Relationship of neck, bridgeplate and tailblock

[fidel1ty]

For you builders out there...

Has anyone tried carbon fiber hooks, connecting the neck to the bridgeplate and then plate to tailblock. These "hooks" would tolerate stress, like a bridge under weight and relieve soundboard tension. I was thinking a carbon fiber bridge plate and possibly carbon fiber at the base of the neck and top of tailblock.

We can think of these 3 entities as the heart of the guitar, or like a frame of a car, and could build the body around it with much less tension that causes bridge lift, belly bulge, dumpling etc.

I suspect carbon fiber may be a good option for this because if its rigidity and ability to tolerate the stress of string tension, as opposed to conveying that stress to a thin soundboard.

180 lbs of pressure from string tension on a soundboard, year after year, sounds like an awful lot.

Just a wild thought.

[charles Tauber]

We could easily build a very rigid box that would withstand centuries of string pull. The problem is that it wouldn’t sound like much, since we’ve prevented it from moving (I.e vibrating). The issue isn’t one of how to build a strong enough body, the issue is how to do that while still allowing it to vibrate well.

Restricting motion of the bridge plate/bridge/top while still allowing it to vibrate well is what luthiers have been trying to do for a long time. The traditional X brace is one approach. Gibson’s double X was another. Lattice bracing another. Ladder bracing, tail pieces another. More recently carbon fiber rods from waist to neck block, reinforcement from end block to heel block, double sides, heavy interior “piano-like frame”, carbon fiber laminate braces... there’s the Bridge Doctor ...

[MC5C]

Many people do such things to their guitars. Rick Turner has used carbon fiber rods as buttresses from the neck block to hard points at the waist of the body. Others extend the strings to the tail-block so the bridge is not terminating the tension. I've used a longitundal brace just under the top plate between the neck and tail blocks to take up some of the tension of the strings on my X-braced archtops. It seems to me that the top bracing on a flat-top guitar is largely designed to take up and distribute those string loads, and taking them away might require, or allow, significant changes to the way a top is braced - or not!

[Alan Carruth]

What Charles says. It's pretty easy to make a guitar that is totally stable, where the bridge virtually doesn't move at all. They sell something pretty close to that under the brand name of 'Les Paul'. It's not noted for wonderful acoustic tone and projection.

[Arthur Blake]

Originally Posted by fidel1ty

180 lbs of pressure from string tension on a soundboard, year after year, sounds like an awful lot.

I'm not a guitar builder, but I think 180 lbs. on the face of a sound board would instantly shatter the wood.

The force is applied through a very short and very precise lever - the saddle.

That tension is held by the bridge, but that force is nearly in line with the plane of the sound board, and with bracing, it does hold the tension, year after year, with little deformation.

Just my $.02.

[bostosh]

Check the google patents for soundboard designs
There are many ideas, many thoughts on this problem.