Friday, March 28, 2014

Back in the Guitar Game: A Cross at the Heart of It

Take a look at this:
We're back in the shop after a little vacation from buildmyguitar.blogspot.com and Bruce Roper, luthier at Old Town School and guy at the heart of Sons of the Never Wrong (there is actually only one guy and two women, so it's okay and you don't need to send emails about sexism) is getting ready to brace the top of my guitar. This is one of the most important things in the construction of a guitar so Bruce is paying close attention to every aspect of it. He is getting ready to cut one of two braces that will form an "x" just beneath the hole on the guitar front. You don't get to see it, but if it's not done properly, the tone will be bad, the top will be weak and the whole thing might just blow up in your face once the strings are tightened to key.

We had a guest on this morning. Stuart Flack, a jazz guitar player and long time friend, came along to watch Bruce in action. The minute Bruce heard what Flack was about, he went into his house and brought out an arched top jazz guitar he had built so Stuart could sit and play while Bruce was working and I was watching. Here's a contented Stuart and Bruce's fine guitar, which isn't made out of anything very special but sounds and looks very, very good.



Looking at this again, I'm thinking you would all be very happy to hear Stuart play, too, but I'm not facile enough to get all that stuff working at once. Stills I can do, but stills and a sound track and even one other little thing and my head will explode. So enjoy the picture. Enjoy it as much as we enjoyed having Stuart in the studios. Lots of big, full jazzy chords and little leads and progressions, all of them very smooth, very much on target. Someone into jazz should buy this guitar, which has a great heart and voice. But whoops! I digress.

This round disc Bruce is working on is actually a round slice from a 25' radius imaginary ball. It provides exactly the right curve for the top of this guitar, but not without some work, and that is what Bruce is setting up just now. Note the sheets of fine sand paper on the disc. That stuff follows the curve of the disc, too, so anything you rub on it long enough is going to come out with that 25' radius curve to it. That is important because Bruce is going to take that part of the brace, glue it up and set it on the inside of the top of the guitar, so it has this very smooth, natural curve to it. But to do that, he has to cut the "x" braces just right, so they cross in the proper place and make a perfect little platform on each side of the guitar bridge, which will be glued on later.
He is doing some careful placement here with each of the braces to make certain they start and stop just where he needs them to start and stop. There's some guitar building philosophy that comes in at this point. Some luthiers say that "x" needs to be close to the sound hole if the guitar is to be bright, and a little bit back if it is to be bassy and deep. Bruce says he doesn't know if any of that is true. What he cares about is that the cross of the "x" is di-sected by the seam going down the center of the top of the guitar. Symmetry is what this is about. That you achieve by placing it very carefully. Then you use a pencil to draw lines of the sides of the braces where they cross, so you will know where to cut the indentations that will allow them to be pushed together. Once you have that measure completed, it's time to cut.

Bruce is using a small Japanese pull saw to cut into the braces, which he has lined up beside one another in a little clamp on his workbench. You do it that way because it guarantees that the cuts are going to be the same size, which is just short of the drawn lines on the spruce braces. If Bruce cuts on the outside of the line, the joint will be loose and not worth much when all that pressure hits the guitar top. Just inside gives him a chance to use a fine file to cut away what remains so he can prepare a very tight joint. Cut, size, try it and cut again. Then he moves down to a set of files used to take off any remaining wood. This is how you cut a joint that is going to be tight.
Bruce still needs to take off some wood from the bottom center of both sides of the joint. The objective is to have them fit together and create a flat surface, which is going to be glued to the inside top of the guitar. After not many tries at all, Bruce gets it completely right. The pieces fit and are ready to be glued.
Bruce wants to insure a solid bond with the curved surface of the guitar, so he spread his glue with his finger. Much later, he will sculpt the glued on braces to give the top great resonance, which is important in guitar building. For now, he just wants to make certain that every little part of that brace has enough glue to build a strong bond with the top of the guitar. He's satisfied. Now its time to glue up the braces and give the top a little curve.
He is using fiberglass garden stakes to hold the parts down. One part goes against the plate at the top of Bruce's workbench. The other part sits on the brace. He will have about a dozen of these sticks in place when he is done with this part of the job. Each will apply exactly enough pressure to guarantee the wood is glued, but not enough pressure to wreck the top of the guitar. It's an old fashioned way of placing the braces, to be sure, but as certain as can be. The factories that make guitars use vacuum devices to apply uniform pressure to the glued brace.


Now that he is just about done with the stakes, you can see how the "x" sits on the inside of the top of the guitar just south of the hole. there will be perhaps three other braces on the inside of the top before Bruce is ready to sculpt the braces. One will cut across the bottom on an angle, another across the top will hold the surface flat so the guitar neck fits properly. A couple of other ones sit in random places that need reenforcement. When its done, it will include a place just below the "x" that will sit beneath the guitar bridge and be tied into the whole structure. That's why the placing of the "x" is important. The bridge is glued to the top side, but it sits directly above the legs of the "x", which makes it very strong once its all glued together.

Everyone was under some time constraints on this particular morning so we just stopped with the "x" brace once it was placed and glued down. We had a little conversation after that about what we want to do with the headstock on the guitar. That's a pretty distinctive place for decoration, and neither of us is interested in getting too fancy with it. But Bruce has come up with a very nice touch that will make this headstock unique.

Here is how it looks on paper. Bruce says the various parts of the top cut form the initials "CM" for Charles Madigan, which is cool enough to take my breath away. You will be able to see right through it and it will be topped with a copper cap. Down at the bottom of the neck Bruce will affix something in white with all thee of my initials, "CMM" to make sure everyone knows its mine. But that is coming down the road.

Next, Bruce is going to bend the sides the old fashioned way. That will be something to see. Then it will be time for some glueing up that will make it all look at lot like a guitar. I can't wait! Come back and watch!

3 comments:

  1. You lucky duck....this looks like so much fun. When I lived in Berlin I almost had to chance to build a guitar...but the time constraints did not allow me and I am sure it would of played like the plastic kiddo versions! LOL So nice to be around so much talent in one day! Mary

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  2. watching and suspense is building.....

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  3. Beautiful instrument for a beautiful man. Sas

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