Get a Leg Up on Fixing Wobbly Chair Joints

A wobbly chair is more than a nuisance, it can be an accident waiting to happen.

Because a chair’s strength depends on the firmness of all its joints, if one joint becomes loose the others receive extra stress that can loosen them also, possibly causing the chair to collapse.

Fixing wobbly chairs is usually easy if the problem is not too severe. But take antiques or fine contemporary chairs to a professional restorer; amateur repairs can lessen their value.

At the first sign of wobbling, examine a chair for the cause. If a joint is loose, try injecting glue into it with a glue syringe available at hardware stores. Use woodworking glue, technically called aliphatic resin glue.

Avoid pulling the parts of the joint apart to inject the glue; this usually loosens other joints. If necessary, drill a small hole into the joint for the syringe’s tip. Afterward, bind the chair parts firmly with string or rope or use a furniture clamp for about 18 hours.

To repair a loose chair rung, clamp the rung tightly in its socket and drill a quarter-inch-diameter hole at least two inches long through the chair leg and into the end of the rung. Apply glue to a dowel that has the same diameter as the hole. Hammer the dowel into place and then carefully saw it flush with the leg. Sand the dowel’s end smooth and hide it with a dab of finish.

Gluing alone will not fill gaps between worn parts. If the socket of a joint is enlarged, try tightening it by packing bits of matchsticks, toothpicks or sawdust into the fresh glue. Never fix a wobbly joint by installing a nail or screw. Eventually the joint will loosen again and repairing it will be more difficult.

If a chair part is broken or if the methods described above do not work, disassemble part or all of the chair to restore it. Remove any reinforcing nails, screws or braces (search for hidden ones covered with filler or wooden plugs); then tap the joints apart with a rubber mallet.

Scrape or sand old glue from the ends of the pieces and their sockets. Fatten a dowel or the stub end (called a tenon) of a rung by wrapping it with cotton thread or special metallic tape sold for the purpose. A liquid product is also available that swells wood fibers; it can be used in place of glue.

To make a square socket smaller, line it with a thin sliver of wood. To make a round socket smaller, plug it with glue and a tight-fitting dowel. When the glue hardens, saw the dowel flush with the surrounding wood and redrill a socket the correct size.

To repair a cracked part, gently pry open the split. Insert a toothpick or knife blade as a wedge, then apply woodworking glue with a small brush. Remove the wedge and squeeze the split several times until glue oozes from the crack on both sides, preferably along its entire length.

Wipe away the excess glue with a damp cloth or paper towel, then clamp the repair until the glue hardens.

If a chair wobbles because the legs are of different lengths, set it on a level surface to identify the faulty leg. Lengthen a short leg by fitting it with a furniture glide, saw off a small amount from a leg that is too long.

Chairs with padded seats set in a frame usually have reinforcing blocks where the legs meet the frame. If the blocks are wobbly, remove them, scrape away any old glue, and then reattach them with fresh glue and slightly larger screws.