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I've been reading both Gore and Somogyi on bridge design and one says go as light as you can while the other says '35 grams, no more no less'

The search function gives many different opinions of course. So for a scalloped jumbo fingerstyle steel-string built lightly, what would you choose and why? On previous guitars, bridges were mostly 35 grams ebony. For this one, I have a Brazilian blank page that just rings like metal!

Our bridge design will be pinless with a surface area of 46,5 square cms

I would and have made BRW bridges; I like the look and sound. A bridge needs to be considered one brace in a system of braces on the top. The concept that there is a generic magic number for a bridge weight sounds strange to me. The mass of a bridge affects both the top resonance and the efficiency of the top. Heavier bridge means it takes more energy to move the top.

Gore falcate design relies on the bridge to provide the cross grain stiffness as the top is not braced down the center of the guitar. The book suggests going light and use CF to provide addition stiffness.

I am sure that Somogyi has his own system of top thickness\stiffness and brace stiffness, and in his system I could believe that 35 grams is just right.

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http://www.Harvestmoonguitars.com

I have made a 28 gram BRW bridge for one guitar. I think that was too light for my taste. I added heaver bridge pins to bring up the weight. I now am aiming for 32 grams for my bridges. Those where on Martin type OMs.

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EddieLee

Maybe Smgy makes all 35g bridges as a control?

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Pat

Who uses carbon fiber in their bridges and why?

The first time I saw it was Gore. A layer sandwiched with epoxy in the bridge thickness will make a bridge resist splitting. Clever.

Following Gore\Gilet book I have done 6 that way to go on falcate braced guitars. As mentioned above one can use lighter (less dense) wood with the CF increasing the stiffness. I used walnut for a couple of guitar bridges and ended up with a light stiff bridge.

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http://www.Harvestmoonguitars.com

Gore's falcate tops are a world different from a scalloped X brace.

The function of the bridge is to tell the string where it ends, so it will 'know' how long it is and what note to make. In theory it's supposed to be 'fixed': not move at all. An acoustic guitar with a fixed bridge would not make nay sound, since the top would not be moving, so you can't have a 'perfect' string termination on an acoustic. This is one of the causes of 'wolf' notes. Your task as a guitar designer is to come up with a bridge-and-top system that produces the most sound you can without problems like wolf notes. You do that by making the bridge stiff enough and heavy enough to produce a decent termination to the string at all played frequencies. The variables in your tool kit are stiffness and mass, for the most part.

Stiffness primarily comes from the bracing, although the top is part of that equation in most designs (lattice braced tops being the major exception). Always keep the 'cube rule' in mind: the stiffness of a brace is proportional to the width and cube of it's height. Even fairly small differences in brace height can have large effects on the local stiffness.

Gore's falcate tops use braces that are tallest at the bridge, tapering out from there, and reinforced with CF. They're really stiff, particularly at the bridge. This allows him to make the top itself very thin and light, and also to use a light bridge, and still produce a decent string termination. He also relies on 'tuning' the systm such that the main low-order resonances that cause the biggest 'wolf' issues are placed at pitches between played notes.

Scalloped braced tops have the braces lower at the bridge than they are at the X crossing or lower down in the bout. Remember; if they're half as tall at the bridge they're only 1/8 as stiff. Since the top is not as stiff at the bridge location a heavier bridge is needed to 'fix' it enough to produce a decent string termination, particularly near the low 'main air' pitch. The tops are generally a spruce that tends to be on the dense side, such as Sitka or Red, and may be chosen to be on the dense side for the species. The added mass of such a top helps as well, particularly in conferring some 'headroom'.

In the end, every guitar design is a system, and works best if you stay within the parameters all the way around. If you try to mix and match from different systems you tend to end up with a camel at best, or something that doesn't work at all at the worst.