Loosening Old Screws

Q I have a tabletop that needs to be re-glued. Underneath is a piece of wood that is screwed in to hold the boards together. The screws are very rusted and don’t move when I try to take them out. Is there something I can use to loosen them so they can be removed?

A You can use WD-40 or Liquid Wrench to make the screws loose enough to remove. I put a couple of drops on the screw head and let it soak in. Sometimes I use a pin and make several holes around where the screw contacts the wood to help the liquid penetrate. Several applications may be necessary to loosen the rust which binds the screw to the wood. The slots in old screws are not very deep and can be stripped while trying to remove them. Use the proper size screwdriver to minimize damage. I try loosening the screw head high enough so I can use a vice grip to grab the head and remove the screw. As soon as the screw starts turning, I apply more Liquid Wrench, tightening and loosening a little to help work the chemical in.

If the slot is damaged to the point that the screw will not loosen, you can buy a screw extractor, which is a hollow tube that allows you to drill the screw out. Since this makes the hole larger, the replacement screw will have to be sized accordingly. If the wooden cleat that is on the underside of the top is original to the top, it should be refastened after the glue-up is done. An original cleat is usually made from the same wood as the table. If the table is oak and the cleat is pine or other softwood, more than likely it was added later to “repair” the top.