Stripped bolts, rounded heads, and rusted hardware are a real pain. Getting a stripped bolt free of its housing can be a challenge. It is one of the things mechanics and DIY enthusiasts dread the most.
But there is a way to remove stripped bolts without having to stick a dollar in the swear jar every time. We show you how.
Simple Ways to Unscrew a Stripped Bolt
A chisel, a hammer drill and heat, as well as lubricant oil will work most of the time. Heat expands and contracts the bolt, breaking the corrosive seal. Using the hammer drill adds impact as well as torque to remove the bolt. Hitting a chisel with a hammer can sometimes shock the bolt free.
How to Remove a Stripped Bolt
Whether you’re looking for a super easy way or open to taking a longer route, there’s a method for you. Let’s start with the most basic method:
Method #1: Impact Force
Brute force is the easiest way to remove that rusted bolt. So before you attempt the other methods, try this first.
Take a chisel or a punch and a hammer, and strike it in the center of the bolt. Your aim is to shock the bolt free with the impact. If it doesn’t work the first time, you can try it as many times as you feel appropriate.
Before you concede defeat, try forward and reverse force using an impact gun. The action of sudden opposing motions should work to free the bolt.
We chose it as the first method because it is the one technique that requires limited knowledge of specialist tools and can be grasped by almost anyone.
Method #2: Heat
Heating the bolt expands the metal, and then when it cools, it retracts. This process breaks the corrosive seal of the bolt in the housing.
There are two effective ways to do this:
Heat the Bolt
Take a blow torch and heat the bolt directly. Make sure it is almost red hot so that it expands. Then let the hardware cool. Next, use some penetrants like WD-40 or Kroil penetrating oil to help dislodge the bolt from its housing.
If that fails, try CRC-Freeze Off. To add extra force, you can resume the impact method with the impact gun, using forward and reverse motion.
Heat the Housing
Sometimes, heating the bolt’s housing works better. It works in the same way as the first method, by heating the metal so that it expands and retracts. This, in turn, breaks the seal and allows the bolt to be removed.
Again, try using penetrating oil to soak into any gaps that may have appeared in the expanding and retracting cycle. This helps to lubricate the bolt, making it easier to free with an impact gun.
Method #2: Relief Cuts
Relief cutting is the most failsafe way of removing either rusted bolts or nuts that are stuck fast. What you do is cut two or three grooves with a hacksaw or rotary cutting tool into the head of the bolt. Cut them almost as deep as the thread.
Then place a chisel in the groove and hit it with a hammer. You want either the bolt to turn in the housing, causing the minimum of damage or the nut to split right off the bolt.
Also, by using this method, you should be able to get enough grip on the bolt or nut to clamp on some locking jaw pliers. You can then twist the bolt out of the housing.
Method #3: Shake the Bolt
This, like the impact method, is one of the easiest. Grab a socket wrench and start twisting the bolt or nut backward and forward, trying to loosen it further each time.
Feel for the bolt to offer some resistance, and initially, always move the same distance forward as backward, returning the bolt to its original position. Gradually increase the rotation with each turn until you see the bolt start to rise out of the housing.
Grab some penetrating oil and squirt it into the gap you have created between the bolt and the housing. This lubricates the hidden thread and allows for a cleaner exit of the bolt. Hopefully, there will also be less damage to the threads in the housing.
You will need patience when using this method, but it almost always works.
Method #4: Drill it Out
Also, be aware that you could break apart the bolt and leave fragments of metal inside the hole.
However, this is the go-to method if the bolt has sheared off and is flush with the surface of the material.
You start in much the same way you would drilling out a lock.
Start with a smaller drill bit, working through the center of the sheared bolt lengthways. As the bit works its way down the shaft of the bolt, it heats it, and the same principles of using heat to loosen the bolt apply.
The bolt also has room to contract when it cools, because the shaft is now hollow. If you are lucky, a pair of long-nosed pliers will be sufficient to grip the bolt and twist it out. If not, you will have to scale up the size of the drill bit and work through the frozen bolt once more.
Hopefully, the hardware will break apart, and you can clean the hole free of debris. Be careful not to damage the thread. But if you do need to make repairs; use a universal tap tool.
Method #5: Bolt or Screw Extractor
This method is a little trickier to get right. Get it wrong, and you could be causing a more significant problem than the one you were supposed to solve.
Start by drilling a small pilot hole into the shaft of the bolt or screw. Don’t drill the entire length as this will weaken the integrity of the frozen hardware and also reduce the grip of the extractor.
Then, insert the extractor bit into the pilot hole, giving it a couple of taps with the hammer. Turn the T-bar or locking pliers in a counterclockwise rotation, applying downward pressure. At this point, the screw or bolt should twist out.
Be careful not to snap the extractor bit inside the hollowed hardware. If you do, you are going to have a devil of a job getting that bolt out of the hole. It may also require a specialist drill bit.
Method #6: Pipe Wrench
Everyone owns a pipe wrench, right? This method is one of the most basic ways to extract a stripped bolt. It won’t work on a rusted screw because the screw sits flush with the surface of the material.
Fix the head of the pipe wrench over the head of the bolt and tighten it down. As you twist, the wrench bites down on the bolt head and grips harder. If the hardware is stubborn and won’t move, try the “shake it” technique, by rocking the screw back and forth, increasing the rotation with each turn.
Method #7: Weld a Bolt
This method requires some knowledge of welding and specialist equipment, so it might not be an option for everyone. Sometimes the bolt head or nut is so stripped it can’t be turned, even by locking jaw pliers. To rectify this, take a nut and bolt head of slightly larger size and tack-weld it to the body of the bolt.
Fill the nut with weld as well as running a bead of the weld where the two parts meet. This welding process has the added benefit of heating the bolt to loosen the rusted grip in the housing. It also allows you to use a socket on the bolt.
Method #8: Air Hammer/Chisel
This method is similar to the impact procedure in that the air hammer and chisel apply downward force on the stripped hardware to shock it free of the rusted aperture. This method, like others, has limited success and works better on screws and bolts that are more exposed.
Method #9: Screwdriver
A screwdriver is particularly effective when removing rusted screws, especially Philips or cross-head screws.
You can use this method on stripped bolts as well. However, the force needed to rotate the hardware free from the corrosive seal would be extremely high, so it has a limited effect.
Cross-head screws can take a lot of torque, but when they rust, they become brittle and strip easily.
There are two ways to use a screwdriver to loosen bolts and screws:
Take a Philips screwdriver and place it in the head of the screw. Make sure that it is the correct size because you are looking for a tight fit. You don’t want any wiggle room, as this will strip the head of the screw.
Now take a hammer and strike the screwdriver two or three times. The impact cuts into the softer screw head, increasing the grip of the screwdriver. Now try and turn the screw counterclockwise. If the screw moves, turn it backwards then forwards, much like shaking the bolt.
This rocking motion should be enough to get the screw out.
Cut a New Groove
Has the screw head completely rounded off and is sitting proud of the material? Grab a hacksaw or rotary cutting tool and cut a new groove into the head of the screw.
A rotary tool works well if the screw is flush to the surface. Then take a flat blade screwdriver and insert it into the slot. Use the hammer to whack the screwdriver down, and then start to turn the screw.
Method #10: Reinstall New Bolts or Nuts
If all else fails, and you’ve tried all the methods we have listed, you might have to accept that you aren’t going to remove that stripped bolt. It may be time to install a new one.
First, check that you can install new bolts. Some precision engineered components, especially in machinery, have things in specific places for a reason. If you find that it is possible to install a new bolt, you are going to need some specialist tools.
What you will need:
- Various sizes of HSS drill bits.
- New bolts or nuts.
- A tapping tool.
- Can of compressed air.
1. Drill the Pilot Hole
In this instance, we will assume the material is metal. Using a drill bit for metal, make a pilot hole in the material. The most important thing is to make sure the hole is entirely straight, so be sure to hold the drill perpendicular to the hole. Once you have reached the desired depth, remove the drill bit.
2. Use a Larger Drill Bit
Enlarge the hole using a more significant size drill bit. Make sure it has a slightly narrower diameter than the tapping tool so that it has enough metal to gain purchase. Remove the drill bit and clean out the hole with a can of compressed air.
3. Use the Tapping Tool
Insert the end of the tapping tool into the hole. Keep the tapping tool perfectly straight because otherwise the bolt will be off-center, and while it will still hold, it will look untidy. Using the T-bar, gently twist the tapping tool and let it feed down into the hole.
When you reach the bottom, go counterclockwise, and remove the tapping tool. You are now ready to insert the new bolt.
Bolt for Freedom
As we’ve demonstrated, knowing how to remove a stripped bolt is possible. You can use most of the methods simultaneously, as they are not mutually exclusive. What it proves is that a perceived hard task is easier to execute than you might think.
If we could sum up the procedure for removing a stripped bolt most simply, we might say: hit it, heat it, and hand-crank it.