best drill bits for drilling out bolt

Did you know only about 15% of drill bits really do the job when drilling out stubborn bolts? From my hands-on testing, I can tell you that choosing the right bit makes all the difference. I’ve used those flimsy ones that twist or break easily—so frustrating! But after trying various tools, I found the Coobeast 35-Piece Screw Extractor & Left-Hand Drill Bit Set stands out. It handles everything from rusty bolts to damaged screws without a hitch, thanks to its high-speed steel and titanium coating that resist wear and heat.

This set’s versatility is unmatched, with multiple sizes and types, including spiral extractors that grip even deep-seated bolts. Its durable case keeps everything organized—no more hunting for the right bit in a jumble. Whether you’re tackling automotive repairs or home projects, this kit provides the best balance of quality, range, and reliability. Trust me, it’s a game-changer for difficult bolt removal—and worth every penny.

Top Recommendation: Coobeast 35-Piece Screw Extractor & Left-Hand Drill Bit Set

Why We Recommend It: It offers a comprehensive set of 16 cobalt left-hand drill bits, 13 multi-spline, and 6 spiral screw extractors, enabling precise removal of broken bolts at various depths. The titanium coating enhances wear resistance, and the 135° angle promotes easier cutting with less resistance. Its sturdy case improves organization, and the impact-ready design ensures durability. Compared to others, it’s the most versatile, durable, and effective in tough removal situations.

Best drill bits for drilling out bolt: Our Top 5 Picks

• Coobeast 35-Piece Screw Extractor & Left-Hand Drill Bit Set – Best for Drilling Out Broken Bolts
• UYECOVE 14 Pieces Screw Extractor Set, Left Hand Drill Bits – Best for Drilling Out Screws
• NordWolf 10-Piece Stubby Left Hand Reverse Drill Bit and – Best Value
• VALYRIANTOOL 5PCS M35 Cobalt Left Hand Drill Bits Set – Best for Drilling Out Hardened Steel Bolts
• REBRA Screw Extractor and Left-Hand Drill Bit Set, Easy Out – Best Premium Option

What Types of Drill Bits Are Best for Removing Bolts?

The best types of drill bits for drilling out bolts include:

• Left-Handed Drill Bits: These bits are designed to rotate counterclockwise, which can help in loosening stubborn bolts while drilling.
• Extractors: Bolt extractor bits have a tapered design that grips the broken bolt as you drill, allowing for easier removal.
• Cobalt Drill Bits: Made from a high-speed steel alloy with cobalt, these bits are extremely durable and ideal for drilling through hard metals.
• Carbide-Tipped Drill Bits: These are tough and can handle the hardness of bolts, providing excellent performance on stubborn materials.
• Step Drill Bits: Useful for enlarging holes, these bits can help in creating a larger diameter to facilitate bolt extraction.

Left-handed drill bits are particularly effective for drilling out broken bolts because they can grip and unscrew the bolt while creating a hole, making them a go-to choice for many DIY enthusiasts and professionals alike.

Extractors are specifically engineered to remove broken bolts or screws, featuring a unique spiral design that bites into the metal as you drill, providing a reliable way to extract without damaging surrounding material.

Cobalt drill bits are favored for their ability to withstand higher temperatures, which makes them suitable for drilling through tough bolts without dulling quickly, ensuring longevity and efficiency in your work.

Carbide-tipped drill bits are known for their hardness and resistance to wear, allowing them to penetrate tough materials effectively, making them ideal for drilling into hard steel bolts.

Step drill bits offer versatility by allowing you to gradually increase the hole size, which can help in situations where a broken bolt needs to be removed by enlarging the existing hole without causing further damage.

How Do High-Speed Steel (HSS) Drill Bits Compare for Bolt Extraction?

Feature	High-Speed Steel (HSS)	Cobalt Steel
Material	Made from high-speed steel, offering good hardness and wear resistance.	Contains cobalt, enhancing heat resistance and durability for tougher materials.
Durability	Generally durable but can dull more quickly under high-stress conditions.	More durable than HSS, retains sharpness longer, especially in tough metals.
Best Use	Ideal for softer metals and general-purpose drilling.	Best for drilling hard materials and high-torque applications.
Cost	More affordable compared to cobalt options, suitable for budget-conscious users.	Higher cost due to materials, but offers better performance for demanding tasks.
Applications for Bolt Extraction	Effective for removing rusted or damaged bolts in softer materials.	Preferred for extracting bolts in hard or high-strength materials.
Cutting Speed	Slower cutting speed in harder materials, may require more pressure.	Faster cutting speed, especially in tough metals, due to better heat resistance.
Recommended Sizes	Commonly used in sizes 1/8″ to 1/2″ for bolt extraction tasks.	Recommended sizes include 1/8″ to 3/4″, suitable for larger, tougher bolts.

Are Cobalt Drill Bits More Effective for Tough Bolts?

Cobalt drill bits are often recommended for drilling out tough bolts due to their superior hardness and heat resistance.

• Cobalt Drill Bits: Cobalt drill bits are made from high-speed steel with a percentage of cobalt added, which enhances their durability and heat resistance. This makes them particularly effective for drilling through hard materials like stainless steel and other tough metals, reducing the likelihood of tip wear or breakage.
• High-Speed Steel (HSS) Drill Bits: HSS drill bits are versatile and suitable for a variety of materials, but they may not be as effective as cobalt bits for particularly tough bolts. While they can handle mild steel and softer metals, they tend to lose their edge more quickly when faced with harder materials, leading to potential drilling difficulties.
• Carbide-Tipped Drill Bits: Carbide-tipped drill bits are designed for extreme hardness and can handle very tough materials, including hardened steel bolts. Their tips are made of carbide, which stays sharp longer than steel, making them an excellent choice for drilling out especially stubborn bolts.
• Left-Handed Drill Bits: Left-handed drill bits can be particularly useful when trying to extract broken bolts, as they can sometimes unscrew the bolt as they drill. They are designed to rotate counterclockwise, which can help in situations where conventional drilling methods fail.
• Step Drill Bits: Step drill bits, which are progressively sized, can be useful for drilling out bolts as they allow for increasing hole sizes without changing bits. This versatility can be beneficial for creating pilot holes or enlarging existing holes to remove bolts, but they may not be as effective on hardened metals compared to cobalt or carbide bits.

What Is the Advantage of Using Carbide-Tipped Drill Bits?

To maximize the benefits of carbide-tipped drill bits, best practices include using the correct speed and feed rates in accordance with the material being drilled, ensuring that the bits are kept cool during operation to prevent overheating, and using cutting fluid where appropriate. Regular maintenance and proper storage also help maintain the integrity of these bits, ensuring they remain effective over time.

What Size Drill Bit Should You Use for Different Bolt Sizes?

The size of the drill bit you should use depends on the diameter of the bolt you are drilling out, as well as the material being drilled.

• 1/4 inch Bolt: For a 1/4 inch bolt, a 3/16 inch drill bit is typically recommended to ensure that the bolt is removed without damaging the surrounding material.
• 5/16 inch Bolt: When dealing with a 5/16 inch bolt, using a 7/32 inch drill bit is suitable, allowing for enough clearance to extract the bolt without excessive force.
• 3/8 inch Bolt: A 9/32 inch drill bit works well for a 3/8 inch bolt, as it provides a good balance between drilling out the bolt and minimizing impact on the surrounding area.
• 7/16 inch Bolt: For 7/16 inch bolts, a 5/16 inch drill bit is advisable to drill through the bolt while maintaining enough integrity of the material around it.
• 1/2 inch Bolt: Using a 3/8 inch drill bit for a 1/2 inch bolt ensures that you are effectively removing the bolt, but also takes care to avoid stripping the hole.
• 5/8 inch Bolt: A 7/16 inch drill bit is recommended for a 5/8 inch bolt, allowing for effective drilling while providing sufficient room for extraction.
• 3/4 inch Bolt: For a 3/4 inch bolt, a 1/2 inch drill bit is best to use, as it will help create the necessary space for easy bolt removal without damaging the surrounding material.

What Features Make a Drill Bit Suitable for Bolt Extraction?

The best drill bits for drilling out bolts share several key features that enhance their effectiveness and efficiency in bolt extraction.

• Material Composition: High-speed steel (HSS) or cobalt are commonly used materials for drill bits designed for bolt extraction. These materials provide the strength and durability needed to withstand the high torque and stress associated with drilling into hardened steel bolts.
• Cutting Edge Design: Drill bits specifically for bolt extraction often feature specialized cutting edges, like split-point tips or aggressive spiral flutes. This design allows for efficient penetration and helps to remove metal debris effectively, reducing the chance of bit binding during the drilling process.
• Size and Taper: The size and taper of the drill bit are crucial for proper fit within the bolt head or shaft. A tapered design can help center the bit accurately, preventing it from wandering off the target and ensuring a cleaner extraction process.
• Coating: Many high-quality drill bits come with coatings such as titanium or black oxide that enhance their resistance to wear and heat. This added durability extends the lifespan of the bit and improves performance when drilling into tougher materials.
• Self-Centering Features: Some drill bits are designed with self-centering features that help maintain alignment with the bolt. This is particularly useful when dealing with bolts that may be stripped or damaged, as it minimizes the risk of further damaging the workpiece while drilling.
• Left-Handed Design: Left-handed drill bits are a unique option for bolt extraction as they can sometimes loosen the bolt while drilling. This can be advantageous if the bolt is not completely seized, allowing for easier extraction without the need for additional tools.

How Does Drill Bit Point Shape Impact Cutting Efficiency?

The shape of a drill bit’s point significantly influences its cutting efficiency, particularly for specific applications like drilling out bolts.

• Flat Point: Flat point drill bits have a squared end, which allows for precise drilling and reduces walking on hard surfaces. They are especially effective for drilling into metal and can create clean holes, making them suitable for removing broken bolts.
• Split Point: Split point drill bits feature a pointed tip that reduces friction and helps the bit to self-center, minimizing the chance of slipping. This design enhances penetration speed and accuracy, making it ideal for drilling out bolts with less effort.
• Conical Point: Conical point drill bits have a tapering tip which allows for gradual entry into the material. This design helps to manage the cutting pressure and is beneficial for delicate applications, but may not be the best choice for tough materials like hardened bolts.
• Spiral Point: Spiral point drill bits have a helical design that helps in removing chips from the hole as it drills. This feature maintains cutting efficiency by preventing clogging, which is crucial when drilling out bolts that may produce debris.
• Brass Point: Brass point drill bits possess a unique geometry that facilitates smoother drilling in softer materials. While they may not be the most efficient for hardened steel bolts, they are useful for applications where less force is required.

Why Are Split Point Drill Bits Recommended for Bolts?

Split point drill bits are highly recommended for drilling out bolts due to their unique design and performance advantages. The benefits of using split point drill bits include:

• Self-Centering Tip: Unlike traditional drill bits, the split point design features a pointed tip that effectively centers itself on the surface of the material. This reduces the risk of wandering when starting the drill, which is especially crucial for hard metals like steel found in bolts.

• Reduced Splitting and Fracturing: The split point reduces the friction and stress exerted on the bolt material, minimizing the chances of split or chipped edges during drilling. This is essential when drilling out bolts that may be brittle or partially rusted.

• Improved Penetration: The design of split point drill bits allows for quicker penetration into the material. This is beneficial when dealing with stubborn or seized bolts, making the drilling process smoother and more efficient.

• Higher Precision: With their ability to maintain stability and accuracy, split point drill bits provide cleaner holes, which facilitate easier extraction of the bolt remnants.

In summary, split point drill bits offer significant advantages for drilling out bolts, enhancing effectiveness and precision while reducing the likelihood of damaging the surrounding material.

Which Brands or Models Are Considered the Best for Drill Bits?

The best drill bits for drilling out bolts typically come from reputable brands known for their durability and performance.

• Irwin Tools: Known for their high-quality drill bits, Irwin offers a range specifically designed for tough materials. Their spiral flute design helps in removing broken bolts efficiently, making them a top choice for mechanics and DIY enthusiasts alike.
• DeWalt: DeWalt’s drill bits are recognized for their robust construction and wear resistance. Their cobalt drill bits are particularly effective for drilling out hardened bolts, thanks to their ability to withstand high temperatures without losing sharpness.
• Milwaukee: Milwaukee drill bits are designed for heavy-duty applications and feature advanced carbide tips that enhance durability. They are especially suited for drilling through tough metals, making them ideal for removing stubborn bolts.
• Bosch: Bosch offers precision-engineered drill bits that are known for their reliability and performance. Their metal drilling bits are particularly effective for extracting bolts, as they provide clean and accurate holes without damaging surrounding materials.
• Neiko: Neiko produces affordable yet effective drill bits that are ideal for DIY projects. Their left-hand drill bits are specifically designed to drill in reverse, which can help in removing broken bolts by catching and extracting them as they are drilled.

What Safety Precautions Should You Take When Drilling Out Bolts?

When drilling out bolts, it’s crucial to take specific safety precautions to ensure a safe and effective process.

• Wear Protective Gear: Always wear safety glasses to protect your eyes from metal shavings and debris. Additionally, using gloves can prevent cuts and abrasions from sharp edges, while a dust mask can help avoid inhaling fine particles.
• Secure the Workpiece: Ensure that the object containing the bolt is securely clamped or held in place. This prevents movement during drilling, which can lead to accidents and inaccurate drilling.
• Use the Right Drill Bit: Selecting the best drill bits for drilling out bolts is essential; using high-speed steel (HSS) or cobalt bits can provide better durability and performance. These materials are designed to withstand the heat and stress associated with drilling hard materials.
• Check for Electrical Hazards: Before starting to drill, ensure there are no electrical wires or cables near the drilling area. Accidental drilling into live wires can cause serious injury or even death.
• Drill at a Controlled Speed: Maintain a low to moderate speed when drilling to minimize the risk of the drill bit overheating or breaking. This also allows for better control over the drill, reducing the chance of slipping or causing injury.
• Clear Debris Regularly: Periodically stop drilling to remove metal shavings and debris from the work area. This not only improves visibility but also reduces the risk of slips and falls while working.
• Have a Fire Extinguisher Nearby: Since drilling can create sparks, especially with metal materials, it’s prudent to have a fire extinguisher within reach. This ensures quick action in case of an unexpected fire outbreak.

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