Hi Fabio,

Thanks for the question. The actual thickness of the top, sides and back is function of the wood strength that you are using. For backs and sides you can start out at about 3/32″ or 2.2 mm to 2.4 mm. This would work for any of the Rosewoods, Cyprus, Walnut, Maple, or other very hard, straight-grained wood. If the wood has a lot of figure you may want to go slightly thicker say to 2.4 to 2.5 mm.

As for the soundboard wood, the variation is even greater. I would say that the range would be from 2.0 mm to 3.0 mm Sitka Spruce could be on the thinner side and the cedars would be on the thicker side. I make classical guitar with Canadian Red Cedar and I make them about 2.6 mm because the cedar is tight grained and very stiff. If using Sitka Spruce I would use a thickness of about 2.2 mm for a tight-grained, vertical grain top.

See the article on tap tuning for more information on top selection and analysis see the article:
http://ultimate-guitar-building.com/guitar-top-analysis/

Your plans look very interesting. I like that they are in digital format. Do you have the plans for classical guitars available in 650 scale?

Regards,
Koichiro

I would have purchased 650mm scale if it was available. I just assumed it was not, I’ll build to 650.

Another thing that I think would have been nice to see on the plans is information about thicknesses (back, sides, top). I purchased plans because I thought they would provide the information needed to build that instrument, it does not.

I’ll keep that in mind when planing my next build.