How To Remove Broken Bolt

Do you have a broken bolt that you’re struggling to remove? Don’t worry, you’re not alone. Broken bolts are a common problem, but they can be frustrating to deal with. However, there are a few simple steps you can follow to remove a broken bolt without damaging the surrounding area. In this article, we’ll walk you through the process of removing a broken bolt, step-by-step.

First, you’ll need to gather a few tools. You’ll need a drill, a drill bit, a bolt extractor, and a wrench. Once you have your tools, you can begin the process of removing the broken bolt. Start by drilling a small hole into the center of the broken bolt. Be careful not to drill too deep, or you could damage the surrounding area. Next, insert the bolt extractor into the hole and turn it counterclockwise. The bolt extractor should grip the broken bolt and remove it from the hole.

Using Reverse Drill Bits

Reverse drill bits, also known as left-handed or extractor bits, are specifically designed to remove broken bolts. They are tapered on the opposite side of a standard drill bit, which allows them to bite into the damaged bolt and loosen it without further damaging the threads.

Selecting the Correct Bit Size

It’s crucial to choose the appropriate bit size for the broken bolt. The bit should be slightly smaller in diameter than the bolt itself. Refer to the table below for recommended bit sizes based on bolt diameters:

Bolt Diameter (mm)	Bit Diameter (mm)
4	3.5
6	5.0
8	6.5
10	8.0
12	10.0

Step-by-Step Instructions

Once you have the appropriate bit size, follow these steps to remove the broken bolt:

Start Drilling Slowly: Position the reverse drill bit over the broken bolt and start drilling slowly. Apply light pressure to avoid damaging the workpiece.
Reverse the Drill When the Bit Bites: As the bit bites into the bolt, reverse the direction of the drill. This will help loosen the bolt.
Increase Pressure Gradually: As the bolt loosens, gradually increase the pressure on the drill to continue extracting the bolt.
Use a Bolt Extractor if Needed: If the bolt is still too tight to remove, use a bolt extractor. Insert the extractor into the hole and twist it to grip the bolt.
Apply Penetrating Oil: If the bolt is severely rusted or stuck, apply penetrating oil around the bolt to help loosen it.
Tap the Bolt Gently: While using the reverse drill bit, gently tap the bolt with a hammer to help break it free.

If the bolt is still not coming out, it may be necessary to use other methods such as heat or an impact wrench. Always take precautions to avoid further damage to the workpiece and surrounding components.

Chemical Removal

Chemical solutions can dissolve the corrosion between the bolt and threads, allowing you to remove it without damaging the surrounding material. Here are the most effective chemical removal methods:

Penetrating Oil

Apply a penetrating oil, such as Liquid Wrench or PB Blaster, to the broken bolt. Let it soak for several hours or overnight to allow the oil to penetrate the threads. Then, try to remove the bolt using a wrench or pliers.

Vinegar

Create a solution of 50% white vinegar and 50% water. Apply the solution to the broken bolt and let it sit for several hours or overnight. The vinegar will dissolve the corrosion, making the bolt easier to remove.

Ammonia

Soak a rag in ammonia and wrap it around the broken bolt. Let it sit for several hours or overnight. The ammonia will break down the corrosion, allowing you to remove the bolt.

Heat

Apply heat to the broken bolt using a torch or heat gun. The heat will expand the metal, making the bolt easier to remove. Be careful not to overheat the bolt, as this could damage the surrounding material.

Impact Driver

Use an impact driver to apply a series of high-impact blows to the broken bolt. The impact force can break the bolt loose, making it easier to remove.

Extraction Tool

A bolt extractor is a specialized tool designed to remove broken bolts. The extractor is inserted into the broken bolt and used to turn it out.

Chemical	Effective Against
Penetrating Oil	Light to moderate corrosion
Vinegar	Mild to moderate corrosion
Ammonia	Moderate to heavy corrosion
Heat	Heavy corrosion
Impact Driver	Stubborn bolts
Extraction Tool	Broken bolts with enough material for the extractor to grip

How to Remove a Broken Bolt

Step 1: Gather Tools and Safety Gear

Before starting, ensure you have the necessary tools and safety gear, including a drill, drill bits, a center punch, a safety mask, and gloves.

Step 2: Create a Pilot Hole

Use a center punch to mark the center of the broken bolt and drill a pilot hole slightly smaller in diameter than the bolt itself. This will help guide the extraction tool and prevent further damage to the surrounding area.

Step 3: Use an Easy-Out Tool

Lubricate the threads of the broken bolt with penetrating oil or lubricant. Insert an Easy-Out tool (extractor) into the pilot hole and tap it gently with a hammer. Turn the tool counterclockwise to remove the broken bolt.

Step 4: Sever the Bolt

If the Easy-Out tool proves ineffective, use a hacksaw or reciprocating saw to cut a slot across the broken bolt. Drive a flathead screwdriver into the slot and turn it to split the bolt in half, then remove both pieces separately.

Step 5: Weld a Nut

If the bolt is too deeply embedded to access with tools, weld a nut onto the exposed end. Once the weld is cooled, use a wrench to turn the nut and remove the broken bolt.