Building Carcass Subassemblies
This sideboard’s case construction reminds me of auto unibody construction. Instead of the case being a frame supporting independent panels, the panels are integrated into the assembly to make it stronger and more rigid. Routed mortises and loose tenons join the posts and bottom rails, while dovetails join the top rails to the legs. The end panels are plywood, biscuited to the legs and rails. The bottom is plywood, biscuited between the bottom rails. Web frames in stopped dadoes support the drawers.
Begin building the case by cutting the joints that connect the rails to the legs, forming the framework. With a plunge router, edge guide and a shop-built mortising block, you can rout the following mortises quickly and accurately:
•Single mortises in the legs and bottom front/back rails;
•Twin mortises in the legs and bottom side rails;
•Single mortises in the legs and top side rails.
Next, construct the loose tenons and test-fit the joints, then cut short tapers on the legs and shape the bottom-rail arches.
Cut the plywood panels for the sides, bottom, partitions and back panels. Lay out and cut biscuit slots in the side and bottom panels, with matching slots in the rails and legs.
Go ahead and edge-band the partitions with strips of solid stock, then rout grooves in the rear bands to accept the back panels. I did this on the router table with a 7/32″ straight bit. While you’re set up, rout back-panel grooves in the legs as well as the back bottom and top rails.
After a dry-fitting to ensure the parts fit properly, glue up three subassemblies: two side units, each consisting of two legs, top and bottom side rails, and a side panel; and the bottom, consisting of the bottom panel and the front and back bottom rails.
Rout the shallow dadoes for the drawer dividers and runners next. These dadoes extend from the back-panel grooves to within 3/8″ of the front edge. To ensure that the dadoes would line up properly, I clamped the partitions edge-to-edge and used a long straightedge clamped across both to guide my router. Square up the ends of the dadoes with a chisel. Rout corresponding dadoes in the two side assemblies.
The two cupboard compartments (behind the doors) have adjustable shelves. Now is the time to drill the shelf-pin holes in the partitions and the side assemblies.
Notch the top front and back corners of the partitions to fit around the top rails.
The partitions are joined to the case bottom with biscuits. Lay out the locations and cut biscuit slots in bottom assembly and partitions.
Cut the web frame parts — drawer dividers, runners, rear rails and dust panels. Notch the front corners of the drawer dividers to fit the stopped dadoes. Rout the web-frame joinery: stopped grooves for stub tenons joining the dividers/rails and runners. Plow grooves for the specified dividers, runners and rails for dust panels. Glue up these frames.
Now move onto constructing the top frame, which consists of the front and back top rails and four top stiles. Stopped grooves and stub tenons join the top stiles and rails. A single dovetail connects these long rails to the legs. Lay out and saw the dovetails on the rails first. Then, dry-fit the side and bottom assemblies together, set the top rails in place and scribe around each tail onto the leg tops. I roughed out the sockets with a router and straight bit, then pared them to the final fit with a sharp chisel. Glue up the rails and top stiles.