I previously discussed how I plan to join the sides, web frame, and bottom shelf here, using sliding dovetails. They will provide a mechanically strong and invisible joint. Before cutting the dovetail dadoes, I carefully cut the sides to length using my table saw and sled, with the blade tilted the requisite 11 degrees. To locate the dadoes, I aligned the sides to the face frame and used a straightedge and marking knife to mark the position even with the tops of the rails.
I set up three routers with the requisite bits: 7/8″ straight, 3/8″ straight, and 3/4″ dovetail. The jig aligns easily with the knife mark on the sides (assuming you put it on the correct side of the knife mark!). I routed the 7/8″ dado first, after noting the rotational orientation of the router base in the jig. Because the base is never perfectly concentric with the bit, I wanted to make sure it was aligned with the dado already routed in the jig. A 3/8″ dado came next. That is done to make it easier on the dovetail bit; less material to remove makes for a cleaner cut. The dovetail bit was last.
After that, I cut the rabbet for the back to fit in, and trimmed the bottom corner of the rabbet with a chisel.
