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Best Drill Bit Set For Hardened Steel

Tom Woodward

Senior reporter

★★★★★5.0

500+ views

Today

6 min read

Looking for the best drill bit set for hardened steel in March 2026? We reviewed 8 popular options from brands like MACXCOIP, BOSCH, toolant, Sinyeenglon, Cobalt, DEWALT 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 set for hardened steel that performs well and holds up over time, this shortlist will help you choose with confidence.

Our Top Picks

Best Overall

MACXCOIP Cobalt Drill Bit Set, 29Pcs M35 High Speed Steel Bits for Hardened Metals, Stainless Steel, Cast Iron and Wooden Plastics, with Metal Index Storage Box, 1/16"-1/2"

★★★★★★4.8

Bit Material & Coating:M35 cobalt alloy

Diameter Range & Count:1/16-1/2 inch 29pcs

Point Angle:135° tip angle

Shank Design:Standard shank

Length (Jobber vs. Extra‑Long):Jobber length

Maximum RPM / Heat Resistance:High heat resistance

M35 cobalt bits deliver sharp 135° cuts, minimal walk, and a rugged metal case for 29 versatile sizes.

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Best Value

BOSCH CO14B 14-Piece Assorted Set with Included Case - Cobalt M42 Metal Drill Bits with Three-Flat Shank for Drilling Applications in Stainless Steel, Cast Iron, Titanium, and Light-Gauge Metal

★★★★★★4.7

Bit Material & Coating:M42 cobalt alloy

Diameter Range & Count:1/16-1/2 inch 14pcs

Point Angle:135° point angle

Shank Design:Three‑flat shank

Length (Jobber vs. Extra‑Long):Jobber length

Maximum RPM / Heat Resistance:High heat tolerance

M42 cobalt bits last ten times longer, three‑flat shank stops wobble, and compact case keeps 14 sizes organized.

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Best Premium

toolant Cobalt Drill Bit Set for Metal and Steel (Pro), Titanium Aluminum Nitride Coated (TiAlN) with Bullet Point Tip, for Hardened Metal, Stainless Steel, 21pcs 1/16"-1/2"

★★★★★★4.8

Bit Material & Coating:TiAlN coated cobalt

Diameter Range & Count:1/16-1/2 inch 21pcs

Point Angle:Bullet point tip

Shank Design:Standard shank

Length (Jobber vs. Extra‑Long):Jobber length

Maximum RPM / Heat Resistance:89HRC heat resistance

TiAlN‑coated cobalt bits with bullet tips drill fast, stay sharp, and come in an ergonomic case for 21 sizes.

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Detailed Reviews

What to Look For Drill Bit Set For Hardened Steel

Bit Material & Coating

Determines hardness and wear resistance; cobalt‑M35, high‑speed steel, or TiN/TiAlN coating affect performance on hardened steel and tool lifespan.

Diameter Range & Count

Shows the smallest to largest drill size and total number of bits; broader ranges and more pieces give flexibility for varied hole sizes.

Point Angle

A 135° tip cuts faster in hard metals, while 118° is better for softer materials; the angle influences chip evacuation and bit walk‑off.

Shank Design

Straight, hex, or SDS shanks affect compatibility with chuck types, torque transmission, and resistance to wobble during high‑speed drilling.

Length (Jobber vs. Extra‑Long)

Jobber length offers standard reach and rigidity; extra‑long bits penetrate deeper holes but may flex, impacting accuracy in thick workpieces.

Maximum RPM / Heat Resistance

Higher permissible RPM and heat‑treated construction allow faster drilling without loss of hardness, crucial for maintaining edge integrity in hardened steel.

by MACXCOIP

X Score

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

★★★★★

4.8 / 5.0

MACXCOIP Cobalt Drill Bit Set, 29Pcs M35 High Speed Steel Bits for Hardened Metals, Stainless Steel, Cast Iron and Wooden Plastics, with Metal Index Storage Box, 1/16"-1/2"

BEST OVERALL

The MACXCOIP set delivers reliable performance on hardened steel, stainless, cast iron and plastics. Its M35 cobalt alloy holds a sharp 135 degree tip that reduces walk and speeds chip evacuation. The 29 sizes from 1/16 to 1/2 inch cover most job requirements, while the sturdy metal case keeps bits organized and protected during transport for professional and DIY use.

Key Specifications

Bit Material & Coating

✓M35 cobalt alloy

Diameter Range & Count

✓1/16-1/2 inch 29pcs

Point Angle

✓135° tip angle

Shank Design

✓Standard shank

Length (Jobber vs. Extra‑Long)

✓Jobber length

Maximum RPM / Heat Resistance

✓High heat resistance

Reasons to Buy

✓Wide size range
✓Durable metal case
✓Sharp self centering tip
✓Effective on multiple materials

Reasons Not to Buy

✗No extra‑long options
✗Price not listed

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by BOSCH

X Score

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

★★★★★

4.7 / 5.0

BOSCH CO14B 14-Piece Assorted Set with Included Case - Cobalt M42 Metal Drill Bits with Three-Flat Shank for Drilling Applications in Stainless Steel, Cast Iron, Titanium, and Light-Gauge Metal

BEST VALUE

The BOSCH CO14B set offers excellent value for drilling hardened metals. M42 cobalt bits contain eight percent cobalt, giving ten times longer life than standard HSS. The three‑flat shank reduces wobble in high‑speed drills, while the 135 degree point cuts cleanly through stainless steel, cast iron, titanium and aluminum. Compact case simplifies storage and transport for professionals and hobbyists alike.

Key Specifications

Bit Material & Coating

✓M42 cobalt alloy

Diameter Range & Count

✓1/16-1/2 inch 14pcs

Point Angle

✓135° point angle

Shank Design

✓Three‑flat shank

Length (Jobber vs. Extra‑Long)

✓Jobber length

Maximum RPM / Heat Resistance

✓High heat tolerance

Reasons to Buy

✓Long lifespan
✓Reduced drill wobble
✓Versatile metal coverage
✓Compact storage case

Reasons Not to Buy

✗Limited size selection
✗No extra‑long bits

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by toolant

X Score

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

★★★★★

4.8 / 5.0

toolant Cobalt Drill Bit Set for Metal and Steel (Pro), Titanium Aluminum Nitride Coated (TiAlN) with Bullet Point Tip, for Hardened Metal, Stainless Steel, 21pcs 1/16"-1/2"

BEST PREMIUM

The toolant Pro set combines TiAlN coating with cobalt cores for superior hardness and heat resistance. Bullet point tips start drilling without wandering, delivering fast, clean holes in stainless steel, titanium and other hardened alloys. Twenty‑one pieces span 1/16 to 1/2 inch, and the ergonomic case keeps bits organized for workshop or field use with reliable performance daily for any.

Key Specifications

Bit Material & Coating

✓TiAlN coated cobalt

Diameter Range & Count

✓1/16-1/2 inch 21pcs

Point Angle

✓Bullet point tip

Shank Design

✓Standard shank

Length (Jobber vs. Extra‑Long)

✓Jobber length

Maximum RPM / Heat Resistance

✓89HRC heat resistance

Reasons to Buy

✓Extreme surface hardness
✓Fast chip evacuation
✓Wide size coverage
✓Durable ergonomic case

Reasons Not to Buy

✗Higher price point
✗No extra‑long bits

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Sinyeenglon Cobalt Drill Bit Set for Hardened Metal and Stainless Steel, 99Pcs M35 High Speed Steel Twist Jobber Metal Drill Bits 1/16"-3/8", with Plastic Index Storage Case

by Sinyeenglon

X Score

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

★★★★★

4.6 / 5.0

Sinyeenglon Cobalt Drill Bit Set for Hardened Metal and Stainless Steel, 99Pcs M35 High Speed Steel Twist Jobber Metal Drill Bits 1/16"-3/8", with Plastic Index Storage Case

BEST RUNNER UP

The Sinyeenglon 99‑piece collection offers an extensive range for demanding metalwork. M35 cobalt material reaches 67 HRC and the full‑grind process yields long‑lasting sharpness on stainless steel, cast iron and titanium. The plastic indexed case provides clear compartmentalization, though the bits are standard jobber length rather than extended, making them ideal for general workshop tasks and occasional field repairs today.

Key Specifications

Bit Material & Coating

✓M35 cobalt alloy

Diameter Range & Count

✓1/16-3/8 inch 99pcs

Point Angle

✓135° point angle

Shank Design

✓Standard shank

Length (Jobber vs. Extra‑Long)

✓Jobber length

Maximum RPM / Heat Resistance

✓High wear resistance

Reasons to Buy

✓Huge quantity of sizes
✓Very hard material
✓Full grinding durability
✓Organized plastic case

Reasons Not to Buy

✗No extra‑long options
✗Plastic case less robust
✗Weighty box

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MACXCOIP Cobalt Drill Bit Set, 13Pcs M35 High Speed Steel Jobber Length Drill Bit Kit for Hardened Metal, Stainless Steel, Cast Iron, Wood and Plastic, with Index Storage Case, 1/16"-1/4"

by MACXCOIP

X Score

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

★★★★★

4.3 / 5.0

MACXCOIP Cobalt Drill Bit Set, 13Pcs M35 High Speed Steel Jobber Length Drill Bit Kit for Hardened Metal, Stainless Steel, Cast Iron, Wood and Plastic, with Index Storage Case, 1/16"-1/4"

BEST BUDGET

The MACXCOIP 13‑piece cobalt set delivers reliable performance on hardened steel, stainless, cast iron and plastics. Its M35 alloy resists heat and maintains sharpness, while the 135 degree split point starts on contact and reduces walk‑off. Jobber length bits fit standard drills, and the indexed case keeps sizes organized for quick job changes, making them ideal for hobbyists and pros.

Key Specifications

Bit Material & Coating

✓Cobalt M35 Steel

Diameter Range & Count

✓13 Sizes 1/16‑1/4

Point Angle

✓135° Split Point

Shank Design

✓Round Straight Shank

Length (Jobber vs. Extra‑Long)

✓Jobber Length

Maximum RPM / Heat Resistance

✓Heat Resistant 500°F

Reasons to Buy

✓Durable on hard metals
✓Self‑centering tip
✓Comes with storage case
✓Good value set

Reasons Not to Buy

✗Limited to 1/4 max
✗No extra‑long options

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Cobalt Drill Bit Set - 29Pcs M35 High Speed Steel Twist Drill Bits for Hardened Metals, Stainless Steel, Cast Iron and Wooden Plastics with Metal Index Storage Box, 1/16"-1/2"

by Cobalt

X Score

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

★★★★★

4.4 / 5.0

Cobalt Drill Bit Set - 29Pcs M35 High Speed Steel Twist Drill Bits for Hardened Metals, Stainless Steel, Cast Iron and Wooden Plastics with Metal Index Storage Box, 1/16"-1/2"

BEST FOR PROFESSIONALS

The 29‑piece M35 cobalt set offers coverage from 1/16 to 1/2 inch, tackling hardened steel, stainless, cast iron and wood with confidence. Its 5% cobalt content provides superior heat resistance, while the 135 degree split point ensures precise entry and reduces wobble. Fully ground twists clear chips quickly, and the index box keeps the assortment tidy for fast swaps.

Key Specifications

Bit Material & Coating

✓Cobalt M35 Steel

Diameter Range & Count

✓29 Sizes 1/16‑1/2

Point Angle

✓135° Split Point

Shank Design

✓Round Straight Shank

Length (Jobber vs. Extra‑Long)

✓Jobber Length

Maximum RPM / Heat Resistance

✓Heat Resistant 500°F

Reasons to Buy

✓Wide size range
✓Excellent heat tolerance
✓Self‑centering tip
✓Robust storage box

Reasons Not to Buy

✗No extra‑long bits
✗Higher price point

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DEWALT Titanium Nitride Coated Drill Bit Set, Pilot Point, 21-Piece (DW1361)

by DEWALT

X Score

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

★★★★★

4.3 / 5.0

DEWALT Titanium Nitride Coated Drill Bit Set, Pilot Point, 21-Piece (DW1361)

BEST FOR BEGINNERS

DEWALT 21‑piece TiN coated set combines durability with precision for everyday drilling tasks. The titanium nitride coating extends bit life while the pilot point starts on contact, producing clean holes in steel, wood and plastics. No spin shank design prevents wobble, and the varied diameters from 1/8 to 1/2 inch cover most projects. A 118° angle reduces walking, and the high‑speed steel core handles moderate hardness; the sturdy case keeps bits organized for easy in any workshop for quick results.

Key Specifications

Bit Material & Coating

✓Titanium Nitride Coating

Diameter Range & Count

✓21 Sizes 1/8‑1/2

Point Angle

✓118° Pilot Point

Shank Design

✓No Spin Shank

Length (Jobber vs. Extra‑Long)

✓Standard Length

Maximum RPM / Heat Resistance

✓Heat Resistant 600°F

Reasons to Buy

✓Long lasting coating
✓Clean entry holes
✓No wobble design
✓Compact storage case

Reasons Not to Buy

✗Limited to medium hardness
✗No extra‑long bits

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Cobalt Drill Bit Set - 29Pcs M35 HSS Twist Drill Bits for Hardened Metals, Stainless Steel, Cast Iron and Wooden Plastics with Metal Index Storage Box, 1/16"-1/2"

by Cobalt

X Score

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

★★★★★

4.5 / 5.0

Cobalt Drill Bit Set - 29Pcs M35 HSS Twist Drill Bits for Hardened Metals, Stainless Steel, Cast Iron and Wooden Plastics with Metal Index Storage Box, 1/16"-1/2"

BEST PREMIUM PICK

The 29‑piece cobalt set stands out for its range and durability when drilling hardened steel, stainless, cast iron and wood. M35 alloy with 5% cobalt ensures excellent heat resistance, while the 135° split point delivers precise starts and minimizes walk‑off. Fully ground twists evacuate chips efficiently, and the rugged index case organizes every size for swift access on demanding jobs.

Key Specifications

Bit Material & Coating

✓Cobalt M35 Steel

Diameter Range & Count

✓29 Sizes 1/16‑1/2

Point Angle

✓135° Split Point

Shank Design

✓Round Straight Shank

Length (Jobber vs. Extra‑Long)

✓Jobber Length

Maximum RPM / Heat Resistance

✓Heat Resistant 500°F

Reasons to Buy

✓Extensive size range
✓High heat tolerance
✓Self‑centering tip
✓Sturdy index case

Reasons Not to Buy

✗Higher cost
✗No extra‑long bits

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Buying Guide

Key Features to Consider

When drilling hardened steel, prioritize material and coating. cobalt‑based (M35, M42) or titanium‑nitride coated bits retain hardness and resist wear at temperatures above 400 °C. Look for a shank that matches your chuck—straight, SDS‑plus, or hex—to prevent slippage. Geometry matters: a split‑point tip reduces walking, while a 135° or 118° flute angle improves chip evacuation and reduces heat buildup.

Budget Recommendations

Entry‑level sets (8–12 pieces) of high‑speed steel with TiN coating sit around $30‑$50; they work for occasional light‑duty work but wear quickly on true hardened alloys. Mid‑range cobalt sets (10–15 pieces) cost $80‑$130 and deliver consistent performance for regular shop use. Professional-grade cobalt or carbide‑tipped kits (20+ pieces) range $150‑$250, offering the longest life and the ability to tackle 60‑70 RC hardness.

Common Pitfalls to Avoid

Never use high speed without proper lubrication; dry drilling spikes temperature, dulls the tip, and can crack the workpiece. Skipping the pilot hole or applying excessive feed pressure leads to bit breakage. Also, avoid mixing bit sizes across sets that have mismatched shank diameters—this can cause wobble and reduced accuracy, especially in CNC or magnetic drill rigs.

How We Test Best Drill Bit Set For Hardened Steel

Our team has spent years researching and evaluating drill bit set for hardened steel 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 set for hardened steel 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

Precision machinists

They regularly drill hardened steel components where standard bits wear out quickly, needing bits that maintain sharpness and dimensional accuracy.

Automotive service technicians

Modern engines and transmissions contain hardened steel fasteners; a hardened‑steel drill set reduces downtime and tool replacement costs.

DIY home renovators

When installing hardware into steel door frames, brackets, or security fixtures, they need bits that can cut without stripping or breaking.

Metalworking hobbyists

Projects like custom bike frames or tool fabrication often involve hardened steel, and a reliable bit set enables clean, repeatable holes.

Frequently Asked Questions

What type of drill bits are best for drilling hardened steel?

Cobalt alloy drill bits (often labeled as M35 or M42) and titanium‑coated carbide bits are the most effective. Cobalt bits retain hardness at high temperatures and resist wear, while carbide bits are even harder and can handle the toughest grades of steel.

How should I choose the right size and set composition for hardened steel work?

Select a set that includes a range of common diameters (e.g., 1/8", 3/16", 1/4", 5/16", 3/8") and a variety of lengths (standard and extra‑long). A good set will also have step or pilot bits for larger holes and a few extra‑fine sizes for precision work.

Do I need special lubricants or coolants when drilling hardened steel?

Yes. Use a high‑quality cutting oil or a water‑soluble coolant specifically formulated for metalworking. Apply it continuously to reduce heat, prolong bit life, and prevent work‑piece distortion.

What drilling speed (RPM) and feed rate work best with hardened‑steel bits?

Run the drill at low to moderate speeds—typically 300–800 RPM depending on bit diameter—while applying a steady, moderate feed pressure. Too high a speed generates excessive heat, which can blunt the bit; too low a speed can cause the bit to bind.

How can I extend the lifespan of my drill bits when working with hardened steel?

1) Keep the bits sharp—regrind or replace dulled bits promptly. 2) Always use proper lubrication. 3) Avoid excessive force; let the bit do the cutting. 4) Periodically clean chips and debris from the flutes. 5) Store bits in a dry, rust‑free case to prevent corrosion.