Woodworker's Journal winter-2009, страница 33
Marking gauge layout lines, slightly irregular dovetails and square drawboring pegs are telltale signs left by the hand of a craftsman. on the table. Be sure to hide sapwood or turning flaws by positioning that spot away from view on the table. Lay out the mortises as shown in the Elevation on page 34, and scribe a line down the middle of each mortise layout to help you position the entry point for the drill bit. Clamp a fence to your drill press table to center each mortise under the bit and set the drilling depth at 15/16". Now drill holes at each end of the mortise layout, then drill out the rest of the waste (see photo, page 31). I leave about 3/16" between the first set of holes, then come back and drill out the small bridges. Drilling this way keeps your mortises straight and square. Chisels will make quick work of cleaning up the mortises. Drill peg holes in the legs. Machining the Side and Back Aprons Cutting tenons on the side and back aprons (pieces 4) is done with a table saw and a 1/2" dado blade raised 1/4". Set the fence 3/8" from the blade to yield 7/8"-long tenons. Make test cuts in scrap until you get a nice slip fit in a leg mortise, then cut your table pieces. Once the cheeks are cut, raise the blade height to 1/2" and cut the edge shoulders. To cut the double stub tenons on the front rails (pieces 3), set your dado blade height at 3/8" and cut the outside cheeks (see Elevation Drawing, page 34). Cut the 5/8"-wide gap between each pair of tenons with a hand saw and chisel. Now install a l/4"-wide dado blade and raise it 1/4" to rip a groove in each side piece 1/4" from the bottom edge. Next, clamp a wood face to your fence, slide the fence up to the blade and rip the edges of each drawer runner (pieces 5) to form l/4"-thick tongues. Assembling the Base It's time for a test-assembly of the table base. Fit the major pieces together and, if the joints are too tight, check the tenon edge shoulders first — that's usually where the problems are. If the joints are loose, shim the tenons to achieve a slip-fit. Mark the members of each joint with a letter to make reassembly easier. With the table fully assembled, use a 1/4" center point drill bit to mark the drawboring holes in the tenons. Slip the bit into each leg hole and tap it with a hammer. Disassemble the table and you'll see the marks left by the bit. Now use an awl to make new marks next to the old ones 1/32" closer to the tenon shoulders, and drill these locations with the 1/4" bit (see Detail on page 34). Use your drill press to assure straight holes. To mimic the old-time look of square pins, use a 1/4" chisel to square the holes in the legs to a depth of 3/8". The way to prevent tearout during this step is to make a scrap tenon that fits in the leg mortises and be sure to back up the tenons with another scrap piece. When the joints are reassembled the holes won't line up. However, when the pegs (pieces 9) are driven in, they will draw the tenoned pieces tightly into the legs. These are drawpinned joints. To make the pegs, rip stock into 1/4" x 1/4" strips and cut these strips into l%"-long pieces. Leave the first 3/8" of each piece square, then whittle the rest of the peg round (see Peg Detail on page 34). Taper the end of each peg to make driving easier. Before assembling the table base, drill expansion holes in the aprons, then fixed holes in the upper front rail for attaching the top. Use a 3/4" Forstner bit to form pockets for the screw heads in the aprons, drilling at a 10° angle, followed by 3/16" pilot holes. In the upper front rail, drill countersunk 5/32" pilot holes for screws. Gluing Up the Carcass Now glue up the carcass in three stages: first the front legs and rails, then the back assembly, WINTER 2009 33 |
