Top Thickness.

Bohemian

I have several sets of plans from a variety of sources for Selmer/Maccaferri and Favino style guitars.
None have the same top thickness .

For those of you working on, working with, selling, repairing or building , what is a common, reasonable, average thickness given that the top is spruce.

Thanks.

Craig Bumgarner

Thickness can vary considerably from one guitar to the next and for spruce, you might see thicknesses any where from 2.0 to 3.5mm on a Selmer style guitar, though most are in the 2.2 to 2.8mm (spruce). Many are right around 2.5mm.

Stiffness and weight (or lack of it) of the top assembly are where the rubber meets the road (to mix metaphors) and the top thickness has been selected by the builder as what he/she thinks is appropriate.

Keep in mind there variances in body size, scale, bridge height, string weight, etc. from one guitar to the next that will affect choices made about the top. A Favino model, for instance, has a bigger body than an H. Selmer guitar.

There are a number of varieties of spruce, but even within species, wood can vary in stiffness quite a bit, so experienced builders think in terms of stiffness (and mass), not thickness. They are also blending the stiffness of the top with the bracing structure to obtain desired tonal characteristics.

Also keep in mind guitars are very complex and there is great deal that is not fully understood though there has been no lack of trying by people far brighter than I. The converse of this is that decisions about part thickness are not always made for good or ideal reasons, even if they might work well in that particular context.

If you are building from plans, however, then I'd just go with what they call for, assuming something like the Francois Charle or Michel Collins plan. Until you have built a few and start making your own design decisions, the variances won't make a huge difference overall. I'm still gigging with the first Selmer style guitar I built without plans seven years ago, it is far from ideal in many respects, but still quite adequate.

Bohemian

Thanks Craig.