How To Extract a Screw
Sawtooth edges make these small tools very handy to have around the shop. Use a drill press, if possible, to bore a clean hole around the screw. Or, a hand-held drill with a guide block works fine for screws located outside of the reach of a drill press. Once the screw is out, patch the hole with a length of dowel or a matching plug.
– For screw sizes #4 – #8, use a 1/4″ tube
– For screw sizes #4 – #10, use a 5/16″ tube
– For screw sizes #10 – #12, use a 3/8″ tube
– If the screw shank is fully above the surface, simply grab the shank with needle-nose pliers
and twist the broken screw out.
– If the area won’t be visible when finished or the shank is flush with the surface, excavate around the shank, then use pliers to extract the screw.
– Stubborn screws may loosen with heat applied directly to the screw with a soldering iron.
Use a cut-off wheel on a rotary tool to cut a slot into the top of the broken screw. Then, use a slot-head screwdriver to reverse the screw’s shaft out of the hole.
Tips to Avoid Breaking Screws
– Use a better quality screw.
– Drill properly sized pilot holes, which are different for hardwood and softwood (see chart at below).
– Lubricate the screw with wax or paraffin. Grease or oil may leach into the wood causing finish problems.
– Always clamp the workpiece to your bench or in a vise to hold the piece securely.
– For brass screws, first install a steel screw of equal size to thread the hole, then replace that screw with the brass screw.
Proper Sizes for Pilot Holes
– Tom Nunlist; Illustrations by Matt Bantly