To tuck or not? L-00

[buffalohunt]

I'm building twin L-00s. The sides are bent and lined, the top and back are both braced. As I am voicing them I am considering what to do with the ends of the X-braces. Traditionally, Gibson did not tuck these braces on the L-00 (and other flat tops), but just about every modern guitar is tucked under the kerfing now.

I've read some advantages of not tucking them is that it loosens up the top to resonate more, and make up for some of the sound loss on a small body acoustic.

I'm wondering if the reduction in strength is worth the improvement in sound.

If I did tuck my braces, could I achieve the same gains by thinning the top around the perimeter? If I decide not to tuck, I will taper the ends down to 0", like the tone bars.

Thoughts?

[jaywalker]

Tuck one and not the other, see what happens.

[Bruce Sexauer]

Bracing is essential to top resonance, w/o adequate braces and with state of the art thin plates there is potential for floppy ineffective surface. Thinning plate edges increases this risk, and flies in the face of how I believe guitars actually function.

[redir]

I know that some steel string builders thin the edges but it seems more practice among classical builders. I believe in Gore's book on building steel strings he does thin it but it's all part of his building style too.

I now almost always leave the lower bout X-Braces thinned to zero and the upper are tucked in. Actually I do what Gibson used to do which is thin the brace out so that it's paper thin and then glue the linings right over it. Gibson didn't make them thin enough on many guitars and it causes a stress riser there so if you choose to do that then make sure it is like tracing paper thin, very thin.

The other option is to thin to zero before the linings but since braces tend to fail by peeling away, like removing tape, it makes sense to me to prevent that.

One model guitar I make I still tuck the lower X-Brace in because the first one I built I did that and it sounded fantastic so I want to emulate that one for every one of them.

[Alan Carruth]

Tucking (inletting) the brace ends is done to keep them from coming unglued over time. Most glues are not very resistant to peeling, so if an end gets loose, say, because somebody banged into the top at that point, it can just keep peeling up.

The torque of the bridge produces a down force on all of the braces between the bridge to the neck, and the neck itself exerts significant torque at the upper end. The upper transverse brace has to withstand a hefty down load. The ends of the UTB, and the upper ends of the X braces, need to have some height, and to be supported so that they can't start to peel. Classical makers, building from the top down, often use brackets glued to the side to support the brace ends. On steel strings it's more common to inlet the braces into the liner, although some of us do use brackets at times as well.

The braces that end below the bridge are less likely to peel up because the static bridge torque is not pushing them down. They can still come loose if someone leans on or knocks into the top, though. If you choose not to inlet those make sure they are shaved down in height enough to be able to flex with the top and avoid a stress riser. I usually inlet the lower ends of the X braces as well, even though they're not very tall: I don't feel comfortable taking them down to nothing, although some folks do.