Wood Screws Won’t Tighten

Problem: Screws in hinges, furniture, or moveable fittings work loose and won’t stay tightened.

Background: Wood screws come in a wide variety of sizes and head types, including flat head, round head, and oval head, and may be slotted or Phillips type. They are threaded about two-thirds of their length. The Phillips heads work better with a drill or power screwdriver unit. Common screws will range in diameter thickness from No. 2 (small) to No. 16 (large), and in length from about ¼ inch to 2¼ inches. Generally screws are sized so that two-thirds will go into the base material, or second member, to which the surface piece is being fastened. It is a simple matter to tighten loose screws, but if the threads do not hold, extra work is necessary.

 

What to do: If the threads are worn out, or the screw has become loose in its original hole, try using a larger screw. In some cases this may not be possible, because the holes in the metal fittings or the thickness of the wood will not allow it. The options are to fill the screw hole with a wood plug, plastic wood, or steel wool. Even toothpicks or wooden safety matches with the heads broken off can work. Fill the hole with glue be fore inserting tapered wood plugs, toothpicks, or match stems. Once the glue has set, trim the wood material off flush with wood. Predrill a hole slightly smaller than the screw size when either wood plugs or plastic wood are to be used. With steel wool, insert a small amount into the screw hole and then reinsert the screw.

Special advice: Paraffin or wax can be used to lubricate screws for easier turning. (Do not use soap because it can cause the screw to rust.) Also don’t hammer in screws part way; it’s best to use a starter hole or, even better, to use a drilled pilot and shank holes. Many woodworking books have charts showing the drill bit sizes to use for pilot and clearance holes.

Helpful hint: You can buy special drill bits at home centers and hard ware stores which drill the pilot hole, clearance hole, and counter sink all in one operation. These are helpful if you need to drill many holes.