How to Build a Simple Box-Joint Sled
The strength and style of finger joints come easy with the straightforward sled
Synopsis: Doug Stowe’s box-joint sled makes quick work of finger joints and it’s easy to build. It starts with a small crosscut sled for the tablesaw. An adjustable board with a hardwood pin glued into it is attached to the fence, and after it is fine-tuned to cut perfect sized finger joints, can be reused time and again with the same blade. Stowe shows how to make the sled and how to use it to cut test joints, fine-tune the fit, and make perfect box joints every time.
Finger joints, also called box joints, are incredibly strong thanks to all their long-grain glue surface interlocking finger by finger. But these joints have distinct advantages beyond strength. Once you have a jig set up, they are quite quick to make. And the pattern of end grain vs. side grain at the corners creates a pleasing visual rhythm. The joint also can be scaled up, as in some Greene and Greene pieces. Luckily, finger joints offer all this while being very easy to cut.
While you can make finger joints using a jig clamped to the miter gauge of your tablesaw, a dedicated sled is the better choice. Because it has two runners instead of the gauge’s one, it provides a more stable and reliable platform.
A standard combination blade will work, but if using a single blade, I prefer rip blades because of their flat top, which leaves a cleaner joint than a combo blade’s alternate top bevel. Similarly, for fingers wider than a standard sawblade’s 1⁄8-in. kerf, you can use a regular dado stack, but I like box-joint blade sets, which come with a pair of blades that leave a flat-topped kerf in two fixed widths. Alternatively, you can send a typical dado stack to a saw…