What is a Stripped Screw?
A stripped screw drive is a common issue in fastener installation, and knowing how to remove a stripped screw is a vital skill for any engineer. Stripping occurs when the screw drive becomes so damaged that a driver no longer engages properly with the screw, causing a screwdriver or drill to slip and rotate within the drive, rather than drive the screw. Stripping commonly occurs due to improper installation or poor-quality tooling, but may also occur as an unavoidable result of heavy use if a screw is regularly reused. Stripping is also slightly more common in stainless steel screws, which are more vulnerable to damage due to the fact that they cannot be hardened to the same level as high tensile steel alternatives.
Shallow drive types such as the Philips and Pozi drive are particularly prone to cam-out and slippage, which can cause damage to a screw drive, particularly if the fastener is regularly removed and reinstalled. One way to avoid stripped screws is to use a socket drive. A Torx drive is specifically designed to maximise torque, while also being highly resistant to stripping. For more information on cam-out, and how drive types have evolved over the last 200 years, read our article, What is The Best Screw Drive?
Stripped screws are particularly common on laptops and other electronic devices, where thread-locking compounds are used to improve vibration resistance of fasteners. Thread-locking solutions make screws more resistant to loosening, which can cause slipping and stripping if the screws are difficult to remove. This article may be particularly useful for those looking to remove a stripped screw from a laptop.
Items You May Need:
- An electric drill
- A range of screwdriver or drive bit sizes
- Rubber bands
- Duct tape
- Low-strength glue
- A torque limiting screwdriver
- A screw extractor kit
- A hack saw or dremel
- A claw hammer
How Can a Stripped Screw Be Removed?
Removing a stripped screw can be done in one of two ways, by increasing friction, or increasing torque. The key factor in removing any screw, stripped or not, is torque. Torque is required to disengage a tightened screw’s thread from its surroundings, and increasing friction improves torque transmission between the driver and the screw.
Increasing friction is possibly the simplest way to remove a stripped screw, and essentially boils down to improving the gripping ability of the existing screw drive in a (preferably) non-destructive way. Friction can be increased in several ways:
Ensure the Correct Screwdriver Size.
Using the wrong size or type of screwdriver is one of the most common causes of screw stripping. A properly sized screwdriver will increase engagement, increasing friction and allowing greater torque to be transmitted.
Use an Additive For Grip.
Adding another item or material between the screw and the driver can often provide all the extra grip necessary to loosen a stripped screw. Many options exist for improving grip:
- Rubber bands - a thin, wide rubber band.
- Duct tape - a strip of duct tape with the adhesive side facing into the screw drive.
- Glue - a low-strength glue can increase friction without leaving any long-term residue.
How to Remove a Stripped Screw with a Rubber Band
A stripped screw can often be easily removed with a rubber band. The band is placed between the drive and the screwdriver to increase friction and engagement. When using this method, special care must be taken to choose a rubber band which is adequately flat and wide. A rubber band which is too thick, too wide, or too thin may not function optimally.
Torque can be increased primarily by using higher quality tooling. A more powerful drill, or a screwdriver with a more substantial handle, will provide greater mechanical advantage, and will allow more torque to be exerted.
Sufficient torque is the primary requirement for loosening a screw, meaning that (in theory) increasing torque will aid in removing a stripped screw. The potential downside of increasing torque is that increasing torque without improving driver engagement can potentially cause the driver to continue slipping, simply causing further damage to the drive of the screw.
Use Alternative Tooling
Torque Limiting Screwdriver
While not a solution for a pre-stripped screw, a torque limiting screwdriver will prevent stripping by only allowing a set amount of torque to be exerted during installation. By limiting torque to an acceptable level, torque limiting screwdrivers prevent screws from being stripped in the first place.
If the stripped screw in question has an exposed head, a resolution may be as simple as using pliers to remove the screw. Of course, it should be considered that using pliers on a round head will not provide the friction required to remove tightly fastened screws, and the use of pliers may cause cosmetic damage to the outside of the screw head.
One method to remove a stripped screw is to use tooling for the removal of stripped screws. Use of a screw extractor involves the modification of the screw drive to accommodate a special driver, which is reverse-threaded to tighten as the screw is driven in reverse. This type of tooling is available as a manual tool or as a drill bit, and is usually highly effective. The downside of screw extractors is that they permanently alter the drive of the screw, making reinstallation impossible.
Create a New Drive
Cut a Notch For a Flat-Head Screwdriver.
If a drive for a screw is so irreparably damaged that a replacement drive must be created, by far the simplest drive to create is a simple slotted drive. If the head of the screw is accessible, a slot for use with a slotted screwdriver can be created using a hacksaw or dremel.
Attach a Nut With Epoxy.
A fastener drive can also be converted using a spare nut and a strong epoxy adhesive. Attaching a hexagon nut to the head of a screw essentially creates a makeshift hexagon bolt. This can be done by attaching an oversized flat hexagon nut around the head, or placing a smaller nut directly on top of the old drive. Using the latter method, special care should be taken to keep the nut aligned with the core of the screw.
If All Else Fails...
As a last resort, several destructive methods are available for removing a stripped screw. All of the below methods may cause unwanted damage to screws and housings:
Drilling Out the Screw
A stripped screw can usually be drilled out using a an oversized drill bit. Drilling out an unwanted screw wIll increase the size of the original hole, meaning that a different screw size must be used if the hole is reused.
Use Professional Spark Erosion
Spark erosion, or EDM (electrical discharge machining), can be used to essentially burn the screw out of its hole with an intense electrical field. Spark erosion should only be performed by a trained professional. Spark erosion is particularly useful in with extremely hard metals which cannot be damaged by more traditional tooling.
Use A Claw Hammer
By far the most primitive and destructive of the solutions in this article. If no other solution is available, and the housing material is soft enough, the ‘claw’ of a claw hammer can be used to treat a stripped screw like a stubborn nail. This method is almost guaranteed to cause unsightly damage.
How to Remove a Stripped Screw From a Laptop
As previously mentioned, laptop computers can be particularly vulnerable to stripped screws due to the thread-locking solutions often used in their construction. When performing these steps on a laptop, it is often best to avoid the most destructive methods to avoid causing damage to an expensive computer. Increasing the friction between driver and drive is almost certainly the most ideal solution for removing stripped laptop screws.
How to Remove a Stripped Screw From Plastic
Special care must be taken when attempting to remove a stripped screw from soft materials such as plastic, particularly if the fastener itself is manufactured from plastic. Due to the difference in hardness between plastic fasteners and drive bits, (which are often made from metal) plastic screws can be prone to rounding if adequate precautions aren't taken. The use of a rubber band is the best solution here, as the rubber will serve to protect the plastic screw from further damage.
A stripped screw can be removed in a variety of ways, from the basic and unintrusive, to the extreme and destructive. It is sometimes difficult to identify the best method for how to remove a tripped screw, but the best solution to avoid unnecessary damage is to start simple and escalate as necessary - most stripped screws can be removed with relatively minor modifications, with no need for some of the more severe solutions within this article. In most cases, there is no need to hire a specialist in spark erosion when duct tape will do.