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Fine Woodworking Magazine Attaching Tabletops Three methods for controlling and directing wood movement Attaching a top to its base is a critical aspect of table design and construction. Regardless of the method you choose, it should meet the following criteria: The top must be firmly attached to the base; the top must remain flat; a solid-wood top must be allowed to move seasonally; the attachment method shouldn't compromise the design of the table or complicate its construction. I'll describe three ways of attaching a tabletop that meet these requirements, along with the reasoning behind each method. Controlling wood movement While you cannot prevent a solid-wood tabletop from moving seasonally, you can direct this movement so that it doesn't disrupt the looks or the use of the table. Below are examples of how to secure the tabletop to the frame to control expansion and contraction.    1. Pocket holes  This method is probably the oldest way of attaching a tabletop. It involves drilling into the rail a 1/2-in. flat-bottomed pocket hole at a 10° angle. Then a smaller pilot hole (to accommodate the shank of a #8 wood screw) is drilled into the center of the pocket hole. Common on antique furniture, pocket holes make no allowance for wood movement, which may explain the number of cracked and split tabletops. On small solid-wood tops (up to 9 in.) or veneered plywood tops, pocket holes can be the only attachment method. On larger pieces, they should be limited to areas needing movement restricted.
 2. Metal table clipsThese clips, also known as S-shaped clips or simply as tabletop fasteners, are probably the easiest and quickest method for attaching tabletops. They fit into a groove or slot cut on the inside face of a rail. The easiest method is to cut the grooves in the rails on the tablesaw. The grooves must be cut before the base is assembled. The clips are installed after the base has been assembled. Place one end of the clip into the groove and screw the other end into the underside of the tabletop. Because the groove runs the length of the rail, any number of clips can be used. This method nicely accommodates any cross-grain wood movement whether the clips are parallel or perpendicular to the tabletop's grain: The clips on the end rails move along the groove as the wood moves, while the clips on the front and back rails move in and out of the groove. An alternate way to install the clips is to cut slots in the rails using a biscuit joiner. This method removes less wood from the rails, and it has the added advantage of being doable after the base of the table has been glued up.
 3. Tongue-and-groove blocksThis type of fastener is made from project leftovers. These blocks are attached to the tabletop with screws and have projecting tongues that engage corresponding grooves cut into the rails. The rail grooves are slightly larger than the width of the blocks, allowing for movement and preventing the tabletop from splitting. By carefully laying out the placement of the blocks and milling properly sized grooves, a more tailored and carefully crafted appearance is achieved. The best way to cut the grooves is with a router guided by a fence bearing on the rail. Properly spaced, tongue-and-groove blocks work very well for all sizes of tabletops.
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