Have you ever had a bolt break deep within a hole – and you have no idea how to remove it?
It can be a really frustrating situation. I was thinking about how many times this happened to me in the past, and I asked myself, “what is the best way on how to remove a broken bolt?” Interestingly I used several different methods, but there is one really effective way…
The easiest way to remove a broken bolt is this: use a left handed drill bit and a self-centering shank. Drill down into the bolt in reverse. This should loosen the broken bolt. If the bolt is not freed, use an adjustable wrench to tighten a screw extractor into the bolt and reverse the bolt free.
This method is the most efficient, and we are going to talk about the most common broken bolts you’ll see:
Sheared bolt deep in aluminum
Now remember, the biggest danger here is that the surrounding material is much softer then the bolt itself – so if you’re not careful – you can damage the parent material and be unable to repair or rethread it.
With that in mind, let’s get ready to remove some bolts.
Setting Up For Success
A little prep work and the right tools go a long way…
Three things to do to make removing the bolt easier :
1. Shock the bolt using a spring-loaded punch
2. Apply heat with a small torch
3. Remember not to overheat!
4. Spray penetration – or creeping oil can help loosen the stuck bolt. The oil can be a good remover on its own!
One tool to buy right now
A hinge setting drill bit will help you drill into the bolt dead center and protect the surrounding material from damage
The reason a hinge setting bit would be helpful is this:
Notice the condition of this bolt. It has been sheered in an uneven way – if you tried to use a regular drill bit you almost guarantee the bit will slip off the uneven surface and cause damage to the parent material.
Removing The Bolt From A Small Item
Test your hinge setting attachment before actually attempting to drill the bolt.
Here we are testing for clearance – the bit fits nicely into the shaft, we make contact with the bolt and we run no risk of damaging the surround threads – making removal safe…
Load the hinge centering attachment into your cordless drill
And make sure your damaged item – (what your removing the broken bolt from) is secured as best as possible. Here we are able to use a solid bench vice to secure our workpiece.
So, you’ll want to set the drill into reverse BEFORE you start to drill into the broken bolt.
And you can see with each rotation you are removing a broken bolt.
Notice where the drill started to bite into the bolt and easily removed it from the workpiece.
Besides this being a very fast method – no threads were damaged!
Removing A Bolt From A Larger Item
Again, one of our key considerations is damaging the surrounding threading and parent material near our bolt. So here is our second method of extraction that you may prefer.
Now this is a pretty neat trick if you have access to a lathe
You can take a socket head bolt
And drill a hole through the center with the lathe
Pro-Tip: If you are very careful and use a drill bit and a vice (and have a steady hand)
You could drill through the bolt with a cordless drill and a cobalt bit.
Sometimes bolts get stuck because they are welded in place. You will need a different process to remove this type of broken bolt, but if you are looking for a entry level welder, read this review.
Now, screw in your hollowed out bolt into the workpiece as far as far as it will go. Make sure you secure the bolt down with a nut that pushed against the workpiece so it doesn’t move
And use a wrench to tighten the nut securely.
We are going to use our left handed drill bit again. The good thing about these bits is this: when the bit bites into the broken bolt, there is a good chance it will loosen the bolt and remove it without any extra effort.
Cutting paste will help reduce friction, lowering heat and help the bit to “bite”
And remember to make sure your drill is in REVERSE with the left-handed bit.
Insert the bit into the hollowed out socket bolt and gently squeeze the trigger
Once you feel the drill bit bite into the broken bolt, remove your socket head bolt, so you have access to remove the broken piece
You have now created a divot in the broken bolt – be careful now! You’re going to insert the drill into the hole without a guide
But don’t worry – find the divot you created on the bolt when you first drilled into the broken bolt.
You then slowly tap the trigger and you will bite further into the broken bolt.
The key here is low and slow – you don’t want to squeeze the trigger full bore!
You increase the chance of the drill bit slipping and damaging the surrounding threads.
Now, the bolt might be stubborn and not want to come ok – that’s ok.
Hit it with some penetrating oil and let stand for a few minutes.
After a few minutes, place your drill back into the hole and try again!
We’ve successfully drilled deep into the broken bolt, but the left-handed drill bit could not extract the broken bolt.
Use a pair of adjustable pliers to slowly turn the screw extractor into the bolt.
You may have to tap the bolt, then use the adjustable wrench to bite into the bit, then tap the extractor again. You might have to repeat this process 2 or 3 times until the extractor bites deep enough into the bolt so that you can reverse your direction and remove the broken bolt.
Removing A Deep Broken Bolt
Again, the challenge here is this: not only is our bolt buried deep in the hole, but it is also broken in an uneven way – so we have to carefully extract it.
Secure your workpiece to a bench or workstation. Here a clamp works well.
Use some penetration oil and let stand for a few minutes.
Use your socket head bolt (with the center drilled out) and tighten it down to the base of the broken bolt. Tighten with a wrench as before.
Since this bolt is a harder material, you’ll be using a cobalt drill bit, and NOT the left handed drill bit as before.
Note: you don’t want to drill deep past the bolt – you’ll hit the aluminum and damage it. So use some cutting paste and tap your drill in small bursts.
Once you feel you have reached a good depth, remove the drill and loosen the nut
With a wrench to remove the hex nut and see our progress.
You can now see the hole is started in the broken bolt
The hole is deep enough that we can use our drill with our cobalt bit too finished the job.
Tap in the screw extractor and use the adjustable wrench to bit into the broken bolt.
And out comes our broken bolt
Pro-tip: Use anti-seize grease on your bolts. Simply brush on and the bolt will move easily into the threaded slot. When you need to remove the bolt, it will slide out.
In the past, removing a broken bolt was a hassle- now you know three methods for effectively removing broken bolts! Now that you know the process you can do this easily on your own. If nothing else remember this: slow and steady with your drill gun will almost always help you remove the bold effectively.