How to Remove a Stripped Bolt: 10 Proven Fixes

Few things stall a repair like a bolt that won’t turn. The wrench slips, the head rounds off, or the fastener just sits there rusted solid while your knuckles pay the price.

Before you reach for a drill, know there is almost always a gentler way out. The trick is matching the method to the problem. A rounded head needs fresh grip, a rusted-in bolt needs its corrosion seal broken, and a bolt sheared off flush needs to be cut or drilled.

This guide walks through 10 proven methods to remove a stripped bolt, starting with quick hand-tool fixes and building up to heat, extraction, and welding. Work down the list and most bolts give up long before the last resort.

Key Takeaways

Restore grip first: A wide rubber band packed between the wrench and a lightly rounded head, or a bolt extractor socket for a badly rounded one, often turns it with no cutting.
Break the rust seal: Shock the head with a punch and hammer, or heat the metal around the bolt with a torch so the hole expands away from the threads.
Make a new drive surface: Cut a slot across the head with a rotary tool and turn it with a large flathead, or weld a nut onto a flush or rounded head.
Save drilling for last: Center-punch the bolt and run a left-handed cobalt bit, whose reverse cutting action often spins the bolt out on its own.

How to Remove a Stripped Bolt

The right method depends on how badly the bolt is stripped and where it is located. We will start with the least invasive techniques and work our way up to the “nuclear options.”

Method #1: Impact Force

Before you get fancy, try brute force. Rust acts like a glue, and a sharp, sudden shock can shatter that bond. This is often all you need to get things moving.

Here is how to shock it free:

Manual shock: Take a flat punch or a chisel and place it on the center of the bolt head. Strike it firmly with a hammer several times.
Impact driver: If you have an impact driver (not just a drill), use it. The rapid percussive hammering is designed specifically for this scenario.

Take Note

This method works best on bolts with mild corrosion. If the bolt head is completely rounded off, you may need to combine this with cutting a slot (Method #3).

Method #2: Heat

Physics is on your side here. When metal gets hot it expands, and when it cools it contracts. Rapidly changing that temperature can break the corrosion seal holding the bolt in place.

The torch is the riskiest tool on this list. NFPA research counted an average of 3,396 structure fires a year started by hot work between 2017 and 2021 ⁽¹⁾, so clear rags and fuel out of the way, keep an extinguisher within reach, and let any penetrant you already sprayed dry off before you light up.

You have two main approaches for using heat:

Heat the Bolt

Use a propane or MAP gas torch to heat the bolt head directly. Get it hot enough to expand (but be careful near plastic or painted parts). Let it cool slightly, then hit it with a penetrant like WD-40 or Kroil. The cooling metal will suck the oil deep into the threads.

If standard penetrating oil doesn’t work, try CRC Freeze-Off. It freezes the bolt instantly to crack the rust while delivering a lubricant.

Heat the Housing

Sometimes it is better to heat the metal surrounding the bolt. This expands the hole, effectively making it larger than the bolt itself. While the metal is expanded, try to turn the bolt. This is particularly effective on aluminum housings with steel bolts.

Method #3: Relief Cuts (The Slot Method)

If the wrench keeps slipping because the head is rounded, you need to create a new way to grip it. This is where a rotary tool (like a Dremel) or a hacksaw comes in handy.

Cut a deep, straight slot across the top of the bolt head. You have now effectively turned your rounded bolt into a large flathead screw. Use the largest flathead screwdriver you have to turn it out.

For extra torque, you can use a chisel in the slot and tap it counterclockwise with a hammer to get it started.

Method #4: Restore Grip (Rubber Band, Smaller Socket, Extractor Sockets)

Before you buy a special tool, try the cheapest fix first. Wedge a wide, flat rubber band between the socket or wrench and the bolt head. The rubber conforms to the rounded surface and can give just enough grip to break a lightly stripped bolt loose. For a hex head that is more chewed up, hammer a six-point socket one size smaller than the head onto it. The sharp interior corners bite into the soft metal and restore a solid grip for a breaker bar.

When those come up short, a dedicated set of bolt extraction sockets is worth owning if you do much car work or DIY. They are the go-to for badly rounded heads.

These sockets have spiraled flutes inside that dig into the metal of the bolt head. As you turn your ratchet counterclockwise to loosen the bolt, the socket bites down harder. The more force you apply, the tighter it grips.

Simply hammer the extractor socket onto the rounded bolt head, attach your ratchet, and turn. This is often the most reliable method before you have to start drilling.

Method #5: Rocking the Bolt

If you can get a grip on the bolt but it only moves a tiny bit, do not force it all at once. You risk snapping the head off completely.

Instead, work the bolt back and forth. Tighten it slightly, then loosen it. Repeat this process, moving it a little further each time. This “rocking” motion helps clear the rust and debris from the threads.

Generously apply penetrating fluid during this process. The back-and-forth motion helps work the oil down into the threads where it is needed most. A product labeled penetrating oil, like PB Blaster or Kroil, works far better here than plain WD-40. A Machinist’s Workshop bench test on deliberately rusted fasteners found a dry nut took roughly twice the breakaway torque of one treated with WD-40, about five times a nut treated with Kroil, and close to ten times a nut treated with a homemade 50/50 mix of automatic transmission fluid and acetone, which wicks in fast because acetone is so thin while the fluid lubricates.

Method #6: Drill It Out

Last Resort

Drilling should be your backup plan. It is slow, risky, and if you damage the housing threads, you will have a much bigger repair job on your hands.

If the head has snapped off flush with the surface, drilling is your only option.

Put safety glasses on before the bit touches metal. NIOSH estimates that about 2,000 US workers a day need medical treatment for a job-related eye injury, most of them caused by small particles striking the eye ⁽²⁾.

Here is the safest way to do it:

Center punch: Mark the exact center of the bolt with a center punch. This prevents your drill bit from wandering and damaging the threads.
Left-handed bits: Use a left-handed drill bit. This is a pro tip. As the drill spins counterclockwise to cut, the torque and heat often catch the bolt and spin it right out.
Start small: Begin with a small pilot hole, then step up to larger bits until you are close to the thread walls.
Pick it out: Once the bolt shell is thin enough, you can often pick the remaining metal out with pliers or a scribe.

Method #7: Spiral Screw Extractor

This works in tandem with drilling. A spiral extractor (often called an “easy-out”) is a tapered, reverse-threaded bit designed to jam into a hollowed-out bolt.

Drill a pilot hole into the center of the stuck bolt. Tap the extractor into the hole with a hammer. Attach a handle or wrench to the extractor and turn it counterclockwise.

Because the extractor is reverse-threaded, it pulls itself deeper into the hole as you turn, eventually transferring enough torque to back the bolt out. Warning: These extractors are hard but brittle. If you snap one off inside the bolt, it is incredibly difficult to drill out.

Method #8: Pipe Wrench

For larger bolts or studs where the head is rounded but still accessible, a pipe wrench is a classic solution.

Pipe wrenches have self-tightening teeth. As you pull on the handle, the jaws clamp down harder. Position the wrench on the bolt head or exposed stud and pull. The teeth will dig into the metal, creating a high-friction grip that standard wrenches can’t match.

Method #9: Weld a Nut

This is the “magical” fix if you have access to a welder. It works on bolts that are broken off flush or completely rounded.

Find a nut that is roughly the same diameter as the bolt. Place it over the bolt head (or the flush surface). Use a MIG welder to fill the inside of the nut, welding it firmly to the stuck bolt.

This accomplishes two things:

It gives you a brand new, clean hex head to put a wrench on.
The intense heat from the welding process travels down the bolt, expanding it and breaking the rust bond almost instantly.

Method #10: Air Hammer/Chisel

If you have an air compressor, an air hammer with a chisel bit can vibrate a stubborn bolt loose.

Place the chisel edge against the outer rim of the bolt head (or a notch you cut into it). Pull the trigger and apply pressure in the counterclockwise direction. The vibration alone is often enough to shatter the rust, while the chisel drives the bolt around.

This requires a steady hand, so be careful not to slip and gouge the surrounding surface.

FAQs

Why Do Bolt Threads Strip?

Bolt threads strip most often from overtightening, cross-threading (starting the bolt at an angle), or using the wrong size fastener, all of which shear or flatten the thread ridges. Corrosion adds to the problem by eating away the metal over time, so the weakened threads can crumble the moment you put a wrench on the bolt.

Can You Fix Stripped Threads on a Bolt?

Sometimes, depending on how bad the damage is. If the threads on the bolt shank are only lightly flattened, running a thread die down the shank can reshape them enough to reuse it. If the threads are sheared off or badly corroded, replace the bolt. Stripped threads inside a hole are a different repair, fixed with a thread insert like a Heli-Coil rather than a die.

Does WD-40 Help Remove Stripped Bolts?

Not as much as a true penetrant. Standard WD-40 is mainly a water displacer. In a Machinist’s Workshop bench test it roughly halved the torque needed to free a rusted fastener, while a dedicated penetrant like Kroil or a 50/50 ATF and acetone mix cut it by four to ten times. Reach for a product labeled penetrating oil, such as PB Blaster or WD-40 Specialist Penetrant, and give it several minutes to soak in.

What Are the Best Drill Bits for Drilling Out Bolts?

Cobalt drill bits are the best choice for hardened steel bolts because they shed heat well and stay sharp longer in hardened steel. For the best odds, use left-handed cobalt bits. They spin counterclockwise, so the bit often grabs the loosened bolt and backs it out before you finish drilling.

What Is the Best Tool to Remove a Stripped Bolt?

It depends on the damage. For a rounded but intact head, a bolt extractor socket such as the Irwin Bolt-Grip is the best non-destructive tool. For a bolt sheared off flush, welding a nut onto the stub is the most reliable professional fix, with left-handed cobalt bits and a spiral screw extractor as the backups.

How Do You Remove a Rounded Bolt Without an Extractor?

Start by filling the gap between your wrench and the head. A flat, wide rubber band pressed into the rounded head, or a six-point socket one size smaller hammered on, restores enough grip for many bolts. If that fails, cut a straight slot across the head with a rotary tool and turn it with a large flathead screwdriver, or clamp an exposed head with a pipe wrench, whose teeth dig in harder as you pull.

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