August 2011 – Ervin Somogyi

FAQ #1: The Stiffness Factor

August 8, 2011

I do as much writing for website guitar discussion forums as I can, in addition to answering questions that people email me personally. I can’t really keep up with this demand very well, especially as so many of the questions are duplicates and I wind up giving the same answers over and over again. So I thought that I could eliminate a lot of this repetition by posting some of the questions I’ve gotten, along with my answers. Here’s one such:

Q: In The Responsive Guitar book you go to great lengths to discuss importance of and your method for top “stiffness testing”. I realize you would not want to divulge the optimum number you look to achieve for your guitars. Could you give us a range of numbers that you see from you experience that a new builder could use as a starting point?

A: Yours is a good question. To my mind it’s not so much a question of there being a “right number” or “right quantity”, as finding a method that delivers that information in a way that the brain can take meaningfully. In our culture, weights and measurements and statistics are how such information is most easily taken in and digested.

In other times and other places, however, the same information was transmitted differently, using different language and different tools. But it was the same information. One alternative method that I learned (from master luthier Jose Romanillos, who is certainly a traditionalist in the school of Spanish guitar making) is the following:

Take your joined top plate and start to thin it. It doesn’t matter if you do this with a plane or with a power sander. It is only necessary that you thin evenly, and not leave the plate full of lumps and low spots. Flex it from time to time to get a sense of its stiffness along the grain. Stiffness along the grain is considered the most critical indicator of where you want to wind up, as opposed to strength across the grain or diagonally to it.

You’ll notice that the plate is stiff, of course. How stiff? Well, stiff enough so that when you are pressing your thumbs against one side while holding onto other side with your fingers, and are bending the plate by pushing it with your thumbs, you will find that the spot that your thumbs rest against will be resistant. It will be resistant to the extent that if you keep on pushing so as to bend the plate, it will crimp at the points where your thumbs are. That is, you will induce a bend at those points that is different from the bend that the wood will take between those points.

That tells you that the wood isn’t ready to bend evenly yet. Keep on removing wood. By the way, if you’ve read my chapter on the Cube Rule you’ll understand that removing seemingly small amounts of wood will make a huge difference in the wood’s measured stiffness. So don’t hack a lot of wood off too quickly: go slowly and methodically.

Keep flexing the wood and removing wood. There will come a point at which the wood will “relax” in your hands and, when you press on the long axis with your thumbs, the board will begin to make an even arc along its entire length. It’s not fighting you.

That’s your starting point. No fancy equipment other than your hands and fingers, and a bit of sense of the wood, is needed.

You can of course keep on removing wood, and you can do so until you’ve reached a threshold on the other side and rendered the wood too wimpy to be useful on a guitar. (At the extreme, you can imagine how relaxed and unresistant a paper-thin slice of wood would be, right?) Your next twenty years can be happily spent exploring the range between these two extremes — which define a range of thickness that’s probably on the order of 1/16 of an inch. It’s pretty amazing what a few thousandths of an inch can do — and that’s not even considering the possibilities of selective tapering, bracing, and thinning!

The REMFAGRI Factor in Lutherie

August 8, 2011

I teach an annual week-long class in Voicing The Guitar. Some of my students have told me, in retrospect, that they were not prepared for the kind of class that this actually is: a few days into the class, after we’d discussed basics such as the physical properties of woods and the main modes of vibration, they’d begun to wonder exactly when I’d get around to saying anything really important — such as the essential secret techniques I’d perfected over the years, along with the requisite correct specific measurements. It would be at about the third day, when various items of information had begun to connect, and pieces of the puzzle had begun to attain unexpected significance, that these good people began to see that I’d actually been giving them pertinent information all along. It simply hadn’t looked like any useful information they’d ever been given before and they hadn’t recognized it as such. They had, instead, all been waiting for the secrets of the remfagri to fall into their laps.

REMFAGRI is my personal shorthand for the idea of a Recipe-Method For Achieving Great Results Immediately. It’s much like the idea of, say, the perfect recipe for French onion soup: it doesn’t exist, and never has, but that hasn’t stopped people from seeking it. It’s well known that some chefs make absolutely heavenly French Onion soup — but there’s ALWAYS another recipe out there that might be even better, if one is willing to keep on buying cookbooks… even though the recipes ALL depend on the same basic ingredients and techniques.

It’s hard to know whom to blame for our collective focus on REMFAGRIs, but they are endemic and epidemic. One has only to go to the nearest bookstore and look at the How-To and/or Self-Help section. No subject is left unsimplified, and even ungodly complex projects such as wars and choosing mates are conceived out of the same here’s-how-to-get-the-job-done mindset.

I’m inclined to believe that what is missing in general is any sense of… well… scale. The kind of thing that induces some personal humility and awe. You know, something should I put it… profound… or at least greater than you… and worth approaching with respect… rather than it merely being an extra-large-pizza-sized chore or challenge to deal with before you check it off your list and go on to the next thing to conquer. If you react to a sunset, or the great outdoors, with any sense of it being special you’ll know what I mean. And my question is: did you ever pair that sensation with doing any of your work, or learning anything, or having a discussion with someone? When do we ever think, or do, or meet, or eat, anything that we consider to be special?

These are nutshell descriptions of Life-Attitudes that are so fundamental to one’s thinking (or absent from it) that one doesn’t usually have an awareness of having such an attitude. It’s of course expressed in humor, which every culture has its own spin on. American humor is no less complicated than anyone else’s, but an awful lot of it is about belittling, diminishing, or simplifying what’s in front of us — and thereby reducing its scale, importance, or specialness.

It’s understandable that this should be so, given all the pressures of our contemporary lives: it’s tempting to find projects and relationships that we can exercise our powers over so that we can feel in control. And then, most cultures and religions (including all the secular ones) DISCOURAGE questioning of their basic beliefs. Doing so makes people uncomfortable (I mean, it’s sooooo intolerable to suspect that even French onion soup might be bigger than we are, no?). But, heck, let’s face it: we can’t even really comprehend basics such as gravity, amoebas, or trees. What’s wrong with admitting to some sense of scale?