but so many players have insisted on it that string sets have gotten very light. It's probably enough to use a standard brace pattern, but not scallop any braces.

It's common practice to build 12-strings with a shorter scale length and twelve-fret necks, both intended to keep the guitar from torquing out of shape. Huss & Dalton follows both practices. And lest anyone worry about underbracing their 12-string, the steel-string books by Sloane and Young both contain material on morphing their dreadnoughts into 12-string models.

At H&D we've made only a few 12-strings and they were on the smaller CM body but without a cutaway. We made everything heavier on the first one, and I knew before I put it together that it would be way overbuilt. Fortunately it sounded OK, though it was quiet. Succeeding instruments have each gotten lighter until we reached the above formula. The red spruce bracing we use is often very stiff, which might make some difference, but I've also seen some brutally stiff Sitka brace stock. I think I'd use the stiffest stock I could find and use a normal pattern rather than use some random stock and try some extra braces with unknown tonal characteristics. We also left the top a bit thicker, and we left that factor consistent while we varied the size of the braces.

There's also the Leo Kottke school where heavy strings are used but tuned way down, perhaps all the way to C. I have no experience with this but would guess that detuned heavy strings would have about the same tension as light gauges tuned to standard pitch. ◆

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Questions: Bracing Reinforcement

Questions: Bracing Reinforcement

by Jeffrey R. Elliott

Originally published in American Lutherie #91, 2007



François Leonard of Port-Louis, France, asks:

I’m guitar maker in France and I’ve been following and reading articles in American Lutherie since many years. I had recently an order for a 10-string guitar and I’m asking myself how much I need to reinforce the design of the bracing. My bracing is not so different from the one Jeffrey Elliott uses and talks about in his AL#56 article “Shaping the Sound.”


Jeffrey R. Elliott of Portland, Oregon, responds:

My experience is more extensive with 8-string guitars, but I believe the same principles apply. I suggest the following:

Select top wood that is more stiff than you would choose for a 6-string, one with all the characteristics you usually look for, but also with a somewhat extended tap-tone range toward the lower pitches.

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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. ◆

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Letter: Side Soundhole Guitar

Letter: Side Soundhole Guitar

by Marc Connelly

Originally published in American Lutherie #93, 2008

 

Dear GAL Family,

Thank you Cyndy Burton for the exploration of side-ported instruments. It was a terrific affirmation for this most interesting fenestration option. Like Mr. Montelone, at some point I laid my head on the side of my old Martin, strummed, and wondered how to get more of that big wood and bronze sound into my face. I started experimenting with a “side hole” variant, and it changed the way I think about what I am doing — not because it was “better,” but because it was clearly different in a thought-provoking way. In fact, this exercise has finally purged the word “better” from my lutherie vocabulary, and that’s a good thing.

My side-hole instruments (which I call “Atlas”) are from the same plantilla as my front-hole models, so I can make some general comparisons. At first, the Atlas models seemed a bit too percussive and weighted toward the bass. So I made some small modifications in the way I tune the box and tamed the bass. The percussive nature of these guitars is simply a component of getting a more direct blast of wavy air into the player’s face. I have come to like this. Several Atlas owners have agreed it has an appeal and have readily adapted to it.

But a truly freakazoid experience is to stick your left ear in the hole and play! There isn’t a prewar D-45 on the planet that sounds like that! Until I read Montelone’s article, I never even considered the possibility of weakening the side. What was I (not) thinking! None have folded up, but future Atlas models will have some consideration for this possibility.

Fusion jazz player Don Mock owns an Atlas and loves it. Don enjoys having people ask “What’s that?!” Of the folks who play my guitars with some interest in commissioning one, the Atlas is always the first off the rack. But guitar players are an amazingly conservative lot, I find. Selling a side-hole guitar is like selling a blonde guitar. You are either open to them or you are not. It is personally rewarding to watch the tug of war between the conventional and the unconventional. ◆

Photo by Marc Connelly.
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Questions: Jig for Oval Rosettes

Questions: Jig for Oval Rosettes

by R.M. Mottola

Originally published in American Lutherie #97, 2009

 

Greg Pacetti of Fairbanks, Alaska asks:

I’m in pursuit of some kind of jig for oval rosettes.


The Questions column editor
responds:

Probably the single best source of info on cutting oval rosette channels appeared in the American Lutherie article “Making Oval Mandolin Rosettes” by Jonathon Peterson, et al. (AL#41 p. 34, BRBAL4 p. 140). In it, seven builders describe their methods. ◆