What is the Best Way to Loosen a Rusted Screw?
Murphy’s Law states: If something can go wrong, it will. While Captain Edward A. Murphy was not referring to a rusted screw when he coined the phrase, it applies all too well. Many know the frustration of trying to get through a job that should take just a minute, but for a rusted screw that won’t budge. Unfortunately, corrosion seems to work as well as any locknut product, and if not handled correctly, a rusted screw will soon have a stripped head, leaving you in worse trouble.
Luckily, the recipe to loosen a rusted screw is a simple one. To dissolve the corrosive seal of a rusted screw, use a product such as WD-40. Spray the screw head and allow one or two minutes for the lubricant to penetrate the corrosive seal. As an alternative, you can try brushing kerosene on the rusted screw.
At this point, avoid using a power tool to remove the rusted screw. The potential to strip the head is too great. Instead, choose a screwdriver with an excellent fit for the head of the screw.
If a flathead is required, be sure the tip fills the slotted head of the rusted screw securely and is not too thin for the slot or too narrow for the screw head. A Phillips screwdriver head should likewise provide good bite into the head. In either case, there should not be play. If the tool tip shifts position within the screw’s head, it's too small. If it doesn’t fit securely into the head, it's too large.
With the correct screwdriver inserted, apply significant pressure by leaning into the rusted screw. This keeps the screwdriver from slipping and possibly stripping the head, and it also creates better bite. Attempt to loosen the rusted screw by turning it counter-clockwise. It may take a moment or two of constant torque to crack the seal and get the rusted screw moving.
If the first attempt does not work, apply more lubricant and try gently tapping the screw’s head from all angles. You might also insert your screwdriver tip and use a hammer to lightly tap downwards a few times. This can help to break the corrosive seal. Try turning the screw again.
If the head of the screw becomes stripped or damaged, or it simply won’t budge, you may need to resort to a powered screw extractor. There are several models, but in essence, these tools drill into the rusted screw itself counterclockwise, using a reverse thread. Note that some screw extractors have the potential to ruin the threads of the screw hole, requiring it to be re-tapped afterwards. Screw extractors are a last resort when manual removal has failed.
Screw extractors and lubricants are available at hardware stores everywhere. When a rusted screw is removed, it is best to replace it with a new screw, even if the rusted screw is otherwise undamaged.
Written by R. Kayne
