An interesting thought occurred to me during the summer of coffee tables. Namely, how do you attach a table top to a table base?
Oh, this sounds like a total Zen master type question. Kind of like what is the sound of one hand clapping? You just nail that sucker down to the base and … oh, wait.
Didn’t we once establish on this blog that wood moves due to changes in humidity? Oh, yeah, we did.
So, if you lock a wide table top down to a rigid base, there’s a chance that it could split due to differences in grain orientation and if you have not accounted for wood movement in your design. Believe me, you do not want to glue a breadboard end the entire length of the piece. Wait a few seasons and craaaack…. you got it.
So, what are some ways you can get around this? There are more than a few options available to you. For instance, a few years ago, I built a trestle-based work table, I captured the top of the trestles in between two battens screwed into oversized holes. The top of the trestle simply rested between the battens and a dowel pin held it in place. Simple, elegant, and it allowed for movement.
Another technique I used on the Cotterman. Basically, I screwed the table base directly to the top using pocket screws, but only on the sides of the table which paralleled the top’s grain. Since wood moves very little along the length of the grain, socking it down in that direction provides little in the way of cross-grain issues. That means I used just one screw on the short cross pieces of the table right in the middle to hold the top flat across its width.
For the round table, I turned to a mechanical fastener known as a z-clip. Either you can cut a saw kerf (or do what I do and use a biscuit cutter to make a small kerf) in the table supports. One end of the clip wedges into the kerf while the other end is screwed into the bottom of the table. In this arrangement, the top is free to move, and the z-clip pivots to allow the board to move.
Sure, it may take a little bit more time and effort to design the table to accomplish these goals, but believe me, after all of your hard work and effort, you will be happy that you took the time.