Wi th the sides down, the top of the Pembroke table appears to be circular.
Once the leaves are raised, however, the top’s distinctive shape, with elliptical ends and sides, becomes apparent. Similar-shaped tabletops were used on Federal-period card tables. The leaves are hinged on a rule joint, which is shaped on the router table. Once the joint is completed and the hinges located, the curved profile of the leaves is cut on the band saw.
Routing the edges of the tabletop
Clamp the tabletop to a work surface with the edge to be shaped extending off the surface. Install a piloted round-over bit and adjust the cutting depth to allow you to reach the final
depth in at least two passes. As you make the cut, press the bit pilot against the stock throughout the pass (above). For a smooth finish, make your final pass a slow and shallow one.
2 Routing the cove in the leaves
Install a piloted cove bit in the router and mount the tool in a table. Align the fence with the bit pilot bearing so the width of cut will equal one-half the cutter diameter. Clamp a featherboard to the fence on the infeed side of the bit to hold the workpiece flat against the router table. Set the depth of cut shallow to start; make several passes to reach your final depth gradually. Feed the leaf into the bit, pressing the edge of the workpiece firmly against the fence (left). After each pass, test-fit the pieces until the top and the leaf mesh with a very slight gap between the two.
4 Outlining the profile of the top
Enlarge the grid shown in the inset to produce a cutting pattern for shaping the profile of the top; one square equals 2 inches. Trace the pattern onto a piece of 14-inch plywood or hardboard and cut out the template on your band saw. Then set the top face-down on a work surface and extend the leaves. Mark a line down the middle of the top and position the template on it; align the straight edge of the pattern with the centerline and the adjoining curved edge with the end of the top. Use a pencil to trace the curved profile on the top. Repeat at the remaining corners (above).
Cutting the profile of the top
Unscrew the leaves from the top and use your band saw to cut the curved profile into each of the three pieces. Cut just to the waste side of your cutting line (left), feeding the stock with both hands and keeping your fingers clear of the blade. Sand the cut edges to the line.
Using steel tabletop fasteners
Commercial steel tabletop fasteners work like wood buttons: They are screwed to the top from underneath and grip a groove cut along the inside face of the rails. Because commercial fasteners are thinner than lipped wood buttons, the groove does not have to be cut with a dado blade (page 33); you can use a standard saw blade or a three-wing slotting cutter in a table-mounted router.
To ensure proper tension, make the groove a little farther from the top than you would with the wood buttons.
Installing the top
The top is fastened to the table rails with wood buttons; screwed to the top, the buttons feature lips that fit into grooves cut into the rails (page 33), providing a secure connection while allowing for wood movement. Reinstall the rule-joint hinges in the top and leaves, and place the top face down on a work surface. Make a button for every 6 inches of rail length (page 133). Spacing them about 6 inches apart and leaving a ‘/e-inch gap between the bottom of the grooves and the lipped ends of the buttons, screw the buttons in place (above). Once all the buttons are attached, drive a screw through each corner block into the top.
BUILD IT YOURSELF
You can use pocket holes with screws as an alternative to wood buttons for attaching a tabletop to the side and end rails. The holes are drilled at an angle, and a pocket – hole jig (left, top), shop-built from %-inch plywood, makes simple work of boring the holes on your drill press. For the jig, screw the two sides of the cradle together to form an L. Then cut a 90° wedge from each support bracket so that the wide side of the cradle will sit at an angle of about 15° from the vertical. Screw the brackets to the jig base and glue the cradle to the brackets.
To use the jig, seat a rail in the cradle with the side that will be drilled facing up. Drill the holes in two steps with two different bits: Use a Forstner bit twice the diameter of the screw heads for the entrance holes and a brad-point bit slightly larger than the diameter of the screw shanks for the exit holes. (The larger brad-point bit allows for wood expansion and contraction.)
To begin the process, install the brad-point bit and, with the drill press off, lower the bit with the feed lever, then position the jig and workpiece to center the bottom edge of the workpiece on the bit (inset). Clamp the jig to the table and replace the brad-point bit with the Forstner bit.
Feed the bit slowly to drill the holes just deep enough to recess the screw heads. Then, install the brad-point bit and bore through the workpiece to complete the pocket holes (left, bottom).