The hardest thing about dovetailing isn’t the sawing or the chiseling or the layout.
It’s the seeing.
I don’t think I can teach anyone to see, but I can show you where to look. Developing your eye , plus your ability to sense the perpendicular , will do more for your dovetailing skills than any jig, square, knife or saw.
Like everything with dovetailing, it all begins at the baseline , the thin scratch across the grain that determines the limits of the joint. When you remove the waste between the tails and the pins, a frequent error is to leave too much material behind, which prevents the joint from closing.
You need to be able to glance at the joint and sense immediately if the baselines on the front and back of your workpiece line up without any waste between them. Ian Kirby and other woodworking instructors recommend using a small square to probe the joint and look for humps and bumps.
I have never had much luck with the small square approach. If I have to probe a joint, I’ll do it with the long side of a chisel and see if the tool rocks back and forth on anything. Then I use the same chisel to tease out the garbage.
But it’s rare that I ever do that. Instead, I hold the board up to eye level and take a quick look. After enough dovetails, you’ll see it and know exactly what to do.
And the truth is, I rarely have to do much to my baselines except chase some little bits of junk in the corners. And that’s because I have a good sense of the perpendicular. We’re all born with it, but it’s like a muscle. You need to work at it.
When I’m chiseling out the waste between my tails and pins I hold the chisel at 90° to the work and stand to the side of the tool to ensure it’s at 90°. Again, other woodworking authors recommend you use a square or even a block of wood clamped to your baseline as a reminder. But this is really a “Use the Force Luke” moment. You know 90°. Just position yourself so you can see it.
(Quick side note: The more hand work you do, the more you’ll find this comes in handy for boring and mortising especially.)
The other time this sense of 90° comes in handy is when you are sawing your pins out and the waste blocks on the ends of your tail boards. A pencil line or knife line is handy, but the real guide is your gut. You’ll know when things are going wrong, even if the line is covered in dust.
Once you start developing these two skills you’ll find that you can put your winding sticks away when processing boards with your handplanes. Your sense of square will show you the high spots in a board at a glance.
This blog post is not brought to you by the High Times beauty pageant. Promise.
– Christopher Schwarz
You may also be interested in the “Mastering Hand Tools” DVD from Christopher Schwarz.