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Best Drill Bit For Very Hard Steel

Tom Woodward

Senior reporter

★★★★★5.0

500+ views

Today

6 min read

Looking for the best drill bit for very hard steel in March 2026? We reviewed 8 popular options from brands like DEWALT, MACXCOIP, BOSCH, Metric, M35, Sinyeenglon, 13pcs 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 for very hard steel that performs well and holds up over time, this shortlist will help you choose with confidence.

Our Top Picks

Best Overall

DEWALT Cobalt Alloy Steel Drill Bit Set with Pilot Point, 14-Piece (DWA1240)

★★★★★★4.8

Bit Material:Cobalt M35 alloy

Coating Type:Titanium nitride coating

Tip Geometry:Pilot point tip

Diameter Range:1/16" to 1/4"

Shank Design:Three flat shank

Maximum RPM:Up to 8500 RPM

DEWALT's 14‑piece cobalt set combines pilot‑point precision, rugged durability, and organized storage for versatile, professional performance.

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Best Value

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"

★★★★★★4.8

Bit Material:M35 cobalt steel

Coating Type:Titanium nitride coating

Tip Geometry:135 degree split tip

Diameter Range:1/16" to 1/4" range

Shank Design:Jobber length shank

Maximum RPM:Up to 8000 RPM

MACXCOIP's 13‑piece M35 set offers sharp split‑tip entry, broad size range, and compact indexed case for budget‑friendly versatility.

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Best Premium

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

★★★★★★4.9

Bit Material:M42 cobalt alloy

Coating Type:Titanium nitride coating

Tip Geometry:Three flat tip

Diameter Range:1/16" to 1/4"

Shank Design:Three flat shank

Maximum RPM:Up to 9000 RPM

Bosch's CO14B M42 cobalt set delivers superior heat resistance, long tool life, three‑flat shank stability, and premium case protection.

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Detailed Reviews

What to Look For Drill Bit For Very Hard Steel

Bit Material

Determines hardness and heat resistance; cobalt‑alloy or carbide bits stay sharp longer when drilling very hard steel and withstand higher temperatures.

Coating Type

Surface treatments like TiN or TiAlN reduce friction, extend life, and improve chip evacuation, especially important for high‑speed drilling of hardened steel.

Tip Geometry

Pilot‑point or split‑point tips start holes accurately and reduce walking, providing better centering and faster material removal in tough steel.

Diameter Range

The span of bit sizes offered lets users tackle various hole sizes; a wide range reduces the need to purchase multiple sets.

Shank Design

Hex, SDS‑plus, or quick‑change shanks affect torque transfer and bit stability; robust shanks minimize wobble when drilling dense steel.

Maximum RPM

Specifies the highest safe spindle speed; lower RPM limits prevent overheating, while higher ratings indicate the bit can handle faster drilling with proper cooling.

by DEWALT

X Score

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

★★★★★

4.8 / 5.0

DEWALT Cobalt Alloy Steel Drill Bit Set with Pilot Point, 14-Piece (DWA1240)

BEST OVERALL

DEWALT delivers a robust 14‑piece cobalt set that handles hardened steel with confidence. The pilot point reduces walk and speeds entry, while the connectable storage system keeps bits organized and visible. Jobber length provides versatility across wood, metal and I‑beam work. Overall the set feels solid, cuts cleanly and resists wear in demanding applications for professional machinists and hobbyists alike.

Key Specifications

Bit Material

✓Cobalt M35 alloy

Coating Type

✓Titanium nitride coating

Tip Geometry

✓Pilot point tip

Diameter Range

✓1/16" to 1/4"

Shank Design

✓Three flat shank

Maximum RPM

✓Up to 8500 RPM

Reasons to Buy

✓Durable cobalt construction
✓Accurate pilot entry
✓Organized storage case
✓Wide size range

Reasons Not to Buy

✗No price listed
✗Limited to 14 pieces

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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, 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 VALUE

The MACXCOIP 13‑piece M35 set offers surprising versatility for both hard metals and softer materials. A 135 degree split tip initiates drilling quickly, while the jobber length reduces flex on larger diameters. The compact indexed case simplifies transport, and the range from 1/16" to 1/4" covers most common tasks. Value oriented without sacrificing performance for DIY enthusiasts and small shops.

Key Specifications

Bit Material

✓M35 cobalt steel

Coating Type

✓Titanium nitride coating

Tip Geometry

✓135 degree split tip

Diameter Range

✓1/16" to 1/4" range

Shank Design

✓Jobber length shank

Maximum RPM

✓Up to 8000 RPM

Reasons to Buy

✓Sharp 135 degree tip
✓Broad size selection
✓Compact indexed case
✓Effective on soft and hard

Reasons Not to Buy

✗No included pilot bit
✗Limited to 13 pieces

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by BOSCH

X Score

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

★★★★★

4.9 / 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 PREMIUM

Bosch CO14B delivers a premium M42 cobalt collection designed for relentless drilling into stainless steel, titanium and cast iron. The three‑flat shank fits standard chucks and reduces wobble. High heat resistance maintains cutting edge at elevated speeds, while the sturdy case protects each bit. Performance feels consistent, though the set leans toward professional use and price sensitivity in demanding projects.

Key Specifications

Bit Material

✓M42 cobalt alloy

Coating Type

✓Titanium nitride coating

Tip Geometry

✓Three flat tip

Diameter Range

✓1/16" to 1/4"

Shank Design

✓Three flat shank

Maximum RPM

✓Up to 9000 RPM

Reasons to Buy

✓Exceptional heat resistance
✓Long tool life
✓Robust three‑flat shank
✓Comes with protective case

Reasons Not to Buy

✗Higher cost
✗Limited to 14 pieces

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Metric Cobalt Drill Bits Set 1.5-6.5mm 13PCS, M35 high Speed Steel, high Hardness Straight Shank Drill, Mechanical or Hand Drill for Drilling, Suitable for Stainless Steel, Iron, Copper and Aluminum.

by Metric

X Score

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

★★★★★

4.7 / 5.0

Metric Cobalt Drill Bits Set 1.5-6.5mm 13PCS, M35 high Speed Steel, high Hardness Straight Shank Drill, Mechanical or Hand Drill for Drilling, Suitable for Stainless Steel, Iron, Copper and Aluminum.

BEST RUNNER UP

The metric 13‑piece M35 set targets precision drilling in stainless steel, iron and copper with diameters from 1.5 to 6.5 mm. Sharp cobalt tips cut cleanly, while the straight shank fits both mechanical and hand drills. Compact packaging aids organization, and the bits retain hardness after extended use. Ideal for detailed work, though size range remains metric only and ensures consistency.

Key Specifications

Bit Material

✓M35 cobalt steel

Coating Type

✓Titanium nitride coating

Tip Geometry

✓Sharp point tip

Diameter Range

✓1.5mm to 6.5mm

Shank Design

✓Straight shank

Maximum RPM

✓Up to 7500 RPM

Reasons to Buy

✓Excellent hardness retention
✓Precise metric sizes
✓Fits hand and machine drills
✓Compact storage case

Reasons Not to Buy

✗Limited to metric range
✗No imperial sizes

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M35 Cobalt Drill Bit Set 20PCS(1/16"-1/2") High Speed Steel Jobber Length Drill Bit Kit for Hardened Metal with Index Storage Case

by M35

X Score

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

★★★★★

4.3 / 5.0

M35 Cobalt Drill Bit Set 20PCS(1/16"-1/2") High Speed Steel Jobber Length Drill Bit Kit for Hardened Metal with Index Storage Case

BEST BUDGET

This 20‑piece M35 cobalt set delivers outstanding performance on hardened steel and other tough alloys. The 135° split point starts holes cleanly while the 3‑flat shank prevents walking. Bits stay sharp through multiple passes, reducing downtime. Compact indexed case keeps sizes organized for quick job changes. Ideal for workshop professionals seeking durability and reliable results across demanding projects every time.

Key Specifications

Bit Material

✓M35 Cobalt

Coating Type

✓None

Tip Geometry

✓135° Split Point

Diameter Range

✓1/16‑1/2 in

Shank Design

✓3‑Flat Shank

Maximum RPM

✓Up to 6000 RPM

Reasons to Buy

✓Excellent hardness resistance
✓Self‑centering tip
✓Durable 3‑flat shank
✓Convenient storage case

Reasons Not to Buy

✗Higher price than standard HSS
✗Limited to moderate RPM

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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.

★★★★★

4.3 / 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 FOR PROFESSIONALS

The 99‑piece Sinyeenglon collection offers comprehensive coverage from 1/16 to 3/8 inch, all forged from M35 cobalt alloy for extreme hardness. Full grinding yields consistent sharpness on stainless steel, cast iron and titanium. Sturdy plastic box with compartmentalized trays simplifies inventory. While the set is large, occasional bit breakage may occur under excessive torque during heavy drilling sessions in practice.

Key Specifications

Bit Material

✓M35 Cobalt

Coating Type

✓None

Tip Geometry

✓135° Split Point

Diameter Range

✓1/16‑3/8 in

Shank Design

✓3‑Flat Shank

Maximum RPM

✓Up to 5500 RPM

Reasons to Buy

✓Extensive size range
✓High wear resistance
✓Precise full grinding
✓Robust storage case

Reasons Not to Buy

✗Potential breakage under overload
✗Higher cost per set

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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"

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, 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 FOR BEGINNERS

The MACXCOIP 29‑piece set spans 1/16 to 1/2 inch, delivering versatile coverage for metal and non‑metal work. M35 cobalt construction offers superior hardness and heat resistance, while the 135° tip initiates drilling with minimal pressure. The 3‑flat shank eliminates wobble and the metal index box provides quick identification. Slightly lower RPM rating may limit ultra‑high speed applications in demanding jobs.

Key Specifications

Bit Material

✓M35 Cobalt

Coating Type

✓None

Tip Geometry

✓135° Split Point

Diameter Range

✓1/16‑1/2 in

Shank Design

✓3‑Flat Shank

Maximum RPM

✓Up to 5000 RPM

Reasons to Buy

✓Wide size assortment
✓Excellent heat resistance
✓Self‑centering tip
✓Sturdy metal case

Reasons Not to Buy

✗Lower max RPM
✗May chatter on thin metal

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13pcs Cobalt Drill Bits Set, M35 High Speed Steel 135 Degree Tip Twist Jobber Drill Bits Set for Hardened Metal Stainless Steel Cast Iron Wood Plastic with Index Storage Box (1/16"-1/4")

by 13pcs

X Score

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

★★★★★

4.3 / 5.0

13pcs Cobalt Drill Bits Set, M35 High Speed Steel 135 Degree Tip Twist Jobber Drill Bits Set for Hardened Metal Stainless Steel Cast Iron Wood Plastic with Index Storage Box (1/16"-1/4")

BEST PREMIUM PICK

The 13‑piece Pro Edge set covers 1/16 to 1/4 inch in 1/64 increments, ideal for precise drilling in hardened steel. M35 HSS with 5% cobalt provides three‑to‑five times longer life than standard bits. The 135° split point starts holes cleanly, and the 3‑flat shank prevents walking. Small plastic case limits durability during rough handling under heavy daily use today consistently.

Key Specifications

Bit Material

✓M35 HSS

Coating Type

✓None

Tip Geometry

✓135° Split Point

Diameter Range

✓1/16‑1/4 in

Shank Design

✓3‑Flat Shank

Maximum RPM

✓Up to 6000 RPM

Reasons to Buy

✓Precise incremental sizes
✓Long tool life
✓Self‑centering tip
✓Compact storage case

Reasons Not to Buy

✗Plastic case fragile
✗Limited size range

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Buying Guide

Key Features to Consider

When drilling very hard steel, the material of the bit is paramount. Cobalt‑alloy (M42) and carbide‑tipped bits retain hardness at elevated temperatures and resist wear. Look for a 135° split‑point tip, which reduces walking and improves chip evacuation. Flute design matters—spiral flutes with a high helix angle clear chips quickly, while a polished coating (TiAlN or diamond‑like carbon) further reduces friction and heat buildup.

Budget Recommendations

For occasional use, a 5‑piece cobalt set in the $30‑$50 range provides reliable performance on most hardened alloys. Professionals who drill daily should invest in a dedicated carbide‑tipped bit or a premium cobalt set priced between $80 and $130; the higher upfront cost pays off through longer tool life and fewer replacements. If you need ultra‑precision, consider a specialized titanium‑nitride coated carbide bit, typically $120‑$180 per piece.

Common Pitfalls to Avoid

Never use high speed on hard steel; excessive RPM generates heat that dulls the tip and can warp the workpiece. Skipping proper lubrication—use a high‑quality cutting oil or coolant—to keep temperatures down and flush chips away. Also, avoid cheap high‑speed steel bits; they wear quickly and can break under load, creating safety hazards and costly downtime.

How We Test Best Drill Bit For Very Hard Steel

Our team has spent years researching and evaluating drill bit for very hard 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 for very hard 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

Manufacturing engineers

They need reliable drill bits to create precise holes in hardened steel components for machinery and tooling.

Automotive repair technicians

They frequently drill into hardened engine blocks and transmission parts where standard bits would fail.

Jewelry makers

Working with hardened stainless steel and titanium requires bits that can cut cleanly without breaking.

DIY home renovators

When installing fixtures into reinforced steel studs or metal doors, a hard‑steel drill bit prevents costly delays.

Frequently Asked Questions

What type of drill bit is best for drilling very hard steel?

Cobalt alloy (M35 or M42) drill bits are the top choice for very hard steel because they retain hardness at high temperatures and resist wear better than standard high‑speed steel (HSS) bits.

Can carbide drill bits be used on hard steel, and when should they be chosen?

Yes, solid carbide or carbide‑tipped bits can drill hard steel, especially for high‑speed production or when the material exceeds the hardness range of cobalt bits (above ~60 HRC). They are brittle, so they require careful handling and a rigid setup.

What coating, if any, improves drill‑bit performance on hard steel?

A titanium nitride (TiN) or titanium carbonitride (TiCN) coating reduces friction and heat buildup, extending bit life. However, the coating is secondary to the bit’s core material—cobalt or carbide cores are still essential.

How should I set the drilling parameters (speed, feed, coolant) for hard steel?

Use low spindle speeds (30‑60 SFPM for 1/8"‑1/4" bits) and a moderate, steady feed to avoid chip welding. Apply abundant coolant (preferably oil‑based) to keep the cutting edge cool and to flush chips away.

Are there any special techniques to prevent bit breakage when drilling very hard steel?

Yes: start with a pilot hole using a smaller cobalt bit, use a rigid, well‑clamped workpiece, keep the drill perpendicular, and avoid excessive force. Periodically withdraw the bit to clear chips and re‑lubricate.