I'm measuring intonation for the nut and saddle on a Finnish Olav Löf guitar from 2003. Olav made this one with rowan wood in the bottom and sides, maybe the neck too. The bracing of the top is somewhere in between a ladder and an X-bracing. Still in good shape, even if the top had a bit of a hump behind the bridge, the reason for the intonation work.

Consider doing your intonation setting with the instrument in the playing position in your lap or if you have one in a neck jig (which is not necessary). You will see on many guitars that the intonation can change several cents or so from on it's back to in the playing position.

I set-up around 600 guitars a year and these are very comprehensive set-ups that people pay premium prices for and the expectation is as close to perfection as possible. The difference in what I read intonation wise and I use Peterson strobe tuners too is noticeable and even audible in some examples when you set the intonation in the playing position.

I'll add for others since I know you know this Roger setting the intonation is important but it's as important to have the nut slots cut low and correctly or your intonation settings will be pulled off and the instrument will be harder to play.

Yes, there is a difference in the shape of the neck to the guitar when laid on it's back compared with the same guitar in playing position. In my Stewmac Erlewine jig, I have seen on the measuring clocks that the nut will travel down 0.1-0.3 mm laying on it's back compared to playing position, with a light neck and no truss rod (only a carbon rod). An electric guitar or electric bass with a heavy truss rod will deform even more.

That checks out with math I did a quick calculation approximating the neck as a cantilevered rectangular beam 40x18mm, 40cm length, 10GPa Young's modulus, with 400 grams uniformly distributed, and got 0.1mm deflection.

Yes, there is a difference in the shape of the neck to the guitar when laid on it's back compared with the same guitar in playing position. In my Stewmac Erlewine jig, I have seen on the measuring clocks that the nut will travel down 0.1-0.3 mm laying on it's back compared to playing position, with a light neck and no truss rod (only a carbon rod). An electric guitar or electric bass with a heavy truss rod will deform even more.

I do all my intonation measuring adjustments, not shown in the slides, with the guitar in playing position in my lap. In the Erlewine jig with strings at tension before doing the intonation work, I also set the measuring clocks in playing position before sanding the fretboard and crowning the frets with the guitar on its back.

That checks out with math I did a quick calculation approximating the neck as a cantilevered rectangular beam 40x18mm, 40cm length, 10GPa Young's modulus, with 400 grams uniformly distributed, and got 0.1mm deflection.

And if the neck is resting on a sort of full length neck rest it presumably will be less?

.... measuring clocks....

You mean dial indicators, Roger?

Now that is interesting Jim. Cool shape that I've never seen. All fits together. But I don't understand the edge on the top. Is it thick, and then routed down .06" or so over the playing surface? Maybe a band for some kind of inlay? I have no idea what's going on.there!

I see that it isn't done, but you got.me confused. Maybe that's.not.too hard to do?

I left it thicker around the glue area and router'd down to correct top thickness its simply for visual effect. No real mystery im hiding lol. The entire guitar is an experiment in trying different ideas. Just for fun.