falcate bracing

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Max Dickinson
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falcate bracing

Post by Max Dickinson »

Falcate Bracing
There have been many bracing designs used over the course of Jay’s building career. When he started out with a kit, the bracing used was an x-bracing pattern A good learning experience. There were difficulties present. Shaping each brace to the curvature of the body was a tedious and repetitive task. Cutting them out to the right shape and height for strength and voicing was an imprecise process. A mechanical engineer, Jay searched for a better way. As more guitars were built there were improvements in design.
The current guitar bracing patterns that we use is called a falcate bracing pattern. This is our acoustic guitar soundboard bracing
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This is vastly different than a traditional x-bracing
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There are myriad reasons to use this bracing system. It is a design inspired by two Australian luthiers. The key is to use a curved bracing system instead of straight pieces. The curved pieces are bent into shape then placed onto top or back. There are six braces in the guitar back or top, three sets of two. They are placed symmetrically on the back in pairs. The direction they are lying is such that the longest part of them is in line with the tension the strings are providing. Running from the read to the bridge and up the sound hole. This provides the maximum amount of support over the axis that the tension is applied while keeping the amount of tension in the minor axis minimal. It is very flexible along that axis this makes it a more responsive top as it can vibrate more freely. There is less impedance to some of the modal resonances and provides a more clear and articulate tone.
Another innovation is the use of graphite in making the braces. The braces are made from three pieces. Two pieces of mahogany and a strip of carbon fiber. They are epoxied together and then sliced laterally. The grain of the wood is facing straight up, and the carbon fiber is along the same axis, this provides a significant amount of strength. These are hard to break. Even flexing them, not along the strong plane, is hard to do. They are significantly stronger now the pieces are alone. In addition, the surface area of the brace is minimal an acoustic guitar bracing dimension of 0.3” that’s making contact. Now, we have a strong brace that is providing the most amount of support under the bridge and sound hole.
The chances of this guitar undergoing bellying, where the area beneath the bridge swells. This effect occurs due to the tension over long times pulling it up. With the falcate bracing system there’s enough support to minimize this effect. This is one of the advantages of a Portland Guitar
Here are the pieces that are used to create a brace
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The braces as they are placed onto the back or top, smaller in the final form
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The next benefit of the acoustic guitar bracing patterns is a building advantage. Each of the curved braces is already part of a circular piece. Since the top and back want to be bowled surfaces at the end, the braces can be placed directly onto top or back and glued into place. There is no sanding of the bottom of the braces to conform to the curvature of the top. The braces are already conic sections that lie within the bowl. Once they are being glued on in the go-box the top or back is forced to take the round shape of the mold and hold it in shape. This reduces the amount of time spent on repeating sanding by a lot and frees up time to spend on detailing.
The last innovation with the braces is the process of tuning. There is a misconception in the luthier world that tap-tuning the top will account in better voicing and sound. Sanding away parts of the braces in special spots doesn’t have a large effect on the tone. The thickness of the top has more of an effect then small places here and there in the braces. The shaping of the braces tapered down to a point is a good practice. Our process is to simulate the tension from the strings and then sand the braces. The top is put in a jig with the sides supported to simulate a guitar body and top. The top has a lever arm with a weight hanging off it. This is how the torque is applied. We know that at one meter or so and at 2 inches of deflection with a 10-pound weight we can simulate the 200lbs of tension on the top. If the deflection is less than two inches than we know there is too much strength in the braces. The braces are sanded down at their modal points to bring the tension down. This ensures a minimally braced top and thus one that has the best tone. The act of sanding down the strength of the braces allows for greater flexibility and more vibrational response. This improves the tone and responsiveness of the guitar. We built this with a jumbo body and the feeling on the body was incredible.
Here is the top in our contraption:
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This is the lever arm attached to the top which simulates the tension. When the weight drops two inches, we know that the right amount of force is being applied to counteract the tension.
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Here’s what it looks like to sand the braces
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This build was for an acoustic bass guitar, so the braces are rather thick
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Here is the guitar back bracing
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In a comparison between our guitar and a Collings guitar we can see differences due to the acoustic guitar bracing. We can see a quantitative difference in these two-frequency response graph the Collings guitar does respond on some notes, but our guitar is responsive consistently on every note to a great amount. The dip that is seen is how much the body resonance interferes with the note that we hear. This is where the guitar becomes special in how it sounds. The amount of variance indicates that the guitar is moving quite a bit and that the air cavity is coupled very well to the top and thus responsiveness.

Collings Guitar
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Portland Guitar
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There are many different variables in this experiment, bracing being one of them. First the woods were different, which could have an effect. The Collings had rosewood with a spruce top, while the Portland Guitar had ebony with a redwood top Second, the Collings was a dreadnought while the Portland Guitar was an OM. Despite these differences there must be an explanation for the spike that we see across all these strings. Some of the responsiveness is inherent in the top that is used. The rest I’m willing to contribute to the bracing pattern. This phenomenon contributes much to how we interact and feel the guitar.

Check out more in a post on my blog: x-bracing guitar

Alan Carruth
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Re: falcate bracing

Post by Alan Carruth »

Well,now we know where your 'main air' and 'main top' resonances are....

The 'falcate' bracing should give larger vibrating areas for the lower 'signature' resonances, much like an archtop. I've only seen a few of these, and never made one myself, but it's interesting.

Steven Smith
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Re: falcate bracing

Post by Steven Smith »

As I understand it, falcate bracing is based on work by Trevor Gore and Girard Gilet as documented in their book Contemporary Acoustic Guitar Design and Build. Based on the info in the book I built a falcate dread in 2012, it came out quite nice. I think it is a good bracing system although I see you are using a different orientation on the carbon fiber then what was outlined in the book.

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Barry Daniels
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Re: falcate bracing

Post by Barry Daniels »

Max, I don't think you are giving sufficient credit to Trevor Gore. You are making some small deviations from the techniques shown in the books but they don't really seem to be improvements. And who the heck is Jay?
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Max Dickinson
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Re: falcate bracing

Post by Max Dickinson »

I'll introduce myself a little better. I'm the marketing person for my dad, Jay. His full name is Jay DIckinson and he builds under the name Portland Guitar. He's a mechanical engineer and been building for around 15 years. Even though I'm posting as myself most of what I share are my dads thoughts and based on what he shares with me. The techniques are largely shown in the books by Gore and Gilet, they've been very inspirational for him.

Clay Schaeffer
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Re: falcate bracing

Post by Clay Schaeffer »

When we speak of "X" bracing we don't give credit to C.F.Martin or his predecessors who developed it. Likewise we don't credit Torres and his predecessors who developed fan bracing when we say we are using it. I think saying "Falcate bracing" sufficiently identifies the source of inspiration and gives credit to the developers of that system.
Back when Mario Proulx was talking about laminated braces I had thought about using two curved laminated braces in place of the typical X. I discarded the idea as being more trouble than it was worth. That Trevor has developed a complete system around a similar idea - Kudos to him.
There have been a number of successful systems for bracing musical instruments, so we picks our poison and takes our chances. :lol:

Bob Orr
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Re: falcate bracing

Post by Bob Orr »

Biggest issue I have is, I don't fancy ever having to replace the bridge plate on one of these!

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Barry Daniels
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Re: falcate bracing

Post by Barry Daniels »

Clay, I was bothered by the tone of the post. They only said is was "inspired" by two Australian Luthiers and then went own to talk about "their" methods and their guitar. It felt like a marketing blitz. Maybe I am off base here, but it did not appear like the "normal" post we see on this forum where people are mostly sharing their original ideas and asking for input from others.
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Clay Schaeffer
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Re: falcate bracing

Post by Clay Schaeffer »

https://www.youtube.com/watch?v=3HB8MDl ... mb_rel_end
https://www.youtube.com/watch?v=kYBzedx ... e=emb_logo
The guitars have a nice mid-rangy blues box kind of sound.

Yeah Barry,
It is a bit promotional. He did say he was the marketing person for his Dad. I think he is being transparent about who he is and what he is doing - promoting his father's work. He was "selling" for his father, not the two Australians. A Son proud of his Father - best kind. Much of it was verbatim from his blog. I just took it for what it was and wasn't offended by it, and I did learn a little more about Falcate bracing.
We could all use a little more promotion. A few years back one of my sons set up a website to promote my instrument making. It was nice of him to do it, but not something I asked for. I never did anything with it, so it died on the web.
We don't do much self promotion here. Occasionally we will show something we have been doing if we think others might be interested, or discuss ideas we may have heard or thought about. It is nice to see what others have made or are working on, and reacquaint ourselves with old friends and see that they are still on the right side of the grass. Some might see it as self promotion, while others just see it as sharing.
But I do agree with you, Barry, it is a bit promotional.

Max Dickinson
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Re: falcate bracing

Post by Max Dickinson »

Hello Everyone,

Thank you for the feedback. I'm definitely toeing the line between informational and promotional. It's a line that I'm learning to walk as I make content for my website. I'll try to better differentiate between which is which and post here accordingly.

Clay Schaeffer
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Re: falcate bracing

Post by Clay Schaeffer »

No big deal Max,
One person's promotional is another person's informational. I learned something from your post - how you determine what you feel is the optimum bridge rotation.
And welcome to the forum Max. Hope you continue to post here.We are generally a pretty friendly bunch, although at times we may appear to be a bit curmudgeonly.

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Barry Daniels
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Re: falcate bracing

Post by Barry Daniels »

I guess that makes me the curmudgeon. Probably not too far off the mark.
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Clay Schaeffer
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Re: falcate bracing

Post by Clay Schaeffer »

Actually I was speaking of me, Barry. My friend calls me the Hermit in the Hollow, because of my somewhat antisocial nature. I spent most of my "growing up" years alone in the woods, and the fields, and the marshes. I never made many social contacts, and still today, I am quite happy to "social distance" from 99.9999994 percent of the people.

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Barry Daniels
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Re: falcate bracing

Post by Barry Daniels »

I think being a luthier and being a hermit are somewhat synonymous. I bet ol' Antonio was a real grumpus.
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Alan Carruth
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Re: falcate bracing

Post by Alan Carruth »

"I bet ol' Antonio was a real grumpus."

Assuming you mean Tony Strad; by all accounts he was a workaholic who never took his shop apron off.

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Barry Daniels
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Re: falcate bracing

Post by Barry Daniels »

Edit: Sorry
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Matthew Lau
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Re: falcate bracing

Post by Matthew Lau »

I think he meant Antonio Torres.


Thanks for sharing this. If there's another shutdown, I might try doing that on a bass.

Alan Carruth
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Re: falcate bracing

Post by Alan Carruth »

Barry Daniels wrote:
"I have been here for over 20 years and have been trying really hard to be helpful all this time (especially to newbies). I feel like I have paid my dues, so to speak."

I've been here about as long. Back when, iirc, you were not even allowed to mention a commercial web site, even if it wasn't yours. That became insupportable after a while, but it did help set the tone around here. There were also more stringent restrictions on picture size, which I welcomed back when I was on dial-up. You can't blame a newbie for not knowing about that, of course. OTOH, I did find that big picture dump to be unwelcome, even with a USB connection.

This is the first forum I signed up for, and the first web site I check out every day. As Barry says, it's always been pretty focused on being helpful, and I appreciate that, and contribute when I can. I've seen a couple of more 'competitive' sites come and go.

Max Dickinson
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Re: falcate bracing

Post by Max Dickinson »

Thank you everyone for the feedback. I think this is a great forum with lots of good information. It's helping me to become more knowledgeable. I think I understand the atmosphere better and will hold off on making promotional posts. I'll keep the pictures to a minimum and make them compressed when I use them, I didn't know that many pictures could be a bad thing. Thank you all

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Karl Wicklund
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Re: falcate bracing

Post by Karl Wicklund »

Thanks Max. Glad to have you (and everyone else) here!
Kaptain Karl

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