Sometimes I make 6- or 8-sided frames, reinforcing the otherwise weak joints with splines. As when splining square frames, these polygons are first glued together, and then the frame is held vertically in a jig and fed across the tablesaw to cut the spline slots.
The trick is in the jig. Many woodworkers have a dedicated jig for spline-slotting square frames. It’s typically constructed somewhat like a tenoning jig, except it has two fences–perpendicular to each other and at 45° to the saw table. These are usually screwed to the jig face. Instead, I attach my fences with double-faced tape rather than screws. This gives me the flexibility to attach or rearrange any type or number of fences to suit a frame of any shape. (I can also use the jig for tenoning by attaching a single vertical fence.)
The jig itself is nothing fancy–just a couple of 3⁄4"-thick MDF or hardwood plywood panels attached and gusseted at a perfect 90° angle with a handle on the base for keeping the jig against the rip fence when in use. For safety, always clamp the workpiece to the body of the jig when sawing.
-Bill Sands, Lubeck, West Virginia
