Stripping a screw means damaging it to the point where your screwdriver or drill bit can no longer grip it and make it turn. The tool just spins freely in the screw head without catching. This is one of the most common frustrations in DIY work, and it happens in two distinct ways that require different fixes.
Two Types of Stripping
When most people say they’ve “stripped a screw,” they’re talking about the screw head. The small slots or recesses where the screwdriver bit sits get rounded out and smoothed over, so there’s nothing left for the bit to grab onto. You can usually see this clearly: the sharp edges inside the drive pattern are worn down or chewed up, and the bit just spins when you try to turn it.
The second type is stripped threads. Threads are the spiral ridges that wrap around the screw’s shaft and grip into the material. When threads strip, the screw turns but never tightens. It just keeps spinning in place. This happens when the grooves in the surrounding material (wood, metal, or plastic) get torn out, usually from overtightening or from using a screw that’s too large for the hole. In metal-to-metal connections, the threads inside the receiving hole can also shear off if a bolt is forced in at an angle or cranked too hard.
Both problems leave you with a fastener that won’t do its job, but the causes and solutions are quite different.
Why Screw Heads Strip
The most common cause is using too much speed and too much force with a power drill. When the bit starts to slip out of the screw head (a problem called “cam-out”), it grinds away the edges of the drive recess with each rotation. Within seconds, the damage is done.
Other common causes include:
- Wrong size bit. A bit that’s slightly too small for the screw head won’t seat fully, concentrating force on the edges instead of distributing it across the full drive pattern.
- Worn bits. Screwdriver bits wear down over time. A rounded bit transfers less torque and is far more likely to slip.
- Angled driving. If your drill or screwdriver isn’t aligned straight with the screw, the bit only contacts part of the recess, which dramatically increases the chance of cam-out.
- Soft screw material. Brass and aluminum screws are significantly softer than steel. On standard hardness scales, copper alloys and aluminum fall into much lower categories than steel or iron. That means their drive recesses deform more easily under the same amount of force.
Why Threads Strip
Thread stripping is a different problem. It happens in the material the screw is biting into, not in the screw head itself. The most frequent cause is overtightening. Once the screw is fully seated and you keep cranking, the threads tear through the surrounding wood or plastic, carving out the hole until there’s nothing left to grip.
Driving a screw without a pilot hole, especially in hardwood or near the edge of a board, also increases the risk. The screw forces the wood fibers apart under tremendous pressure, and if the wood splits or crumbles, the threads lose their hold. In metal applications, cross-threading (starting the screw at an angle) can shear the internal threads off entirely, leaving a smooth, useless hole.
How Screw Drive Design Affects Stripping
Not all screw heads are equally prone to stripping. The classic Phillips head, with its cross-shaped recess, was actually designed to cam out at a certain torque level. That was useful in factory assembly lines decades ago, but it makes Phillips screws more vulnerable to stripping during everyday use.
Robertson (square drive) screws offer better grip because the bit seats deeper and the flat walls resist cam-out. Torx (star-shaped) screws take this further, with six contact points that distribute force more evenly. Experienced builders often prefer Torx for this reason. With a Torx screw and a good-quality bit, you’re more likely to snap the bit than strip the screw head. The quality of both the screw and the bit matters, though. Cheap fasteners with shallow recesses will strip regardless of design.
How to Remove a Stripped Screw
If the head is stripped but the screw still needs to come out, you have several options depending on how badly it’s damaged.
For lightly stripped heads, the simplest trick is to place a wide rubber band flat over the screw head, then press your screwdriver or drill bit firmly into it and turn slowly. The rubber fills the gaps in the damaged recess and adds enough friction for the bit to catch. This works surprisingly well on screws that are only partially rounded out. Keep the speed low and apply steady downward pressure.
If the screw is both stripped and rusted or seized, spray it with a penetrating lubricant and let it soak for at least an hour (or longer for badly corroded fasteners). Then try the rubber band method. For seriously corroded screws, applying the lubricant multiple times over several days can help break down the corrosion bond before you attempt removal.
For more severe stripping, a screw extractor is the standard tool. These are reverse-threaded bits that dig into the damaged screw head as you turn counterclockwise, gripping tighter the more you turn. You typically drill a small hole into the center of the stripped screw first, then insert the extractor. They’re sold at any hardware store and work on most small to medium screws.
Other approaches include cutting a new slot across the screw head with a rotary tool, then using a flathead screwdriver. Or, if the screw head is raised above the surface, locking onto it with pliers or a pair of locking grips and turning it out manually.
How to Fix Stripped Threads
When the threads in the hole are gone, the screw has nothing to bite into. In wood, the classic fix is to fill the hole. Remove the screw, pack the hole with wooden toothpicks or matchsticks dipped in wood glue, let it dry, then drive the screw back in. The new wood gives the threads fresh material to grip.
For a stronger repair, drill out the damaged hole completely, glue in a wooden dowel, and drill a new pilot hole once the glue has cured. In metal, stripped threads can be repaired with a thread insert, which is a small coil that restores the original thread size inside an enlarged hole.
If neither repair is practical, you can sometimes move to the next screw size up. A slightly wider screw will reach fresh material beyond the damaged threads.
Preventing Stripped Screws
Most stripping is avoidable with a few habits. Drill a pilot hole before driving screws into hardwood, dense softwood, or near the edge of any board. The pilot hole should closely match the screw’s inner shank diameter so the threads still have plenty of material to grip, but the wood isn’t under so much pressure that it cracks.
Use the right size bit. It should fit snugly into the screw’s drive recess with no wobble. Replace bits when they start to look rounded. Keep your drill or screwdriver aligned straight with the screw, and reduce the speed on your drill, especially as the screw gets close to fully seated. High speed with a power drill is the single easiest way to strip a head.
If your drill has a clutch setting (the numbered dial near the chuck), set it to a lower number. The clutch disengages the motor when the screw reaches a certain resistance, which prevents overtightening and protects both the head and the threads. For screws going into softwood or drywall, this one adjustment eliminates most stripping.
When working with soft metals like brass or aluminum, hand-drive the last few turns instead of relying on a power tool. These materials have very little margin for error, and a moment of inattention with a drill can round out the head instantly.