I recently put together a box joint jig for the PaxSpace router table. Box joints are used to join two pieces of wood using interlocking fingers- for things like drawer box corners, for example. Box joints can look good, especially with contrasting wood types. The joint is also strong, even stronger than more complicated dovetail joints when using modern glues.
The jig was made using scrap pieces of 3/4″ MDF for the main jig base, a piece of 3/4″ plywood for the front fence, and some scrap oak for the indexing guide pin and miter slot runner. The basic design was copied from this YouTube video.
One of the differentiating features of this jig is the microadjustment screw that is attached to the sliding fence face. The screw allows the jig to be adjusted by a fraction of an inch in order to loosen or tighten the resulting fingers and gaps. This turned out to be a good thing, because the initial setup of the jig made two pieces that were so tight that I couldn’t mate them together. I made a small adjustment to the screw to make the finger gaps a hair wider, and everything works like a charm.
Here are the first test cuts with some scrap pieces of wood:
Not too bad. Now I just need to find a project to use some box joints on!