Buzz
A bolt is a metal component commonly used to join two or more objects together. Although it is a rare occurrence, bolts can break during the construction or installation process. This is often due to inexperience or hurried work. For construction projects or home improvement upgrades, knowing how to remove a broken bolt is an essential skill to possess.
Steps
Use a Bolt Removal Tool Set
Place the punch tip directly in the center of the broken bolt, as close to the center as possible. Strike the punch with a hammer to mark the center of the bolt. This step ensures you drill precisely into the center of the bolt, minimizing the risk of damaging its threads.
Drill a pilot hole into the center of the broken bolt using a reverse drill bit. The reverse drill bit has counter-clockwise threads, which means when you operate your drill in reverse, the bit moves inward. You need to use this type of drill bit because it generates a twisting force that loosens the bolt rather than tightening it.
- If you're lucky, the reverse drill bit might bite into the bolt and start to loosen it. You can then use pliers to grip it and remove it completely.
- Make sure to use the correct size drill bit. Drill bit sets typically include a guide that tells you which size to use based on the bolt you're removing. Using a bit that's too large may damage the bolt's threads, while a bit that's too small could require a smaller, weaker extractor that could break during the removal process.
Insert a matching extractor bit into the hole you just drilled. Depending on the extractor tool set, the extractor bit may have a reverse drill bit on one end and either a hexagonal or T-handle attachment on the other. Since the extractor bit is also a reverse drill bit, it will engage with the bolt in a counter-clockwise motion.
- Because the extractor bit has a tapered end, you'll need to tap it into place with a hammer before attaching it to the T-handle or drill.
Remove the broken bolt. As you drill the extractor bit into the bolt, the resulting torque will loosen the bolt once the extractor’s head locks into place.
- Keep turning the extractor counter-clockwise until the broken bolt is completely removed from the surface it’s attached to.
- Proceed slowly to avoid damaging the bolt or the material it's attached to. Also, handle the extractor carefully since it's made of hardened steel; a broken extractor is even more difficult to remove than the bolt itself.
Clean off the metal shavings. During the bolt removal process, metal debris will come off the bolt. If you're replacing the bolt with a new one, it’s crucial to thoroughly clean the metal shavings from the hole. You can use a magnet or compressed air to clear the shavings out.
Use welding techniques
Place the punch directly in the center of the bolt shaft, as close to the middle as possible. Just like using a bolt removal tool, you'll need a hammer and punch to mark the center of the bolt.
Drill a hole at the center of the bolt. Use a drill bit about one-quarter the diameter of the bolt to drill a pilot hole.
- This method is typically used for bolts that are so rusted that removal tools won't work. You don't need to worry about the bolt tightening from drilling with a clockwise bit, although drilling with a counterclockwise bit would be more effective.
Screw the hex nut onto the bolt. You'll screw the nut onto the bolt, no matter how many threads remain exposed. Tighten the nut securely, but back it off by half a turn to avoid it fully touching the bolt head surface.
Weld the nut onto the bolt. This is a basic spot weld, but it still requires some welding experience. If you're new to welding, you should ask someone experienced to do the weld, or practice welding on other materials with online guides first.
- Be especially careful if the bolt head surface could melt into the bolt or the nut. For this reason, this method works best on aluminum, as aluminum doesn’t easily weld to steel.
Remove the broken bolt. Once the weld has cooled, the nut will essentially be welded in place like a new bolt head, allowing you to unscrew it with a pipe wrench or adjustable spanner.
- The weld is quite strong, but it can still break. For bolts with severe rust, you may need to weld the nut in multiple spots.
- To break the corrosion bond, begin by turning the bolt slowly back and forth. Once the bolt loosens, continue rotating in both directions, but rotate counterclockwise more often until you can finally remove the bolt.
Warning
- Handle the withdrawal bit slowly and avoid applying too much force. If the bit breaks inside the bolt, you will need a drill bit stronger than the steel of the withdrawal bit to extract it.
- Take necessary protective measures when using welding methods, including wearing a jacket, safety mask, gloves, long pants, and boots.
- Wear protective eyewear when drilling, as metal shavings can fly into your eyes.
Items You Will Need
- Drill
- Counterclockwise Drill Bit
- Withdrawal Bit
- T-handle
- Pliers
- Magnet
- Hammer
- Punch
- Compressed Air
- Hex Nut
- Welding Machine
- Welding Protective Mask
- Welding Protective Jacket
- Gloves
- Safety Glasses
