Official Luthiers Forum!

So I just finished my first build around a week and a half ago and want to start on my next build but have a question about tops and longevity.
I am super pleased with the way my first guitar sounds, it's loud, and responsive and has a nice even tone across the strings so I would like to build the next one the same way. My question is, when can you be confident that your bracing will hold up to string tension for years and years? I obviously cant wait ten years to see. I've been putting a straight edge on the top and looking for deformation but it has stayed the same for the most part from day one. the top is red spruce .11 thick braced with red spruce and I used a pretty standard scalloped Martin x-brace about .55 or .6 at the intersection.

Any insight would be appreciated.

Thanks, Brandon

I suggest you get the Gore/Gilet books, as they will give you a lot of insight on how to answer that question. As a quick reference, 5 degrees of bridge roll is a metric. That is, measure the amount the bridge rolls with and without the strings on. If it's within 5 degrees you're probably good. But, as a new builder, the books are invaluable, worth way more than they cost.

You can't without waiting years and years. What you can do though is be conservative with what you do with your guitars in terms of selling them... until you find some way to glean some useful data. Some of my early ones were given away with the only thing that I asked for in return was data, how's it doing, any issues, etc. I also attempted to select recipients for my gifted guitars who would play them often as well.

One of the things that you have going for you is the use of time tested Martin type designs. It's not easy for any guitar manufacturer to remain in business, an understatement.... and very nearly all of the older companies have either perished or are these days simply a vintage sounding name that are built like model airplane kits in China using unserviceable glues.

But in the case of Martin the designs have stood the test of time and this permits us to have for lack of a better word... a parasitic relationship with tradition and those who came before us.

I have faith in the traditional designs and see them every day for better or worse and usually for the better. Mind you I am not dissing innovation but if your question is what will this stuff look like 100 years from now newer designs can't tell you any answers but traditional designs most certainly may.

Thanks for the quick replies guys! Ed, I drew up a 5 degree angle across the width of my bridge in my Cad/Cam system and it appears that it translates to about .14 of roll across the 1.7 or inches of the bass side of my bridge. The actual roll I see looks to only be about .02 when under string tension so it appears to be fine. Phew! Buying the Gore/Gilet books are on my list when I have some extra cash.

Hesh, I agree totally. That design seemed the safest for a newb to use having been around for so long. I wanted to build it lively and responsive being that my main use for this guitar would be fingerstyle and I heard lots of new builders over build their first, I was just worried i may have went the other way and under built it.

Hey Brandon. Give yourself some credit and pat yourself on the back it's highly likely that you built a very nice guitar!

Another benefit of traditional designs is that we know what to expect in terms of the possibilities because for better or worse we have all heard and played rather great guitars and not so great guitars.

In my experience with lightly built instruments since I went this route intentionally... you can also often hear a lightly built instrument in so much as much of what we hear is the wood. Use less wood perhaps hear less tone etc... Lots of Luthiers believe and often say so that lightly built instruments if you went past the point of no return can sound a bit thin. They are responsive and that's one of the goals but I would liken a lightly built acoustic guitar to some of the differences that can be heard between single coil and hum bucking pick-ups - there just seems to be more tone present when an instrument has not been built too lightly.

If you like what your hearing and by the way it will only improve with time and additional settling in, seasoning, use, exposure to good karma you did just fine!

By the way I have the utmost respect for your thinking in wondering enough to actually ask if there are any torture tests or quantitate scientific ways to predict the life span of an instrument. You have your eye on quality and that says a lot about you - all good!

Thanks for the encouragement Hesh. I've been a guitar player for over twenty years now and in manufacturing and engineering all of my adult life so I guess I take both of those mindsets into my guitar philosophy. I really believe in individual built handmade items of all sorts and want quality in everything I build whether it's a guitar or a chair or aerospace machining in my day job. Thanks for taking the time to reply.

I tip my hat to the "acoustic guitar innovators/experimenters" in the world, but I have to agree with Hesh the big guys have done the testing for us and also establish the longevity parameters with tens of thousands of samples in the field. These days it is a fairly simple matter to copy a good design with a very high likely hood the copy will sound close to what is expected. Some of the premier makers like John Grevens, Preston Thompson, Wayne Henderson and many others, have proved this to be a good path leading to very satisfied customers.

_________________
Ken Cierp

http://www.kennethmichaelguitars.com/

A great recommendation, BUT:

The number is 2 degrees. Yes, two! That is what the book says!

If you have one of those fancy phones with a level app it's easy to measure. Chock the guitar level on a bench, stick the phone to the bridge with poster putty, keep everything still and dump the string tension. See how much the bridge rotates.

Here's another approach (or two), different to what's in the book.

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

http://www.goreguitars.com.au

Oops, been a while since I read that part....

Haha, well luckily it's seems to be less than a degree so either way. When I saw that the rear of my bridge would have to lift .14 to get 5 degrees I thought that seemed like a whole lot! i would have freaked out if I saw half of that.