Removing a screw with no head, often a result of breakage or stripping, typically involves creating a new point of leverage or using specialized tools to extract the remaining shank.
Understanding the Challenge of a Headless Screw
A headless screw presents a unique challenge because the conventional method of turning it with a screwdriver is no longer possible. This situation commonly arises when a screw breaks off due to excessive torque, corrosion, or material fatigue, leaving only the threaded shaft embedded in the material. Successfully extracting it requires precision and the right approach to avoid further damage to the surrounding material or the screw itself.
Primary Extraction Method: Using a Screw Extractor
The most effective and common method for removing a headless screw involves using a screw extractor kit. These kits typically contain specialized drill bits and tapered, reverse-threaded extractors designed to grip the inside of a drilled hole and twist the screw out.
Step-by-Step Guide to Using a Screw Extractor:
- Prepare the Area: Ensure the work area is clear and stable. If the screw is in a delicate material, consider protecting the surrounding surface.
- Center Punch: Use a center punch to create a small indentation exactly in the middle of the broken screw. This will prevent the drill bit from wandering when you begin drilling.
- Drill a Pilot Hole:
- Select a drill bit that is slightly smaller than the diameter of the screw's shank. Most screw extractor kits will recommend the appropriate drill bit size for each extractor.
- Carefully drill a hole down the center of the broken screw. Drill slowly and steadily, applying consistent pressure. The goal is to create a clean, straight hole deep enough for the extractor to get a good grip.
- Insert the Screw Extractor:
- Choose a screw extractor from your kit that fits snugly into the pilot hole you've drilled.
- Gently push the screw extractor into the drilled hole.
- Use a hammer to tap the extractor down further into the hole, ensuring it bites firmly into the metal of the screw. The extractor's reverse threads will engage with the hole's walls.
- Extract the Screw:
- Attach a tap wrench, a adjustable wrench, or a drill (set to reverse/counter-clockwise) to the end of the screw extractor.
- Slowly turn the extractor counterclockwise. As you turn, the extractor's tapered, reverse threads will bite deeper into the screw, creating torque that should begin to twist the broken screw out.
- Maintain steady, firm pressure. If the screw is stubborn, you might need to apply a penetrating oil around it and let it sit for a few minutes before trying again.
Alternative Method: Gripping with Pliers
If a small portion of the screw's shank is still protruding above the surface, you might be able to use pliers as an alternative:
- Vise-Grip Pliers (Locking Pliers): These are ideal as they can lock onto the exposed shank, providing a very strong grip. Once locked on, slowly twist the pliers counterclockwise to try and unscrew the broken piece.
- Needle-Nose Pliers: For very small or delicate screws where only a tiny bit of the shank is exposed, needle-nose pliers can sometimes provide enough grip to turn it.
- Diagonal Cutters: In some cases, if the screw is soft enough and protruding, you might be able to use the cutting edge of diagonal cutters to bite into the shank and twist it out, though this can damage the cutters.
Essential Tools for Screw Extraction
Having the right tools is crucial for a successful extraction.
| Tool Category | Specific Tools | Purpose |
|---|---|---|
| Drilling | Drill (corded or cordless) | To power the drill bit for creating a pilot hole. |
| Drill bits (standard, left-hand, or specific for extractor kits) | For drilling into the center of the broken screw. A left-hand drill bit can sometimes extract the screw as it drills. | |
| Center punch | To create an indentation for accurate drilling. | |
| Extraction | Screw extractor set (often called "easy-outs") | The primary tool designed to grip and remove broken screws. |
| Tap wrench or Adjustable wrench | To turn the screw extractor. | |
| Lubricating/Penetrating oil | To loosen rusted or seized screws, making extraction easier. | |
| Gripping (Optional) | Vise-Grip pliers, Needle-nose pliers, Slip-joint pliers, Locking pliers | For gripping and twisting if part of the screw shank is exposed. |
| Safety | Safety glasses, Gloves | Essential for protecting eyes from debris and hands from sharp edges or tools. |
Tips for Successful Extraction
- Patience is Key: Do not rush the process. Applying too much force too quickly can cause the extractor to break, compounding the problem.
- Lubrication: For stubborn or rusted screws, apply a penetrating oil and let it soak for 15-30 minutes, or even overnight, to help loosen the threads.
- Reverse Drill: If your drill has a reverse setting, you can use it to turn the screw extractor counterclockwise. However, proceed with caution and use a slow speed to maintain control.
- Heat: In extreme cases, applying a small amount of heat (using a heat gun or soldering iron, carefully) to the material around the screw can cause it to expand slightly, potentially loosening the screw. Be extremely careful not to damage the surrounding material.
By following these methods, you can effectively remove most headless screws, preserving the material they were embedded in.
