Two jigs are used to add important details to the Keepsake Box in Woodsmith 275. The first one helps to rout the inner radii on the notch in the box front. The second one cuts the grooves for the splines in the mitered corners.
Radius Jig. The radius jig (shown above) is made of three pieces: two plywood cleats that straddle the workpiece and a hardwood strip with two radiused corners to guide your trim router. After cutting the pieces to size, I used a compass to mark out the radiused corners, then shaped them at the edge sander. Note that both ends are radiused. From there, glue the pieces up to form the jig. You can see how the jig is used below. First straddle it on the workpiece, then follow the radii with a 1⁄4" pattern bit. After routing the first side, slide the jig across to rout the other.
Spline Jig. The second jig cuts the slots for the splines in the corners. As you can see below, it takes four pieces to make this one. A piece of plywood acts as a large, auxiliary fence, while three mitered pieces of softwood (one in front, two in back) cradle the case as it makes the cut. After sizing these pieces (and cutting the miters on the cleats) glue them up, leaving 1⁄4" gap between the cleats for dust relief (as in the drawings below).
In use, the jig rides along your table saw’s rip fence (as shown below). After the clamps come off the jig, set it in place and align the fence to cut the first set of slots. Detail ‘a’ shows the blade height for these cuts. Set the case between the cleats, then make the first set of notches, pushing the jig through the blade and turning the case to a new corner each time. After cutting the first set of notches, adjust the table saw fence to set the jig up for the next series of cuts.
