What to Do When You Can't Keep the Legs of a King Size Bed Tightened
If the stems of the legs on your bed frame bend or the holes strip, the legs will loosen and fail. Beds without adequate support, including loose or missing legs, void the manufacturer's warranty. Mattress companies require that a king-sized bed frame has five to six legs to provide adequate support for the mattress and foundation. Unless you fix or replace loose legs, lack of support will eventually damage your mattress or foundation.
Drill New Holes
Moving the bed around causes the legs to wiggle and loosen. If you do not tighten them right away, the stem that holds the leg in the hole rocks back and forth. This movement eventually enlarges the hole, making the leg wiggle even more. Eventually, the stem either strips or bends and the leg fails. Drill a new hole about 1/2-inch from the old one, if space permits, and twist the leg into it. To eliminate the old hole, fill it with wood putty or carpenter's glue, then drive toothpicks or a wooden plug cut from a piece of dowel rod into it.
Replace Bent Stems
If the stems on the legs bend, they will not tighten correctly. Even if they jam in place, the angle puts added force on the stem, causing it to bend even further, until it snaps or the wood around it splits. If the stem screws into the leg as well as into the bed frame, you can twist it out and replace it with a new one.
Replace Split Legs
If the leg has split, the stem will not stay in place. Split legs might break if more than one person sleeps or sits on the bed at the same time. Use the same type of leg if you want to replace just one, or switch to glides instead. Some glides are a single piece. Others have a top piece that twists into a base plate that you attach to the frame of your foundation and a bottom piece with a soft foot, according to SleepLikeaBear.com. If you switch to glides or use any leg design other than the original, change all of the legs at the same time.
Unless you have flexibility issues, you can remove all the legs and place the bed frame directly on the floor or eliminate the bed frame altogether. If you need a higher bed but don't want to buy new legs, build a platform for your mattress and foundation.