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I am very close to finishing the top, back and rims for this guitar. My current plan is to press non radiused falcate braces in either a 25' or 30' dish, Glue the transverse brace down flat. Also the top rims are profiled dead flat. My past three classical guitars have been built Spanish style with a flat solera with a dished lower bout. So I have always profiled the top rims flat. I am going to have a bolt on bolt off neck and use a wedge under the fret board to set the angle. At this point I intend to leave the top rims without a radius, but I still am at a point where I can still profile them and am open to suggestions.

Here is what I have so far.

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http://www.Harvestmoonguitars.com

Is there no information in Trevor/Gilet books?

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Steve Smith
"Music is what feelings sound like"

There is information, The book uses a radius dish on the top then flattens the upper bout. I guess it is not quite adding up for me, to the point that I trust my understanding. On a classical I ultimately want the top of the fret board to have a forward angle relative to the top. If I radius the top even after flattening the upper bout as suggested in the book I will have a angle toward the back of the guitar like a steel string. In the build book he achieves the forward angle using a 4mm or so wedge between the fret board and the neck.The 4 mm is on the nut side. My experience would have had me using a 2 mm wedge so I could suppose that the additional couple millimeters were used to account for a backwards angle of the neck relative to the top. Going off on my own I thought to leave out the radius on the top rims have the neck and the top at 90 degrees to the rim and to use the appropriate size wedge between the neck and the fret board to achieve the desired string height at the saddle.

I am still at the point where I could put a radius of 30' on the top rims. I will glue the braces to the top as suggested in the book, flat transverse and the rest of the braces glued in the 30' radius dish. At that point I could see how that braced top would fit on the flat rims I have and decide then.

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http://www.Harvestmoonguitars.com

I went ahead and sanded a radius on my top's falcate braces just like I normally do, rather than pressing in flat ones. Probably doesn't make a big difference.

I left mine flat, On falcate builds , but now that I bought the brace sander (LMI) it will be a 25 ft radius. The bottoms of my braces never came out flat on the radius dish.

I don't understand why the falcate bracing would have any bearing on neck angle. Seems to me you should be able to just do your regular thing. The geometry should remain constant. ?

Yes that was my thought as well and that is where I am heading. I do trust that I will get the correct geometry or I can just play with the wedge under the fret board until I do. Mainly my concern is that I know that I am deviating from the build process and the design in the Contemporary Acoustic Guitar Build book. Also there are some differences; the CF falcate braces go up to the upper transverse brace (the only one) where the fan braces stop before the lower transverse brace. So when I glue the top flat I am flattening out a longer longitudinal curve that the falcate braces are trying to hold. My thought is that it is not a big deal and the curve the braces are trying to hold will just result in a slight dome. That is my hope anyway.

Thanks guys for all of the feedback

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http://www.Harvestmoonguitars.com

No CF on the braces? Deviant indeed!

Let us know how it works out...

It may not be glued down yet

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Steve Smith
"Music is what feelings sound like"

I will have CF under and over all of the braces. I started the glue up late this morning.

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http://www.Harvestmoonguitars.com

Aha.

For those interested, you can find my response here.

The Book doesn't cover falcate braced classicals in any detail (I thought falcate SS, X-braced SS, fan braced CL and lattice CL was enough!), so largely you're all on your own with falcate classicals. All the methodologies still work, though. That was much of the point of the books: how you realise the ideas that you guys come up with.

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

After reading Trevor's response I am going to put a 32' radius on the top rims and then flatten the upper bout probably using a plane. I had not completed the final profile on the rims. My rims are currently about 2 mm too tall, as I wanted the room to put a radius on the top.

I will do the final profile after I get the radius dish back from my final layup with it.

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http://www.Harvestmoonguitars.com

I made a bunch of progress on this guitar. I did radius the top rims, but flattened out the upper bout a bit.

The top as a 32' radius, the back has a 10' radius. Although the guitar looks more contemporary all of the final set up will be within the classical guitar range. I put a 20" radius on the fret board.

It is starting to look like a guitar, maybe even a bit more like a classical guitar. I still need to finish carving the neck. Although it is a more contemporary design it still is a classical guitar size and the set up will be within the classical guitar range, for neck thickness, nut width, string spacing and what not.

I am thinking a bit about the final details like adding the closing binding between the neck and the rim and the cutaway. It would provide a clean finish, but it is a bit of a busier look than I really want.



All and all it is starting to look like a guitar.

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http://www.Harvestmoonguitars.com

It is coming along very nicely indeed!
I have been watching this build closely - very innovative.

Cheers!

Rob

Very nice!

Thank you Rob and James,

I did a bunch of prep work and cut ramps in the head stock slots. I made squared off ones for the first time. A little scary I just cut the edges with a razor saw and carved out the waste with a chisel. There is a bit of back and forth to get the line between the veneer and mahogany to look symmetrical.

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http://www.Harvestmoonguitars.com

I prefer the look of the square ramps, and it ensures clearance.
Good choice!

Thanks Robbie,

I am getting really close on this one. I just glued on the bridge and I thought I would try a tap test. I think it came out with working values. Depending what happens with the strings, I can add mass to the sides if I want to lower the top off F# (I know it is right on F# as I have my falcate SS guitar on the wall with the g string tuned down to F# and it started singing. I left the bottom back brace pretty tall so I can get the back on target as well. I will wait for the strings first. From a closed box tap test the top came down two hertz with the bridge and air up about 2 Hz. My fret board covers a bit of the sound hole so that might be what changed the air resonance.





On to the fretting the guitar and finishing the compensated nut

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http://www.Harvestmoonguitars.com

It's looking good. I bet the box sounds great when it's thumped. The falcate bracing makes a big difference.

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Steve Smith
"Music is what feelings sound like"

I completed my first falcate classical. All and all the project came out OK and the guitar sounds good, but I did miss my target frequency on the top. As seen in the figure below I was low around 178 Hz instead of 190 Hz for the top. This lower frequency puts the top and the Air resonance an octave apart 88.6 Hz. I am not really hearing any horrible weakness around F but I am also not hearing what the guitar could have sounded like. I did put the back about 4 semitones away at 224 Hz. Ultimately I should have had the falcate braces taller. Possible the 7 mm that I used for my SS.

As part of a postmortem on the project I looked back at my design assumptions. I noted that my falcate SS top was 172 Hz not the 180 I used in the assumptions for my relative analysts. If I was a bit more careful early on and knowing that I wanted to push the target top resonance 20 Hz higher than my SS I may have left the braces taller.

Over all I am still happy with what I have and I have good data for my next attempt and a good guitar. I learned on lot with this guitar including the bolt on bolt off neck design for a classical guitar that I will incorporate into future guitar projects.

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http://www.Harvestmoonguitars.com

Excellent looking instrument !!! Sure looks like a keeper the me

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Joe Beaver
Maker of Sawdust

You mean 224 for the back?

How does it sound? Generally the hard part for classical is good trebles. The hz numbers are a good guideline, not law. Is the bass wooly and overbearing or is it clear? More than one set of numbers works...

That is 224 Hz

Actually the guitar sounds pretty good. The bass is very clear and the trebles sound good able to hold their own while playing. If anything I been worry the G string, but each day it have become more full bodied and now plays with real presence.

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http://www.Harvestmoonguitars.com

Really nice John - very well done!!!

Looks like you fretted the guitar with the board on the neck and the neck on the guitar and if this is the case that's nice to see too.

Lots of folks tie classical strings differently and there are lots of ways to do it well too. Might be a good thread sometime to discuss different methods for tying classical strings. I think that part of the cause of my hernia was stretching classical strings for about an hour..... Suckers just keep on stretching.

Great guitar Job!