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 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!

Wednesday, March 5, 2014

Sucky Weather Does Not Stop Guitar Building!

Here's this first. Guess what it is:

That's where the hole in the middle of the front of a guitar comes from, which a lot of people call "the sound hole," but actually, it's the air hole that lets the top, back and sides vibrate in the lovely way that creates the guitar sound. More on that much later.
Bruce Roper, the luthier at Old Town School who is making a guitar for me, cut this sound hole from my sapele guitar top Wednesday morning in a series of meticulous steps that also included building a rosette that encircles the hole. I'll show you that in a bit.

What a ghastly day! The car went to the Botanic gardens with my wife and her good friend, and I packed my camera and stuff into a backpack and headed for the CTA so I could get to Bruce's workshop and move things along on the Buildmyguitar project. It was not an auspicious morning. My fancy tripod fell out of my backpack and the top snapped off as it hit the ground. Amazon is sending me a better new one. I am sending them money.

Bruce lives and works in a neat little space down near Lincoln and School, where he has his apartment, his recording studio and his guitar repair and building shop. To get there, I have to go to from South Boulevard in Evanston to Belmont and then cross over and get the Brown line and go backward a little bit until I get to Paulina, which is the stop for Bruce's place.

I don't mind the trip at all. It's snowy and everything that was dingy, frozen and gray just a day ago now has a mantle of fresh snow to perk it up for a while. It's great to look at Chicago from the El. I used to take it to work every day when I first joined the Tribune in 1979. I thought of it as a very romantic ride past the lives that countless thousands of Chicagoans had built over time.
 I would write poems in my head on my way to work. It is an easy city to fall in love with, despite its challenges.

Bruce was shoveling snow when I got to his shop (after a stop at Wishbone for a coffee and a biscuit and some bacon). Cheery about it all, he unlocked his shop and led me in. What a vision.

What you can see here are the fiberglass splints Bruce uses to hold the glued bracing down against the back of my guitar. What you don't see is that the guitar back is sitting on a piece of wood that has just the slightest curve in it so that when the whole thing dries, the back will have just the hint of an arch in it. All my guitars have that and I have seen how it is done at Martin's Nazareth factory and at L'arrivee Guitars in Vancouver. But this is how it's done in a small shop that has no fancy vacuum presses or lines of guitar builders. It's just Bruce and the wood. But he has his ways.

The braces need to be held down with even pressure all around so the top shapes right and they do their job once the instrument is assembled, adding lots of strength to what is basically a fancy, thin hardwood box in this case. Bruce used a belt sander to shape the braces before he glued them down. There is a reenforcing strip that runs down the middle, holding both sides of the back and the strips of walnut and sapele that run down the center of the back in solid place. Those orange sticks are fiberglass Bruce bought at a home repair center. They are wedged up against a piece of plywood that hangs above the workbench. It's a smart way to do the job.

But I would learn Wednesday morning that there are a lot of smart ways to do the job when you work alone. Bruce will teach you how to make a guitar in his guitar building class, but mostly he is working alone. He has just two hands and lots of tools to help when he needs them. You learn the value of practice when you watch him at work.

The challenge today will be to cut the trench for the rosette around the sound ("air"?) hole in the center of my guitar, then to cut the actual hole. This is delicate work with a high potential for creating disaster unless you know what you are doing. Bruce knows what he is doing. First, he marks the top so it has the same measurements as the 1939 Gibson Nick Lucas that was the model for this guitar.

Bruce is using a compass to draw the circle he will follow to dig the channel for the rosette he is building for the guitar. The pattern is tortoise shell, green wood and then another strip of tortoise, very simple and quite lovely. First that gets cut.

He is using a Dremel Tool with a hole cutting jig and a special bit that does the trick (but can cause some problems in wood that is so hard.) Looking closely, you can see the inside line he will use to make the actual hole. The rosette trench has to be cut first, then using the same axis (a pin that sticks up through the top of the guitar right in the center of what will be the sound hole) he will cut the hole. Everything about this part of the guitar depends on that center pin. If that is setup correctly, the geometry of the hole and its rosette will be perfect. It takes a couple of passes to make sure the trench is cut to the proper depth. It's careful work. You can't make it too wide or there will be an unsightly gap around the rosette on the outside. Too narrow and the strips used to make the rosette won't fit.
He doesn't actually pronounce the work done. He just takes the three strips and sets them in the little trench, starting at the northern most end. They fall perfectly into place. When he has pushed them all into place, he trims the ends and there you have it. The first part of the process is done!

See how they fit down in there? The next step will blow the brain right out of your head, as it did mine. Bruce gets those strips down in the channel, pushes them down to make certain they are in place and the grabs....guess what? A. glue made from horse hides. B. glue imported from distant Asia made from the carapaces of beetles C. Elmers. D. Can't say?

Superglue. That's right, Superglue.

Here is what it is doing. If you have ever seen a plumber sweat a copper pipe and then let the solder draw itself into the gap, you will get this right away. The Superglue, being super, does exactly the same thing. It seeks out every gap, every spot it can find, and sinks in. Because Bruce wants this part to go quickly, he is not happy with the ten seconds you have to wait for Superglue to dry. He has a drying agent he sprays on it. It sets and there you have it, a near perfect rosette ready for sanding.
He has to sand it because its not exactly level with the guitar top in some places. It will be soon.

He's taking a belt sander with fine grit paper to the rosette. It cuts it all right down to the surface. "You always have to keep it moving so it never has a chance to scratch into the surface of the guitar," he says. It takes just a few minutes and what comes out of it is wonderful.

Next, back to the center pin for five passes with the Dremel cutter again. Each time, Bruce takes just a tiny layer of wood away until the center finally rotates on its own. This day's work is just about done.
Here is how it looks:

Next step: top bracing, then bending the sides and moving toward some serious gluing!
Stay tuned.