Stripped screws are bad enough on their own, but the countersunk variety adds a whole new dimension of difficulty to this ordeal. Because these fasteners are aligned with their surroundings, you don’t have to grab anything more. This makes pliers and other common screw extraction tools unnecessary.
If a stripped countersunk screw has suddenly interrupted your repairs, don’t worry: we’ve got some nifty tips and tricks to tackle this seemingly impossible challenge.
Is the screw really stuck?
While this may sound like an attempt to enlighten you, it’s always worth double-checking if you’re using the right tool for the job. A hex driver can fit in a Torx screw head, but it will spin aimlessly inside the ill-fitting socket. A smaller Phillips screwdriver will also easily pop out of a larger Phillips screw head.
If you’re unsure of the exact type of screw you’re dealing with, check your device manufacturer’s support website for a service manual. This is the easiest way to correctly identify the type and size of screw that stands in your way.
Diamonds last forever, but screwdriver tips are consumables. They tend to wear down and become ineffective over time, so make sure your screwdriver tip isn’t worn down. This is easily apparent in a regular Phillips screwdriver, but worn hex and Torx screwdriver tips aren’t as obvious. The improved grip offered by a new screwdriver might be enough to get the screw moving.
You may want to refer to our comprehensive stripped screw removal guide, if you’re dealing with stubborn button head or socket head type fasteners. The screw heads of these fasteners protrude enough to make simple removal strategies viable.
Countersunk screws, however, warrant breaking power tools or using unusual methods that go beyond simple pliers and hand tools.
A screw extractor is a special hand tool that can handle any kind of stuck fastener you throw at it. Having a set of assorted screw extractors on hand is a good idea for covering fasteners of all sizes. Most puller sets come with a T-handle chuck to make the process easier.
Depending on the type of fastener and its degree of stripping, you may need to pre-drill the head. The diameter of the drill bit should be smaller than that of the screw shank to prevent the screw head from coming off. Use a center punch to create a divot in the screw head, if you’re worried about the bit slipping.
To extract the fastener, simply tap an appropriately sized screw extraction tool gently into the pilot hole and use the T-handle chuck to unscrew the screw. If it does not work the first time, it is advisable to enlarge the pilot hole and try again with a larger extraction bit.
Some screw extractors have left-handed bits on the opposite end. These bits cut when the drill is in reverse and form a hole that perfectly matches the attached extractor bit. A set of pullers is significantly easier to use.
2. Cut a slit in the head
If you’re dealing with a particularly mangled screw, it’s easy to save the day by cutting a whole new slot in the screw head. While hand tools such as a hacksaw will work on screw heads that protrude from the screw hole, countersunk fasteners are best handled with power tools. These include rotary cutting equipment, such as the Dremel tool.
Hardened screws are best split using abrasive cutting discs (shown above) intended for metals. However, these discs only work for large countersunk screws, where the head is large enough to accommodate the cutting tool. Otherwise, you risk damaging the area around the screw head.
Rotary tools can also be used to cut slots in smaller screw heads, but you must upgrade to a finer cutting attachment. Fine etching tips (shown below) are ideal for cutting slits in stripped fasteners too small to cut discs.
Be sure to mask sensitive circuit boards or exposed conductors to prevent metal shavings and fragments from shorting them, as discussed in our computer motherboard safety guide. Remember to wear protective glasses and clean the device with compressed air when you are finished.
3. Friction is your friend
Power tools can be overkill or dangerous for small screws. To remove these fasteners, it is often enough to give the tip of the screwdriver something substantial to grip. The humble rubber band is known to help in such cases.
Stretch a section of a rubber band and place it flat over the stripped screw head. Compliant material must fill the space between the mutilated screw socket and the screwdriver tip profile. Turn the screwdriver counter-clockwise to remove the stripped fastener.
If that doesn’t work, replacing the rubber band with a bit of steel wool or abrasive powders, like sand, can also do the trick. These materials provide enough grip to loosen larger screws that are glued more firmly.
4. Use glue to increase grip
If friction hasn’t worked for you, you might want to try something more substantial (but messier) like an adhesive. Adding a bit of superglue (cyanoacrylate or CA) to the screw head before inserting the screwdriver also does the trick. This will only work if you hold steady until the CA glue has had a chance to fuse the tool to the screw.
Tougher fasteners can benefit from hot glue’s higher adhesion and toughness. It’s safest to dab some on the screwdriver before insertion, which should minimize damage to your equipment.
5. Glue a nut on the screw head
Regular CA and hot glues just don’t cut it for stripped screws that are firmly glued into the bosses. This job is best suited to a socket wrench, which generates enough torque to unscrew virtually anything. Although a socket wrench won’t work on countersunk screws, there’s nothing stopping you from sticking a nut on the exposed screw head.
Two-component epoxy glues are the only viable adhesives capable of withstanding the enormous torque required by this company. Avoid putting epoxy glue on the rest of the equipment at all costs. Once hardened, you can use a socket wrench to apply much more torque to the glued nut on the offending screw. This method should loosen the most stubborn stripped screws.
Screw removal tips to tame all the screws
Stripped countersunk screws are a nightmare for most manufacturers, but these specialized tips should work on virtually any fastener, no matter what type or severity.
However, it’s smarter to keep screws from completely stripping by using higher quality stainless steel fasteners and upgrading your toolbox with precision machined hardened screwdriver bits. The former resists stripping, while the latter minimizes the risk of fastener stripping.
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