Monday, September 16, 2013

Dovetail joints and other things that come together and become strong

In the old days, cabinetry was actually called ‘joinery,’ because at it’s heart, that’s what it is – putting pieces of wood together in as permanent a way as possible.
And so we have been learning the fundamentals of that process, beginning with mortise and tenons (through-mortise, haunch-mortise and stop-mortise) – a basic, fundamental joint that looks like this:

A day after that, we had our first lesson on dovetails. And many of us, including myself, slept restlessly the night before. It’s intimidating. Dovetails are simple, yet complicated, fragile, yet incredibly strong when mated, and though many amateur woodworkers claim to be able to make them, few have mastered the skill.
Of course, our instructor Jim Budlong made it look easy, marking out, sawing, then chiseling a set of near perfect dovetails in front of the entire class, in about 20 minutes.
Instructor Jim Budlong demonstrates proper dovetail-technique. True story: He once tried to mess up his dovetails in order to show the class how to fix them -- but accidentally made perfect ones. Amazing.
It took the rest of us, and myself, much longer to get anywhere near acceptable, let alone perfect.
A dovetail joint is considered a ‘mechanical joint.’ It’s called that because two pieces of wood are held together not simply by glue or dowels, but by a series of pins and tails that lock together in such a way that the pressure exerted on them, say in a dresser drawer, actually serves to make the joint tighter over the years, not looser.
But because of that, they are difficult to make, with complicated angles and often dozens of surfaces required to meet perfectly in order for the join to look good.
There’s a reason perfect dovetails are seen as a mark of true craftsmanship, even though they are usually hidden away in the back of a drawer in a cabinet or dresser. When done well, they are sophisticated, beautiful, and add strength and durability to a piece of furniture for decades, even centuries to come.
Done poorly, they can cause fractures or cracks as the two pieces of ill-fitting wood are forced together. If the dovetails themselves are too small, too thin, their strength gives way to fragility. If the dovetails are too large, too evenly spaced, or poorly laid-out, they become clunky and awkward to the eye regardless of how perfectly they were cut.
In the examples we were shown from past years’ students, there is one that was particularly disheartening. A set of dovetails, perfectly cut, fitting together like a glove, were labelled by some heartless instructor as being “too perfect, looks machined.” Unbelievable!
A dovetail, at its best, is not cut on a router jig or by a giant machine in a factory somewhere. Rather, it’s the work of a careful craftsman who cares about little details, such as the size of the pins and the fact the pins on the outside of the joint should be closer together than those on the inside, because there is greater stress.
A craftsman knows these things and takes them into account, and the final product reveals that. A drawer cut by a machine simply doesn’t have the same effect. Or at least that’s what we’re being taught, brainwashed really, as our instructor joked recently.
I’ll take it. The challenge is fun, despite the frustration, and getting it right in the end is so worth the effort.
And the hope is that all these various components of our woodworking education, from sharpening to tool-making, planing and joinery, will all add up and eventually come together, like the two sides of a dovetail joint, and create a firm, long-lasting bond that will only get stronger in the years to come.
Some of my many dovetail attempts!

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