Modifying the Cumpiano/Natelson classical guitar plan for 10-string?

[Mike Recchione]

I was one of the original members of sawmill creek, but haven't been around in many years - so many that I don't recognize any names anymore...

I have made a few CBGs, and a Saxon box lyre, and am itching to take on my first "real" acoustic project. The CBGs started as the simple, fretless 3-string that everyone builds, but I tried to add sophistication with each new project - first frets, for a cigar box "greek baglamas", then frets and a scarf joint for the headstock on a 4-string "tenor CBG". Now I'd like to build something that actually sounds OK when it's not plugged in.

I've been trying to decide what to build - I want it to be something a little out of the ordinary, but also something that I'd play. One candidate would be to make a 10-string classical guitar (I'd eventually like to tackle a theorbo lute - saw the one George Wilson built in the SMC archives, and developed some heavy-duty covet problems..., but I'm a long way away from being able to make one of those...).

My question is, can I just modify the measurements for the classical guitar that's covered in the Natelson/Cumpiano book to accommodate more strings, or are there other structural changes that I'd need to make to handle the tension of 4 extra bass strings? I was planning to go relatively inexpensive, with cherry sides & back, either cherry or maple neck, and a cedar top. (I'm expecting to have to throw away some wood on this first build...).

If that's not a good way to go, does anyone have any experience with any of the plans that are available online? (There are a number of them out there ...)

Thanks in advance!

[Chris Fournier]

You'll need to do some calculations but 4 bass strings will likely give you some problems as the guitar scale length will mean very low string tension on the bass strings. I have made several 7 string guitars, one a classic and the seventh string was A. I had to order special strings for the low A, higher mass. The body was pretty standard dimensionally but a bit deeper on the bass side. Most 10 strings in the classic involve drone strings, not the 7 string however. I would modify the Nat/Comp guitar and reduce your string count but that is just me. I would encourage you to use a denser wood than cherry, say hard maple at the minimum so that you can have a dynamic instrument, cherry will create a soft mellow tone with little attack as you get aggressive. Good luc!k

[Mike Recchione]

Thanks, Chris, particularly about the suggestion re: maple. You're also making me think it might not be a bad idea to pick up one of the 10-string guitar plans for sale. I expect this project will mostly be a learning experience. I'd really like to tackle something like the Tonedevil A-13 harp guitar next - but I don't think I'm ready to take on a cutaway just yet.

Another project on the list is a Puerto Rican cuatro. Anybody have experience making one of those?