What Causes a Bolt to Break?
Before we dive into the methods of removing a broken bolt, let’s understand why bolts break. There are several reasons why a bolt may snap off, including over-tightening, corrosion, and fatigue. Over-tightening a bolt can cause it to stretch beyond its elastic limit, leading to a fracture. Corrosion can weaken the bolt, making it brittle and prone to breakage. Fatigue is another common cause of bolt failure, which occurs due to repeated stress cycles.
Tools Required to Remove a Broken Bolt
To remove a broken bolt, you will need several tools, including a drill bit, drill machine, screw extractor, hammer, pliers, and a tap and die set. The drill bit is used to make a hole in the broken bolt, the screw extractor is used to grip the bolt, and the tap and die set is used to restore the threads.
Method 1: Using a Screw Extractor
One of the most effective methods of removing a broken bolt is by using a screw extractor. To use this method, drill a hole in the center of the bolt using a drill bit. Then, insert the screw extractor into the hole and turn it counter-clockwise using a wrench or pliers. The extractor will grip the bolt, allowing you to unscrew it.
Method 2: Using a Tap and Die Set
Another method of removing a broken bolt is by using a tap and die set. This method is suitable if the bolt has snapped off flush with the surface. First, drill a hole in the center of the bolt using a drill bit. Then, use a tap to create new threads inside the hole. Finally, use a die to thread a bolt into the new threads and unscrew the broken bolt.
Method 3: Using Heat
If the broken bolt is corroded or rusted, using heat can be an effective method of removal. Heat the surrounding area of the bolt using a propane torch until it turns red. Then, use pliers or a wrench to turn the bolt counter-clockwise while it’s still hot. The expansion and contraction caused by the heat will break the rust or corrosion, allowing the bolt to turn.
Method 4: Using a Left-Handed Drill Bit
Using a left-handed drill bit is another effective method of removing a broken bolt. These drill bits are designed to turn in the opposite direction to a regular drill bit. Start by drilling a small hole in the center of the broken bolt using a left-handed drill bit. As you drill, the bit will grip onto the bolt and turn it counter-clockwise, allowing you to remove it.
Preventing Bolt Breakage
Preventing bolt breakage is always better than having to remove a broken bolt. Here are some tips to prevent bolt breakage:
- Use the correct torque specification when tightening bolts.
- Apply an anti-seize compound to bolts that are exposed to heat or moisture.
- Inspect bolts regularly for signs of corrosion or fatigue.
- Replace worn or damaged bolts before they fail.
FAQs
Q: Can I use pliers to remove a broken bolt?
Yes, you can use pliers to turn the broken bolt counter-clockwise. However, this method is only suitable if the bolt is sticking out of the surface.
Q: What is the best method to remove a broken bolt?
The best method of removing a broken bolt depends on the situation. Using a screw extractor or a tap and die set is usually the most effective method.
Q: Can I use a regular drill bit to remove a broken bolt?
Yes, you can use a regular drill bit to remove a broken bolt. However, a left-handed drill bit is more effective as it can turn the bolt counter-clockwise while drilling.
Conclusion
Removing a broken bolt can be a challenging task, but with the right tools and techniques, it can be done. Using a screw extractor, a tap and die set, heat, or a left-handed drill bit are all effective methods of removing a broken bolt. Remember to always use the correct torque specification when tightening bolts and inspect them regularly to prevent breakage.