Passing the point of no return

Tonight I joined the guitar top to the sides. This is a non-reversible operation, so if I messed it up, I’d be rebuilding a new top AND a new set of sides. Fortunately, it went relatively smoothly. I triple-checked the fit and alignment, did a little last minute trimming of a couple of braces, dry-fit the clamps before gluing, then pulled the trigger. Below are the before and after pictures – tomorrow I’ll unclamp everything and see how it all looks as a unit.

I feel like I’m on a bit of a roll now – a lot of design decisions have been made and committed to. Now it’s “just” about careful execution. I’m going to try to keep up at least weekly work on this through the holidays, when I’ll have a more concentrated span of time for shop work.

Ready for gluing

Ready for gluing

Glued, clamped, weighted down

Glued, clamped, weighted down

If at first I don’t succeed…

After fixing the guitar body lining that I messed up in my last post, I went back to the shop today (fueled up on delicious Thanksgiving leftovers) determined to slow down, get in the zone, and cut the notches in the lining they way they should be. In the end I decided to try notching the braces into the lining for structural reasons, not acoustic reasons. The acoustics, as I mentioned in that post, are a matter of debate – how tightly coupled the back and sides are to the top is a matter of taste and tuning. But I’d read stories of braces coming loose over time and vibrating – supporting the brace ends by tucking them into the lining seems to help, and that explanation made sense to me.

A few careful saw cuts and chisel strokes later,

Cutting slots (in addition to the full slots already in the lining to provide flexibility) for the sides of the pocket.

Cutting slots (in addition to the full slots already in the lining to provide flexibility) for the sides of the pocket.

Chiseling out the waste of the pocket to the depth of the brace. The end of a top brace will tuck into this pocket.

Chiseling out the waste of the pocket to the depth of the brace. The end of a top brace will tuck into this pocket.

I had six pockets routed out on both the top and back sides of the lining. A preliminary fit of top and back showed I was in the ballpark – I may have to trim a smidgeon here and there before gluing, but that’s better than removing too much all at once. There will be a little but of ugliness in terms of the visual presentation (in some cases it was easier and safer to just remove two whole segments of the lining to the correct depth, rather than try to saw and leave a very thin and weak segment), but most of this work is not visible to casual inspection. Again, “just build the damn thing.”

No particularly deep lesson today, just a reminder that failure is an opportunity to learn and grow. While I lament the fact that there is no easy “undo” in woodworking, it does slow me down and focus my concentration in a particular way, and gives me real “failures” to recover from.

Trying the NaBloPoMo exercise, 2014

My colleague Cynthia tells me that it’s National Blog Posting Month (NaBloPoMo), whereby we take up the challenge of posting once a day for the month of November. I have mixed feelings about this – do I really have anything worth saying/writing every single day? Well, this is one way to find out.

On the guitar building front – slow progress. I’m treating the body and the neck as two entirely separate build processes until the final assembly, and I’m glad I chose that path – having to integrate design choices for both body and neck simultaneously would have been overwhelming. The key parameter – the angle at which the neck meets the body – can be deferred and actually adjusted after the fact (to a degree, and about one degree is about all that it will take). Some quiet evening I’ll glue in the other set of lining strips, and then start the finishing work on trimming the brace ends and notching pockets in the liners to accept the top and back palates.

As I discussed in the past couple of blog posts, the process of working through the guitar build has been very different from crafting a symbolic work (an essay or computer program). Mistakes due to poor planning can be costly setbacks. This is another reason I’ve set the neck aside for a bit – I realized that, even on a rainy Saturday afternoon, I can’t simply go into the wood shop and “work on my neck.” I really have no idea what I need to do next, and before I take blade to wood I really need a plan.

If the neck were a piece of software I might try one or two different approaches (true up the sides first, then the figure out the right length and cut the body end square; or work on the heel first, and worry about the sides of the neck later?) If i didn’t like how one approach was coming out, I’d simply back out the process (“undo” the changes) and try another approach. Obviously, that won’t work with wood. As it turns out, I do have two necks to work with (the first had too many chips and flaws in the headstock, so I’m using that as my “rehearsal” neck), which gives me a bit of an opportunity for a “do over”, but I don’t want to squander it. If you knew you could only press the undo button once on a project, how would you approach things?

So I’ll stick with what is on my proximal horizon, finishing up the body. The logic and sequence of what comes next makes sense to me, and I can play around a bit with those choices.

Other themes I may write about this month: on the music front, I’m taking up Bach’s Chaconne seriously. I’ve doodled with sections in the past, but many of the passages (particularly the fast scale work in 32nd notes) have been beyond me technically. The Chaconne is really a rite of passage for serious classical guitarists, and is the piece my old teacher and I would have started working on next when I was graduating college. Working on it will provide a good vehicle for working on my technical weaknesses; I’d prefer to work on scales in the context of a musical composition, rather than as stand-alone exercises. And the Chaconne is simply beautiful.

On the work front, I’ve felt a bit like Cassandra this year, doomed to tell clients that their brilliant ideas are probably not going to work out as easily or well as they think, and then working on evaluations that prove me right. While I care about “making a difference” in education writ large (and what that means exactly will probably be the subject of many NaBloPoMo musings), I’m generally skeptical that the problems that matter call for technological solutions, at least in the limited “how can we substitute a computer for hands-on instruction” sort of senses that dominate the field.

This year has also opened my eyes to the inner workings of the medical profession, mainly by watching my partner go through some significant diagnostic challenges. If I can write about those insights while protecting her privacy, I will.

Well, perhaps I will after all find enough to write about this month. In the past this effort has petered off after a few days; to keep it going I’ll have to make a regular habit of writing before bed or at another set time of day.  Till next time!

Perhaps not bad, but different habits

In my last post I ruminated on some habits of mind I’ve developed over the years that are not serving me well in guitar building. In software engineering or other “symbolic” construction activities, we can undo our mistakes with a keystroke. Writing a paper is a bit like shaping bits of wet clay into a form; revising and editing is like shaping fine details. If we don’t like how something is coming out, we can scratch it out and re-do it.

In woodworking and other crafts, there is no undo button. Recovering and re-working a mistake can be quite time consuming. As I continue my guitar build, I pass several points of no return. If I take too much thickness off a side or plate, I have to start that piece over. If I bend a sharp kink into one of the sides, it’s unlikely I can un-bend it smoothly, and have to start from scratch on that piece. Once both the top and bottom are glued to the sides, there is no going back to tweak the interior bracing. The real hold-my-breath moment will come when I’m trying to fit a finished neck to a completed body – if I take too much material out of that joint while adjusting the angle, I’ll have to build an entire new neck.

Guitar making calls for a particular set of mental work habits. Critical among these is careful planning and execution of individual work phases. But that doesn’t make the way of the software engineer “bad” – rather, it’s an inappropriate set of habits for the job at hand.

Modern software engineering paradigms depend upon rapid iterations of design-implement-test cycles, with lots of throwing-out-and-redoing of code. See, for example, Agile Programming philosophy.

Professional software engineers have reflected on how programming lies somewhere on the span between art and engineering. In the arts, the creator is in constant communion with the medium, be it a canvas, manuscript, block of marble or code module. S/he works toward a goal, but there are always opportunities for the work to reflect back “hey, I’ve got a better idea!”  Good artists listen, appraise, and change direction in response to new revelations. Agile programmers follow a similar process with respect to both their discoveries along the way and the changing needs of their clients.

Woodworking can sit in varying spots of this spectrum as well, in some cases being more linear in process (think building a house), in others smack up against the arts end of the scale (starting with a chunk of firewood on a lathe, and ending up with a bowl). In the case of a guitar, there are strict constraints on certain design elements – the frets have to be spaced just so to produce well-tempered intonation (but see the fan fretted guitar for a clever innovation – retaining the relative fret spacing string-by-string but scaling each string to a different length). But there is also wiggle for late changes; on my current guitar, I’ve decided to alter the original plan for the neck-body joint. Rather than use the classical Spanish heel, I’m designing a bolt-on neck joint. Totally non-traditional in the classical guitar world, but this joint affords a lot of fine-tuning at a critical phase of construction (getting that angle right). For a relative novice luthier, having this flexibility is a gift – I don’t have to get everything “just right” several stages in advance, only to discover weeks or months later the critical mistake that has killed any chance of getting a playable instrument from the process.

The bottom line:  I’m not “bad” for needing to learn a different set of work habits when I close the laptop and put on the shop apron. These different habits of mind serve well under the appropriate circumstances.

Gluing a flexible lining along the top edge of the sides, to provide a better gluing surface for attaching the top.

Taming bad habits

I’ve been making slow, sporadic process on guitar #2, but the past few weeks have seen a burst of activity. The sides are bent, the top and back plates are braced, and I’ve just finished sanding a contour into the top edge of the sides to mate with the slightly domed top plate. Next up: glue the kerfing (liner) around the inside of the sides to provide a gluing surface for the top to adhere to.

Today I also shaped and scalloped the three transverse braces across the back plate. I noticed that one of them did not have a perfect 90 degree angle between the bottom (where it glues onto the plate) and sides – it was canted over slightly. But the braces end up trimmed in sort of a cathedral or triangular cross-section, so I figured I’d correct that by over-trimming one side to bring the two sides into symmetry. That worked, more or less, but then I found myself rushing the process a bit, having to then stop and fix some of the unevenness with sandpaper… all in all, it felt rushed.

A local guitar maker (a retired hand surgeon) once told me that building a guitar is like performing surgery: if you are careful in executing every step, you might get a good result. But if you rush or are sloppy anywhere, the probability of success drops off rapidly. My biggest problem is not getting into that Zen, slowed down, in-the-moment space before setting down to work. Today I was able to more or less recover from working too quickly, but it was a warning. My next moves have to be done with greater care – as the build progresses there is more and more to lose if things go wrong.

So much of my work in software was at a much higher tempo, in part because one can always “undo” mistakes with a keystroke. Woodworking – like surgery – requires a much more deliberative pace. I’m clearly out of practice with this habit of mind.

Shaping the spruce braces underneath the top plate with a tiny plane.

Shaping the spruce braces underneath the top plate with a tiny plane.

Committed to #002


I built my first (and only) classical guitar during my senior year in college. I’ve been feeling the itch to tackle a major project lately, and playing some high end guitars at local shops inspired me to take a second crack at it (having presumably learned something since my last attempt).

Since my last build, the Internet happened. Now I have access to several luthier forums where amateur builders can trade tips and tricks. Several amateurs have started their own web sites where they meticulously document their project (I don’t plan on being one of them, though – the market is saturated with those photo essays, and I’m more interested in documenting the inner journey). One professional luthier – J. S. Bogdanovich – has published a book, DVD series, and most importantly, full size blueprints of his design (my annotation of his top appears above).

So I’ve pushed the button – my wood is acclimating to the local climate, and I’ve purchased some of the specialized tools needed (e.g.,  an electric bending iron). Most of the work will take place at The Sawdust Shop, although some of the detailed hand work could just as easily be done on my dining table.

I’m hopeful that this will also kick start another round of blogging. A recent Facebook post by an old college friend mentioned a mid-life career crisis, and I was shocked at how many of our mutual friends chimed in “me too.” There is something about approaching 50 that makes one (or at least, me) take stock of what I want the next few decades to look like. Working with my hands brings me to a state of flow that I find hard to achieve otherwise; we’ll see whether any useful insights come from this next project.



Teaching first- and second-hand knowledge

I’m still ruminating on themes of “practice” and “mastery” I touched on in some previous posts. This blog is starting to serve as a “parking lot” for ideas that I hope to weave together into a more coherent form someday.

I’m not sure what exactly sparked off this latest thought, but I’ve been noticing the distinction between teaching first-hand and second-hand knowledge.  Teaching something we know first-hand is pretty obvious – I can teach a child how to tie a shoelace, or a colleague how to specify a statistical model. I don’t have to draw on external resources to provide the content, although teaching aids (pictures, text books, etc) can help embellish an explanation.

Secondary knowledge is something I don’t have direct experience with, and here it gets interesting.  Most of us adults (who aren’t professional historians) know something of the founding of the United States, the framing of the Constitution, the Revolutionary War, etc.  We can also tell these stories to our children, but how sure are we about the knowledge we’re imparting?  Telling any sort of cultural myth generally entails passing along a story or knowledge that one has not directly experienced; we serve as conduits for a communal story.

Okay, so far no problem – there are things we know directly (and teach/coach) and other things we pass along (such as historical narratives).  Now think of middle school science teachers.  Are they teaching primary or secondary knowledge? It’s an interesting question.  Many are probably generally well-versed in textbook knowledge (they may have even majored in a science), but to what extent have they internalized the knowledge as their own?  I could probably do a decent job of teaching a basic physics class, but I was never really a practicing physicist, and know little beyond the first year college course.  So what would I be doing, other than interpreting/explaining what was already in a text book? What would I add of my own?  And does it matter?

A while back a friend of mine asked me how to get rid of these whitish rings that had appeared on his dining table. I knew I’d read about those in a book on finishing, and sure enough I was able to look it up and respond with a remedy – try mild heat, and perhaps gentle abrasion with steel wool.  But I also warned him that I had never actually tried any of these remedies myself, so couldn’t vouch for them or for unforeseen consequences.  It was an unsatisfying experience.

In a similar vein, I’ve certainly read about wood movement (the tendency of wood to expand and contract along particular dimensions with varying humidity) and how to design for it, but I’ve never actually experienced, say, a panel blowing out of a frame or a drawer getting stuck in its casing.  On the other hand, I’ve both read and experienced what can happen if an off-cut catches the back part of a spinning table saw blade, or what a bowl feels like as it flies off of a lathe and into my face shield. I know that you shouldn’t brake around corners on a fast mountain bike descent, and I know why you shouldn’t do so (having done it and experienced the consequences).

So back to my question: when does it matter that a teacher possesses first-hand, experiential knowledge of a subject, versus largely second-hand, “received wisdom?”  We intuitively prefer the former, and I suspect there are varying degrees of the latter. That is, I was never a math major, but have a reasonable intuition about some aspects of middle- and high-school math.  I certainly know real-number algebra inside-out.  But – although I took a course in abstract algebra as an undergraduate – I know I don’t have the deeper connection to theories of algebras, how systems of domains and operators come together coherently. So I can help a high school freshman struggling with his or her algebra homework, but there are limits to what I can teach.

I’m starting to examine my own balance between first- and second-hand knowledge, both at work and in general life. It’s starting to feel like exploration – we go out and cover some territory, come to know it well, but hear from fellow travelers about what lies over the next hill.  Perhaps we even pass that folklore along to others, along with our own hard-won knowledge of familiar terrain. And we make judgments about risks – the consequences of mis-informing a fellow traveler about the safety of that frozen river, for example, could be catastrophic.

As I wrote, this will become a thread I’ll broaden and deepen; it weaves through a number of areas of my life/experience.