Thanks for your comment.

I think that the tools are definitely available to analyze how a guitar sounds after it’s built. However, there are many variables: what kind of wood is it made of?; how well is it constructed?; what is the shape of the braces?;etc… well, you get the idea. So, even thuogh there are rules of thumb on brace shapes and placement, so many variables affect the actual sound of a finished guitar it really is a process of refinement of technique to get something that sounds good and is reproducible.

With a trained ear, you can actually test the sound board before the guitar is completely assembled. It’s a process called tap-testing. Again if you have trained your ear, you can tap on the soundboard and if held correctly you wil hear a distinct ring from it. Varying the braces, etc. will change that ring and ultimately how the guitar will sound.

–Mark

I’m not exactly sure of what you mean when you say radiusing the x-braces.

Since this was a kit, my brace material already had a radius or crown along to top edges. SO, I did nothing there except to sand them until smooth enough for my liking. If I was starting with square stock and wanting to do this I would probably just use a block plane to do multiple small chamfers until I approached a radius and then sand it until smooth.

If you are referring to tapering the ends of the x-braces down to the sound board plate, then yes I did do that. This was done with a bench chisel with the bevel down so that I could work this into a smooth curve. Just take a little at a time and when very close to the desired taper then just dress with a little sandpaper.

–Mark

Did you end up radiusing one or both ends of the large x-brace? The handbook I’m following suggested radiusing the two lower bout fan braces and as well as both ends of the x-brace peices. If so what did you radius them to and what method did you use to get a good consistent arc? Thanks!

Tim

Sorry for the previous link – just look at my response to Kevin above for comments on a lefty setup.

–Mark

Thanks for your question. Take a look at the previous comments and responses. Look at http://thecraftsmanspath.com/2.....g-the-top/ for a prevuious response on bracing for a lefty.

–Mark

I’m not familiar with a Monterey or with repairing something like this first-hand.

I know that an old bridge plate can be removed but it takes some heat and humidity (depending on the original glue used) and you have to do it blind by prying it off with from through the sound hole (if that’s even possible on a Monterey).

Using another piece over the existing one presents at least two possible issues. One is that the existing bridge pins will probably be too short to work. Second, the added mass and stiffness of the additional piece would certainly change the tone of the guitar.

One method I’ve seen done is to remove the bridge and then drill out and plug the holes from above with new wood. Then the bridge is replaced and the new holes are drilled and reamed from above through the bridge. This takes a lot of care and accuracy to remove the bridge and re-install it at precisely the correct location for proper intonation and string action.

If you are not real familiar with this operation then it is probably a job for a competent guitar repair technician.

–Mark

I dont know what wood is used on a Monterey for the support, probably pine! LOL!. As I wont be able to remove the original damaged bridge support, would there be any issues with gluing a rosewood support over the original support?

What is your opinion of fitting a JLD Bridge Doctor?

Gavin

Typically the bridge plate is made from a hard wood (usually Maple or Rosewood) and is about .100″ +/- thick.

The plate is glued on with its grain running across the guitar or perpendicular to the strings. A plate that thin cut with grain running the other way would have the tendency to split along the grain (possibly even before it’s installed). The bridge plat often also has its corners tucked under the X-braces for strength.

–Mark

What is the best wood to use for the bridge support as this is a key component in preventing the top from lifting?

All bridge supports I have seen have the grain running purpendicular to the strings. What would be the effect of having the grain running parallel with the stings for strength?

Gavin

Thanks for visiting the blog.

While I am no expert on the subject, I can give you some thougths with regard to bracing materials.

The critical things in bracing the guitar are the stiffness-to-mass ratio and the elasticity of the wood. This is a fancy way of saying how strong is the material without being too heavy and how well will allow the strings vibrate the top and back to radiate sound from the guitar. This will affect both how well the guitar is braced for strength as well as how it will sound.

Having said that, Spruce is common on spruce topped guitars. It is relatively light while being strong. Cedar is also often used as a bracing material – especially on classical guitars that may or may not have a Cedar top. As far as Oak and Maple go, they would certainly be strong enough however, they would also be heavy. I have only seen Maple bracing on a Maple topped guitar. That’s not to say you couldn’t try it though. Many of the techniques that we study today derived from experimentation of luthiers long ago. They certainly did not know what would happen when they tried various bracing materials and patterns. What we see today is the results of them trying many things. If you’re willing to experiment a little, your efforts to try other things might yield something great!

–Mark

Guitar builder wannabe
Jimmy

Thanks for you comments an clarification on the left-handed bracing. Given its asymmetrical nature, it makes sense that it would be reversed on a lefty.

–Mark

Some of the pros have theoried that it is more important that the guitar bracing in the lower bout be assymetrical than oriented for a right or left hander.

Great job on the guitar!

Thanks for visiting the blog.

That’s an interesting question that I had not really considered before (I’ve never built a left-handed guitar).

Thinking about it, because there is a bit of asymmetry in the bracing design of this guitar, I would believe that the correct thing to do is to reverse the bracing. Most likely it would affect the bass and treble response of the top based on the locations of the strings on the bridge vs. the bracing pattern if it were built as is for a left handed version with the current bracing.

–Mark

A quick question… Generally speaking, is the bracing on the inside of an acoustic guitar the same on left-handed models – or is the bracing reversed?

Many thanks,
Kevin

The reason for the use of arching or a radius in the top and back of the guitar is the same as it is in architecture and engineering, to strengthen spans. An arched-braced structure is stronger than a similar flat braced structure. So, the arches help to stiffen the guitar top (and/or back). An increase in stiffness will improve the high-frequency response of the top, making the guitar brighter. It will also allow the top (and/or braces) to be thinned further, reducing its mass and increasing the volume (loudness) of the guitar. The increased stiffness will also help to reduce the effects of humidity on the top (humidity will tend to bow the top out during periods of high humidity and dish the top in when the humidity is low ).

As far as flat-top guitars, there are some that are made that way. I’m not sure what kind of “sound quality penalty” there may be. However, from the reasoning above (all other things being equal), it is probably reasonable to believe that they are less stiff and have thicker tops and as a result are not as crisp sounding or as loud as an arched-top guitar. Of course, other things may be designed into a flat-top guitar to achieve similar sound attributes to an arched-top.

There is a real art to shaping and trimming the braces on a guitar to alter its eventual sound qualities. The process is something that looks to take many years of practice and experimentation to acquire – certainly not something I have on my first guitar!

–Mark

Another great installment! Not only am I learning the clamping technique using go-bars, but also learning the the WHYs of the bracing.

1) Can you please elaborate on the reason for having a radius on the top of the guitar?

2) Do you incur a sound quality “penalty” if the guitar top does not have a radius?

I appreciate all the detail and the care it takes make this instrument!