Master the art: how to drill out a broken bolt like a pro

If you’ve ever encountered the frustrating predicament of a broken bolt, you know how it can bring your project to a screeching halt. But don’t despair! Drilling out a broken bolt is not as daunting as it may seem. With the right tools, techniques, and a bit of patience, you can successfully remove the broken bolt and resume your project.

Tools You’ll Need

Before you embark on your bolt-drilling mission, gather the essential tools:

• Electric drill
• Drill bits (various sizes)
• Bolt extractor
• Center punch
• Hammer
• Safety glasses
• Gloves

Safety First

Always prioritize safety when working with power tools. Wear safety glasses and gloves to protect yourself from flying debris and sharp edges. Securely clamp the workpiece to prevent it from moving while drilling.

Step-by-Step Guide

1. Mark the Center

Use a center punch and hammer to create a small indent in the center of the broken bolt. This will guide the drill bit and prevent it from wandering off-center.

2. Start with a Small Drill Bit

Begin drilling with a small drill bit, around 1/16 inch. Gradually increase the bit size as you drill deeper. This will minimize the risk of damaging the surrounding material.

3. Drill Slowly and Straight

Apply gentle pressure and drill slowly to avoid overheating the bit. Keep the drill perpendicular to the surface to ensure a straight hole.

4. Use a Bolt Extractor

Once you’ve drilled a hole deep enough, insert a bolt extractor. This specialized tool has reverse threads that will grip the broken bolt and allow you to unscrew it.

5. Apply Penetrating Oil

If the bolt is particularly stubborn, apply some penetrating oil to the hole and let it sit for a few minutes. This will help loosen the grip of the broken bolt.

6. Reverse the Drill

Switch your drill to the reverse setting and slowly unscrew the bolt extractor, bringing the broken bolt with it.

7. Clean Up

Once the broken bolt is removed, clean up the hole and threads with a tap or a thread chaser to ensure proper fitment of the new bolt.

Tips for Success

• Use sharp drill bits to reduce the risk of breaking.
• Lubricate the bits with cutting fluid to extend their life.
• If the bolt is made of hardened steel, use a carbide-tipped drill bit.
• If the broken bolt is stuck in a blind hole, consider using a left-handed drill bit or creating a small notch in the bolt head.
• Be patient and don’t force the drill. If you encounter resistance, back off and try again.

What to Do if You Can’t Drill Out the Bolt

In rare cases, you may encounter a broken bolt that simply won‘t budge. If drilling out is not an option, consider these alternatives:

• Weld a Nut: Weld a nut onto the broken bolt and use a wrench to unscrew it.
• Use a Dremel Tool: Carefully cut a slot into the broken bolt head and use a flathead screwdriver to remove it.
• Call a Professional: If all else fails, seek the assistance of a professional mechanic or machinist who has specialized tools and experience in removing broken bolts.

Quick Answers to Your FAQs

1. Can I use a regular drill bit to drill out a bolt?

Yes, but it’s recommended to use a drill bit specifically designed for metal, such as a high-speed steel (HSS) bit.

2. How deep should I drill into the bolt?

Drill deep enough to create a hole that is slightly wider than the diameter of the broken bolt.

3. What if the broken bolt is flush with the surface?

Use a center punch to create a small dimple in the center of the bolt. Alternatively, you can use a Dremel tool to grind down the bolt head slightly.

4. What type of bolt extractor should I use?

There are different types of bolt extractors, including square-drive and spiral-flute extractors. Choose one that is appropriate for the size and material of the broken bolt.

5. Can I reuse the hole after drilling out the bolt?

Yes, but it’s important to clean and tap the hole to ensure a proper fit for the new bolt.