Remove Broken Drill Bits: Effective Methods for Every Situation

Breaking a drill bit while working on a project is frustrating but fixable. Whether you’re dealing with a broken bit in metal, wood, or another material, this guide provides practical solutions to help you extract that stubborn broken bit and get back to work.

Understanding the Challenge of Broken Drill Bits

When a drill bit breaks inside your workpiece, it’s important to assess the situation before attempting removal. The approach you’ll take depends on several factors:

– How deep the broken bit is embedded
– The material you’re drilling into
– The type and size of the broken bit
– How much of the bit is protruding (if any)

Essential Tools for Removing Broken Drill Bits

Having the right tools on hand will make extraction much easier. Here’s what you might need:

Method 1: Extraction When the Bit is Protruding

If you’re lucky enough to have part of the drill bit protruding from the surface, this is the easiest scenario to remedy.

1. Grasp the protruding portion with serrated-jaw pliers or locking pliers.
2. Firmly grip the broken bit while applying steady pressure.
3. Twist the pliers counterclockwise (reverse of drilling direction) to back out the bit.
4. Apply penetrating oil if the bit doesn’t move easily, wait 5-10 minutes, then try again.
5. If the bit still won’t budge, tap the pliers gently with a hammer while maintaining counterclockwise pressure.

This method typically takes 5-10 minutes and works best when at least 1/8″ of the bit is protruding.

Method 2: Using a Screw Extractor

Screw extractors (also called easy-outs) are specifically designed for removing broken fasteners and can work well for drill bits too.

1. Select an extractor slightly smaller than the broken drill bit.
2. If needed, drill a small pilot hole in the center of the broken bit using a left-handed drill bit at slow speed.
3. Insert the extractor into the pilot hole, tapping it gently with a hammer if necessary.
4. Turn the extractor counterclockwise using a wrench or tap handle.
5. As the extractor bites into the broken bit, it should begin to back out.

This method typically takes 10-15 minutes and works best with larger broken bits (1/8″ or larger).

Tips for Successful Extractor Use

– Use cutting oil to keep the drill bit cool when creating the pilot hole
– Work slowly and patiently to avoid breaking the extractor
– If the extractor slips, try a slightly larger size or deepen the pilot hole

Method 3: The Welding Technique

For metalworking enthusiasts with access to welding equipment, this method can be particularly effective for stubborn bits broken flush or below the surface.

1. Clean the surface area around the broken bit thoroughly.
2. Take a metal rod or bolt that’s larger in diameter than the broken bit.
3. Weld the rod perpendicular (at a 90-degree angle) to the top of the broken bit.
4. Allow the weld to cool completely.
5. Use the rod as a lever, turning counterclockwise to extract the broken bit.

This method typically takes 15-20 minutes plus cooling time and requires welding skills and equipment.

Advanced Welding Technique with Copper Tube

For bits broken below the surface, try this specialized approach:

1. Find a copper tube with an inner diameter slightly larger than the broken bit.
2. Insert the tube into the hole until it surrounds the broken bit.
3. The copper tube acts as a liner, preventing the weld from sticking to the sides of the hole.
4. Weld a rod to the top of the broken bit, being careful to only weld to the bit and not the surrounding material.
5. Once cooled, use the rod to extract the bit.

This technique is particularly useful for extracting bits from blind holes in engine blocks or other critical components.

Method 4: Drilling Out the Broken Bit

If other methods fail, you may need to drill out the broken bit. This requires careful selection of the right drill bit for the job.

1. For standard high-speed steel (HSS) bits: Use a carbide drill bit slightly smaller than the broken bit.
2. For cobalt or titanium bits: Use a diamond-coated or solid carbide bit.
3. Center-punch the broken bit to create a starting point for your drill.
4. Drill very slowly with firm pressure, using cutting oil to keep the bit cool.
5. Once you’ve drilled through most of the broken bit, the remaining fragments can usually be picked out.

This method typically takes 20-30 minutes and requires patience and precision.

Important Considerations When Drilling Out Bits

– Always use eye protection
– Drill at low speeds to prevent overheating
– Apply cutting fluid liberally
– Take breaks to allow cooling if needed
– Be prepared to use multiple drill bits as they may dull quickly

Method 5: The Punch-Out Method

For through-holes, you may be able to punch out the broken bit from the opposite side.

1. Find a punch that fits loosely in the hole (old hard bolts or shanks of broken drill bits can work).
2. Position the punch against the broken bit from the opposite side.
3. Tap the punch firmly but carefully with a hammer.
4. Continue tapping with gradually increasing force until the bit begins to move.
5. Once loosened, the bit can often be pushed all the way through or grabbed with pliers.

This method typically takes 5-10 minutes and works best for through-holes in thinner materials.

Method 6: Creating a Slot for Screwdriver Extraction

If the broken bit is flush with the surface, you might be able to create a slot for extraction.

1. Use a Dremel tool with a cutting wheel or a small file to cut a slot across the exposed end of the broken bit.
2. Make the slot deep enough to accommodate a flat-head screwdriver.
3. Insert a screwdriver into the slot.
4. Apply downward pressure while turning counterclockwise to extract the bit.

This method typically takes 10-15 minutes and works best when the broken bit is flush with the surface.

Preventing Drill Bit Breakage

The best solution to broken drill bits is preventing breakage in the first place:

1. Use the correct speed for the material you’re drilling (slower for harder materials).
2. Apply cutting oil or lubricant for metal drilling.
3. Use sharp, high-quality drill bits appropriate for your material.
4. Apply steady, consistent pressure without forcing the bit.
5. Clear chips frequently, especially in deeper holes.
6. Drill pilot holes for larger bits.

Troubleshooting Common Issues

Problem: The Extractor Also Breaks

Solution: Extractors themselves can break if forced. If this happens, you may need to seek professional help or use more aggressive methods like EDM (Electrical Discharge Machining).

Problem: Can’t Get a Good Grip on the Bit

Solution: Try cleaning the area with compressed air and using a magnifying glass to better see what you’re working with. Sometimes creating a flat spot with a small file can help provide a better gripping surface.

Problem: Bit Is Too Hard to Drill Through

Solution: For extremely hard bits like cobalt, consider using a diamond grinding bit or seeking professional help with specialized equipment like EDM.

Problem: Can’t Center Your Drill on the Broken Bit

Solution: Use a center punch to create a dimple exactly in the center of the broken bit, or create a guide using a drill guide block.

When to Call a Professional

While most broken bits can be removed with the techniques described above, there are situations where professional help might be necessary:

– When working with expensive or irreplaceable materials
– When the broken bit is in a critical component (like an engine block)
– If multiple extraction attempts have failed
– When specialized equipment like EDM machines might be required

Machine shops and tool repair specialists have specialized equipment that can extract even the most stubborn broken bits without damaging your workpiece.

Conclusion

Breaking a drill bit doesn’t have to mean the end of your project. With the right approach and a bit of patience, you can successfully remove broken bits and continue your work. Remember to assess the situation carefully, choose the appropriate extraction method, and work methodically to avoid causing additional damage. And most importantly, take preventative measures in the future to minimize the chances of breaking bits in the first place.