• Loose Joints

Seat frames are held by mortise-and-tenon joints (a prong or tongue or wood secured in a hole in the joinining piece) or doweled joints (pegs of wood hold the pieces together) supported by triangular glue blocks notched to fit the legs. If you catch a loose joint in time, repair it with glue. If the joint is broken, you'll have to disassemble it and replace the dowels. The triangular glue blocks will probably be glued and screwed to the frame, and the dowel joint might even be supported with hidden nail or screw fasteners. Separate the joint carefully with an old screwdriver or a stiff-bladed putty knife, then replace the dowels. Make sure the joint is clean and dry before you reassemble it.

• Loose Legs, Rungs, and Spindles

Loose legs, rungs, and spindles can sometimes become loose on wooden chairs that are used excessively. But those problems can often be repaired.

Loose rungs or spindles -- and, where no bracing is used, loose legs -- can sometimes be mended by forcing glue into the joints. But a part mended this way may work loose again. For a more permanent repair, carefully separate the part from the frame. If both ends are loose, remove the entire piece. For very stubborn joints, twist the part slightly to break the glue bond; if necessary, use self-locking pliers. Pad the part to prevent damage to the wood from the pliers.