Army-Navy Mandolin based guitar

[Mike Sayre]

I was impressed with the volume of a Flatiron pancake-style mandolin, and am considering trying a guitar build using the same (flat top and removable bridge) design, but with a guitar style 16-17 inch body, 1 1/2" thick; probably maple neck, cherry B/S, spruce top. Any ideas about what to watch out for?

[Clay Schaeffer]

You might check out Irish bouzouki and octave mandolin designs. I think I would make it a bit deeper in the body and put some doming in the top to counteract the down pressure on the bridge. Here is an eight string instrument to which some bass strings were added.

[Chuck Morrison]

I was impressed with the volume of a Flatiron pancake-style mandolin, and am considering trying a guitar build using the same (flat top and removable bridge) design, but with a guitar style 16-17 inch body, 1 1/2" thick; probably maple neck, cherry B/S, spruce top. Any ideas about what to watch out for?

Mike,
As the guy who inflicted the Flatiron mandolins upon the world, I guess I should chime in. I've thought about your concept for a few days now, and aside from body & neck scaling issues, I'd suggest you depart from the basic design when it comes to bracing. There were only two braces on the Army/Navy. A transverse brace directly under the bridge and a matching back brace. You could do that, scaling up the brace(s), but I don't think the tone quality would be worth much. Maybe it depends on your tastes and type of music you want to play. To get a more guitar like sound some adaptation of X or fan bracing might be worth trying. The floating bridge makes any of these options feasible.

The original A/N bodies were maple or birch. I used maple and rosewood on the original Flatirons with mahogany necks. I prefer maple necks now, but they are heavier. You may have weight balance issues, depending on materials, tuners, etc. I built the original Flatirons with a dovetail neck joint. The sides extended right up to the cut. The corresponding neck side was cut as closely as possible to that profile. It is an interesting joint to fit. You may want to redesign that joint to make it a bit easier. The neck was also non-adjustable, you may want a truss rod in there.

Well, that's all I can think of at the moment.

[Matthew Lau]

Wow.

I have to say that the Flatirons that I played were nice instruments.