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  #1  
Old 06-18-2013, 02:54 AM
terrybuddell terrybuddell is offline
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Default Larson brothers truss rod design

Hi Everyone
terry here, havn't posted for a while but have become intrigued with The Larson Brothers guitars and designs and I am trying to track down some extra information that will help me to build a Martin Style 00 or 000 guitar. Firstly I have been trying to track down a drawing with dimensions or a plan that I can buy for a Larson Bros guitar but cant seem to find one. Secondly there seems to be several designs that incorporate a special tubular truss rod that doubles as a neck setting device(? )adjustable at the rear of the body by a nut? Am I way off the beam here guys or is that right? Also I believe Maurers had a slightly curved top and back ( built under tension or so I have read ) Is this correct and if it is, any ideas on the radius of the curve? I believe that the braces were built from a spruce/mahogany/spruce laminate which allowed a thin top to be used from Adinorack /red spruce? Its a big ask but I'd be fully appreciative of any info or to be redirected to sites /books or the like about thes fabulous guitars and what makes 'em tick..Thanks in advance terry.
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Old 06-18-2013, 06:12 AM
Haans Haans is offline
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You can check my website for some general info...

http://www.brentrup.com/index.html

The "adjustable" rods in the Prairie State instruments were probably more to keep the neck from pulling out, and to keep the neckblock from rotating. I have been using two CF tubes instead of the steel rod down the center, and splayed them out to buttresses about 3" out at each side of center at the rear of the ribs. Makes repairpersons happy too!
I know of no plans for a Larson. I found some dead on center photos, scaled them up, and printed them out.
Tops were built "under tension", and I use a flat top, bend it over a curved set of ribs. I use a cylindrical radius of 10' on the top, and a compound radius of 10' on the back. Larsons may well have been more. I do use red spruce.
I am not sure Larson tops were that thin, mine are fairly normal thickness. I am not sure they used mahogany, rather harder woods like BRW, and I know they even tried steel on a few. I use Wenge.
I do have a book somewhere on Larsons, and here is a good website for photos...

http://www.larsonbrothersguitars.com/

Hope this helps...
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Old 06-18-2013, 08:26 AM
maurerfan maurerfan is offline
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Here's an excellent restoration thread posted by luthier david eichelbaum on a 1929 Larson Prairie State showing the tone tube set-up ..

http://theunofficialmartinguitarforu...n#.UcBrSLHD-1s

One of the pics of the end-block ..



Here's a pair of Larsons, the one on the left showing the tube ..



They certainly were innovative ...
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Old 06-19-2013, 04:39 AM
Dan Miller Dan Miller is offline
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Just out are these plans for a Wm. Stahl built by the Larsons from the Guild of American Luthiers:

http://www.luth.org/images/plans/pl66.jpg

Accompanying article is in American Lutherie No. 112.

I am in the process of building my first guitar from these plans.

Dan
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Old 06-19-2013, 05:12 AM
Haans Haans is offline
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Thanks for the info, Dan!
Ordered out of curiosity...
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Old 06-19-2013, 06:39 AM
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Tim McKnight Tim McKnight is offline
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Unless I overlooked it the plans don't seem to depict the cylindrical arch in the top plate. Haans weren't most Larson's built with that unique cylindrical arch?
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Old 06-19-2013, 07:07 AM
Haans Haans is offline
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Tim, I believe they were built with a compound arch. I don't use it for two reasons.
It's too much work to do the dovetail with a compound arch to the top that is that drastic. More importantly, I feel a straight top along the grain adds to the strength in that direction. Granted, tops tend to pull up a bit under string tension, but that is mostly behind the bridge. No doubt the tone tubes help there too.
There was a lot of talk a while back about "modified" guitars, Martins and Dreadnaughts. I guess I build a "modified" Larson. Also use triple tone bars and many other details that Larsons didn't. I think you will agree that it is the nature of the game to want to add your own ideas to designs. After all, just about all instruments built today are "modified" something or other...
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40's guitars., larson brothers, maurers. martin

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