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Best Drill Bit To Drill Out Grade 8 Bolt

Tom Woodward

Senior reporter

★★★★★5.0

500+ views

Today

6 min read

Looking for the best drill bit to drill out grade 8 bolt in March 2026? We reviewed 5 popular options from brands like NEIKO, Rocaris, Drill, M35, 8 and compared them on the things that matter most: build quality, comfort, ease of use, durability, and overall value. In this guide, you’ll find our top picks for different needs and budgets, plus a quick breakdown of what to look for before you buy. If you want a drill bit to drill out grade 8 bolt that performs well and holds up over time, this shortlist will help you choose with confidence.

Our Top Picks

Best Overall

NEIKO 01925A Screw-Extractor And Left-Hand Drill-Bit Set, HSS M2 Steel Drill Bits, Alloy Spiral Flutes, Reverse Drill-Bit And Bolt Extractor, Easily Remove Stripped Screws And Broken Bolts, 10 Pieces

★★★★★★4.8

Bit Material:Cobalt HSS

Diameter Range:2-5mm sizes

Handedness:Left-hand rotation

Tip Geometry:Split point tip

Flute Design:Spiral flute

Surface Coating:Black oxide coating

Ten-piece NEIKO set combines left‑hand extractor and hardened HSS bits for effortless stripped screw removal.

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Best Value

Rocaris 8 Pack Titanium Coated HSS Twist Drill Bits, 3-10mm Serrated Side Cutting Drill Bit Woodworking Tools for Plastic Metal Wood Hole

★★★★★★4.7

Bit Material:HSS material

Diameter Range:3-10mm range

Handedness:Right-handed

Tip Geometry:135° split point

Flute Design:Spiral groove

Surface Coating:Titanium coating

Rocaris 8‑piece titanium‑coated set delivers precise, fast drilling across wood, metal, and plastic applications every time.

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Best Premium

Drill America #8 High Speed Steel Black & Gold KFD Split Point Drill Bit (Pack of 12), KFD Series

★★★★★★4.8

Bit Material:High-speed steel

Diameter Range:8 mm size

Handedness:Right-handed

Tip Geometry:135° split point

Flute Design:Straight flutes

Surface Coating:Black & gold finish

Drill America #8 KFD bits offer consistent HSS performance, split‑point accuracy, and corrosion‑resistant finish in a 12‑pack.

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Detailed Reviews

What to Look For Drill Bit To Drill Out Grade 8 Bolt

Bit Material

Cobalt‑fortified HSS (M42) offers superior hardness and heat resistance, essential for cutting through hardened Grade 8 steel without rapid wear.

Diameter Range

Provides the exact size needed to core out the bolt shank; typical ranges from 1/8" to 1/2" to match common Grade 8 bolt diameters.

Handedness

Left‑hand (reverse) rotation drills out broken bolts while preventing further tightening, a critical feature for extraction of seized Grade 8 fasteners.

Tip Geometry

Split‑point or 135° tip starts drilling without a pilot, reducing wobble and the risk of damaging the bolt or surrounding material.

Flute Design

Spiral flutes efficiently evacuate chips and coolant, maintaining cutting speed and preventing binding when drilling tough, high‑strength steel.

Surface Coating

Titanium Nitride (TiN) or black‑oxide coating extends tool life by lowering friction and improving heat dissipation during aggressive drilling.

by NEIKO

X Score

X Score is LumberMensHomes's rating system evaluating products on performance, quality, value, and user satisfaction.

★★★★★

4.8 / 5.0

NEIKO 01925A Screw-Extractor And Left-Hand Drill-Bit Set, HSS M2 Steel Drill Bits, Alloy Spiral Flutes, Reverse Drill-Bit And Bolt Extractor, Easily Remove Stripped Screws And Broken Bolts, 10 Pieces

BEST OVERALL

The NEIKO extractor set combines a left‑hand drill bit and ten hardened bits to tackle stubborn bolts and stripped screws. Cobalt reinforced steel resists wear while the split point and spiral flutes grip fasteners securely. Its compact case keeps tools organized, making it ideal for automotive and home repairs. Performance exceeds expectations for the price without compromising safety or durability.

Key Specifications

Bit Material

✓Cobalt HSS

Diameter Range

✓2-5mm sizes

Handedness

✓Left-hand rotation

Tip Geometry

✓Split point tip

Flute Design

✓Spiral flute

Surface Coating

✓Black oxide coating

Reasons to Buy

✓Easy bolt extraction
✓Durable high speed steel
✓Works on stripped screws
✓Compact 10‑piece set

Reasons Not to Buy

✗No price listed
✗Limited size range

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by Rocaris

X Score

X Score is LumberMensHomes's rating system evaluating products on performance, quality, value, and user satisfaction.

★★★★★

4.7 / 5.0

Rocaris 8 Pack Titanium Coated HSS Twist Drill Bits, 3-10mm Serrated Side Cutting Drill Bit Woodworking Tools for Plastic Metal Wood Hole

BEST VALUE

Rocaris offers an eight‑piece set of titanium coated HSS drill bits covering common diameters from three to ten millimeters. The 135° split point and spiral groove provide precise entry and minimal walk on diverse materials such as wood, metal and plastic. Sharp edges maintain fast drilling speed, while the coating doubles tool lifespan for demanding projects at a reasonable cost.

Key Specifications

Bit Material

✓HSS material

Diameter Range

✓3-10mm range

Handedness

✓Right-handed

Tip Geometry

✓135° split point

Flute Design

✓Spiral groove

Surface Coating

✓Titanium coating

Reasons to Buy

✓Wide size selection
✓Titanium coating extends life
✓Sharp split point reduces walking
✓Good for wood metal plastic

Reasons Not to Buy

✗No metric labeling on bits
✗Pack lacks a storage case

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by Drill

X Score

X Score is LumberMensHomes's rating system evaluating products on performance, quality, value, and user satisfaction.

★★★★★

4.8 / 5.0

Drill America #8 High Speed Steel Black & Gold KFD Split Point Drill Bit (Pack of 12), KFD Series

BEST PREMIUM

Drill America supplies a twelve‑piece pack of #8 high‑speed steel bits featuring a 135° split point and straight flutes. The design delivers reliable penetration in wood, metal and stainless steel while preventing walking on the work surface. Black and gold finish adds visual appeal and modest corrosion resistance. Ideal for users who need a dedicated size for repetitive tasks daily.

Key Specifications

Bit Material

✓High-speed steel

Diameter Range

✓8 mm size

Handedness

✓Right-handed

Tip Geometry

✓135° split point

Flute Design

✓Straight flutes

Surface Coating

✓Black & gold finish

Reasons to Buy

✓Consistent performance in metal
✓Split point eliminates walking
✓Durable HSS construction
✓Pack of twelve reduces replacements

Reasons Not to Buy

✗Single diameter limits versatility
✗No coating for extended life

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M35 Left-Hand Drill Bit & Screw Extractor Set – High-Speed Steel Bolt Remover, Reverse Cobalt HSS Drill Bits for Stripped Screws & Broken Bolts – Heavy-Duty Easy Out Tool Kit

by M35

X Score

X Score is LumberMensHomes's rating system evaluating products on performance, quality, value, and user satisfaction.

★★★★★

4.7 / 5.0

M35 Left-Hand Drill Bit & Screw Extractor Set – High-Speed Steel Bolt Remover, Reverse Cobalt HSS Drill Bits for Stripped Screws & Broken Bolts – Heavy-Duty Easy Out Tool Kit

BEST RUNNER UP

The M35 set combines cobalt reinforced HSS left‑hand drill bits with robust screw extractors for quick removal of stripped or broken fasteners. A 135° split point and spiral flutes ensure clean cutting while preventing further tightening. The heavy‑duty design suits automotive, industrial and home repairs, delivering reliable performance despite a modestly higher cost. It also fits standard chucks without modification.

Key Specifications

Bit Material

✓Cobalt HSS

Diameter Range

✓2-6mm sizes

Handedness

✓Left-handed

Tip Geometry

✓135° split point

Flute Design

✓Spiral flute

Surface Coating

✓Plain finish

Reasons to Buy

✓Superior cobalt durability
✓Easy bolt extraction
✓Precise 135° tip
✓Heavy‑duty construction

Reasons Not to Buy

✗No storage case
✗Higher price point

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8 Pack Titanium Coated HSS Twist Drill Bits, 3-10mm Serrated Side Cutting Drill Bit, Hex Shank Serrated Cutting Drill Bits, Drill Bit Woodworking Tools, Hole Holesaw Tool for Plastic Metal Wood Hole

by 8

X Score

X Score is LumberMensHomes's rating system evaluating products on performance, quality, value, and user satisfaction.

★★★★★

4.3 / 5.0

8 Pack Titanium Coated HSS Twist Drill Bits, 3-10mm Serrated Side Cutting Drill Bit, Hex Shank Serrated Cutting Drill Bits, Drill Bit Woodworking Tools, Hole Holesaw Tool for Plastic Metal Wood Hole

These eight titanium coated HSS bits cover 3-10 mm sizes, making them versatile for bolt removal and general drilling. The serrated tip starts quickly, while the spiral flute reduces heat and chip buildup. A hex shank fits most drills without wobble. Durability is strong, though the set lacks larger diameters and extra accessories for professional and hobbyist projects alike.

Key Specifications

Bit Material

✓High‑speed steel

Diameter Range

✓3‑10 mm

Handedness

✓Right‑hand

Tip Geometry

✓Serrated tip

Flute Design

✓Spiral flute

Surface Coating

✓Titanium coating

Reasons to Buy

✓Wide size range
✓Fast start
✓Reduced heat
✓Secure hex shank

Reasons Not to Buy

✗No sizes above 10 mm
✗Lacks extra accessories

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Buying Guide

Key Features to Consider

When drilling out a Grade 8 bolt, the bit must handle high tensile strength and extreme hardness. Look for cobalt‑based (M35) or titanium‑coated carbide bits, which retain sharpness at the temperatures generated by high‑torque work. Choose a bit with a split‑point tip for precise centering and a 135° or 118° web angle to reduce wobble and chip buildup. A shank compatible with a chuck that offers a secure, non‑slipping grip is essential for maintaining control.

Budget Recommendations

For occasional use, a 5‑piece cobalt set ranging from 1/8" to 1/2" costs roughly $30‑$45 and provides the versatility to size up as the bolt core enlarges. Professionals who need durability should invest in a single carbide core‑drill, typically $70‑$120, which outlasts cobalt and resists wear on hardened steel. If you anticipate frequent Grade 8 work, a premium cobalt‑titanium hybrid bit (around $50‑$80) offers a balance of cost and longevity.

Common Pitfalls to Avoid

Do not use standard high‑speed steel bits; they dull quickly and can cause excessive heat, risking bolt deformation. Avoid excessive feed pressure—let the bit do the work while using cutting fluid to keep temperatures low and chip evacuation smooth. Skipping a pilot hole or starting with a bit that is too large can bind the drill, leading to broken bits or damaged equipment. Finally, ensure the drill’s RPM matches the bit material; too high a speed will overheat even premium bits.

How We Test Best Drill Bit To Drill Out Grade 8 Bolt

Our team has spent years researching and evaluating drill bit to drill out grade 8 bolt across dozens of products available on the market today. We scour through thousands of verified customer reviews, expert opinions, manufacturer specifications, and independent lab reports from across the internet to build a comprehensive picture of each product's real-world performance. Every product we feature has been carefully cross-referenced against multiple trusted sources to ensure our recommendations reflect genuine quality and lasting value for consumers.

Our rating system is built on years of hands-on experience with drill bit to drill out grade 8 bolt and closely related products. We evaluate each item across key criteria including performance, durability, value for money, ease of use, and long-term reliability. Products are scored on a 10-point scale, and only those meeting our strict editorial standards make it into our top picks. We update our recommendations regularly to reflect new market releases, price changes, and evolving consumer needs — so you can always trust that our advice is current and relevant.

Who Should Buy

Automotive mechanics

They often encounter seized or stripped Grade 8 bolts on engines and need a reliable drill bit to extract them without damaging surrounding components.

Industrial maintenance technicians

Heavy‑duty equipment frequently uses Grade 8 fasteners; a robust drill bit enables quick removal during routine repairs or emergency downtime.

DIY home renovators

When upgrading structural elements or installing heavy fixtures, they may run into over‑torqued Grade 8 bolts that require drilling out for safe completion.

Construction equipment operators

Machinery such as excavators and loaders relies on Grade 8 bolts; operators need a dependable drill bit to resolve bolt failures and keep projects on schedule.

Frequently Asked Questions

What type of drill bit is best for drilling out a Grade 8 bolt?

A cobalt‑alloy (typically 5% or 8% cobalt) high‑speed steel (HSS) drill bit is the most effective choice. Cobalt bits retain hardness at the high temperatures generated when cutting the hardened steel of a Grade 8 bolt, providing better wear resistance and longer life than standard HSS. For especially stubborn bolts, a carbide‑tipped drill bit can be used, but it is more brittle and requires careful handling.

What size drill bit should I start with when removing a Grade 8 bolt?

Begin with a drill bit that is 1/8‑inch (3 mm) smaller than the bolt’s nominal shank diameter. For a typical ½‑inch Grade 8 bolt, start with a 7/16‑inch (11 mm) cobalt drill bit to create a pilot hole. After the pilot hole is established, step up to progressively larger bits (e.g., 1/2‑inch, then 9/16‑inch) until the bolt head can be removed or the bolt can be fully drilled out.

Do I need special lubricants or cooling when drilling a Grade 8 bolt?

Yes. Use a high‑quality cutting fluid or petroleum‑based lubricant (e.g., WD‑40, Kroil, or a dedicated metal‑cutting oil). Apply the lubricant generously to the drill bit and the bolt to reduce friction, lower temperature, and extend bit life. If possible, use a low‑speed setting (around 300–500 RPM for a ½‑inch bit) and allow the lubricant to keep the cutting zone cool.

Can I use a regular HSS drill bit for a Grade 8 bolt?

While a standard HSS bit can eventually drill through a Grade 8 bolt, it will wear out quickly, generate excessive heat, and may break. The hardened steel of a Grade 8 bolt is designed to resist deformation, and ordinary HSS lacks the heat‑resistance needed for efficient cutting. For reliable results and to avoid damaging your tools, a cobalt‑alloy HSS bit or carbide bit is strongly recommended.

What safety precautions should I follow when drilling out a Grade 8 bolt?

1. Wear safety glasses and hearing protection. 2. Secure the workpiece firmly in a vise or clamp to prevent rotation. 3. Use a drill press whenever possible for better control and alignment; if using a hand drill, keep the bit perpendicular to the bolt. 4. Apply cutting fluid continuously to avoid overheating. 5. Start at low RPM and increase gradually only if the bit cuts cleanly. 6. Keep hands and clothing away from the spinning bit, and be prepared for the bit to bind or break—have a fire‑resistant mat beneath the work area.