When working with hardened steel, stainless steel, or other tough metals, selecting the right drill bit is crucial to ensure efficient drilling, durability, and a clean finish. This article reviews the best drill bit sets designed specifically for drilling hardened steel, focusing on materials like cobalt and titanium coatings which improve heat resistance and lifespan. Below is a summary table of selected top-performing products for easy comparison.
| Product | Brand | Material & Features | Pieces |
|---|---|---|---|
| BOSCH CO14B 14-Piece Assorted Set | BOSCH | Cobalt M42, 8% cobalt, high heat resistance, three-flat shank | 14 |
| NordWolf 5-Piece M35 Cobalt Stubby Set | NordWolf | M35 cobalt steel, stubby size for tight spaces, 135° split point, hex shank | 5 |
| DEWALT Titanium Nitride Coated Set DW1361 | DEWALT | Titanium Nitride Coating, pilot point tip, no spin shank | 21 |
| toolant Titanium Aluminum Nitride Coated 21pc Set | toolant | M35 cobalt with TiAlN coating, bullet point tip, excellent heat resistance | 21 |
| WildBossy M35 Cobalt Drill Bit Set 20PCS | WildBossy | M35 cobalt, 135° split point, 3-flat shank, Ti surface | 20 |
BOSCH CO14B 14-Piece Cobalt M42 Metal Drill Bit Set
The BOSCH CO14B drill bit set features 14 bits made of premium Cobalt M42 steel alloy containing 8% cobalt, known for outstanding durability and high heat resistance. These bits are designed for drilling through hardened metals such as stainless steel, cast iron, and titanium. They possess a three-flat shank which provides a secure grip in the chuck and prevents slipping during operation.
This set excels in tough drilling jobs due to its cobalt construction which can withstand prolonged high-temperature use without losing sharpness or structural integrity. Its jobber-length design balances between reach and strength, ideal for general workshop use or industrial applications.
NordWolf 5-Piece M35 Cobalt Stubby Drill Bit Set for Hard Metals
The NordWolf M35 cobalt stubby drill bit set includes five compact drill bits optimized for difficult-to-access spots. Made from M35 cobalt steel, these bits are precision ground for enhanced toughness and longer lifespan when drilling through stainless steel and other hardened metals.
Stubby bit sizes range between 3/32″ and 5/16″ with a short length of 1.84 to 2.32 inches, providing better control and reduced vibration. The 135° split-point tip ensures self-centering and quick penetration without walking, ideal for accurate holes on hardened objects. Each bit holds a 1/4″ hex shank compatible with both quick-change chucks and impact drivers, expanding versatility.
DEWALT Titanium Nitride Coated Pilot Point Drill Bit Set
Known for durability and precision, the DEWALT Titanium Nitride Coated Drill Bit Set features pilot point tips that allow easier hole starts with cleaner edges. The set contains 21 drill bits with titanium nitride coating, which increases bit lifespan by reducing friction and heat buildup.
This set is ideal for drilling harder metals due to its combination of high-speed steel core and surface coating, which slows wear. The pilot point tips reduce walking and improve hole accuracy, while no spin shanks help maintain grip during heavy-duty drilling tasks.
toolant Titanium Aluminum Nitride Coated 21-Piece Cobalt Drill Bit Set
The toolant cobalt drill bit set offers exceptional performance thanks to its titanium aluminum nitride (TiAlN) coating, which enhances surface hardness to 89HRC and significantly improves heat resistance. These 21 bits come in sizes from 1/16″ up to 1/2″ with bullet point tips for smoother penetration in metals.
This cobalt alloy drill set is particularly effective on hardened steel, stainless steel, and titanium, combining cobalt toughness with advanced coating technology. Ideal for professionals seeking long-lasting bits with minimal sharpening needs, this set also includes various commonly used sizes for comprehensive coverage.
WildBossy M35 Cobalt Twist Drill Bit Set, 20 Pieces
The WildBossy M35 cobalt drill bit set comprises 20 pieces made from M35 high-speed steel alloy alloyed with molybdenum and cobalt to increase toughness and wear resistance. The bits feature a precise 135° split point for quick, accurate starts and a three-flat shank to prevent slipping in the drill chuck.
With Ti surface treatment and fully ground twists, these bits efficiently remove chips and maintain sharpness longer than traditional HSS bits. Covering a wide range of sizes, this kit suits both DIY and professional needs demanding robust performance on hardened metals.
Buying Guide for Drill Bits Used in Hardened Steel
Material Composition
Drilling hardened steel requires bits made from materials that can withstand high heat and resist wear. The most common are M35 cobalt steel (containing about 5% cobalt) and M42 cobalt steel (around 8% cobalt). These cobalt alloys maintain hardness at elevated temperatures, reducing the need for frequent sharpening. Titanium nitride and titanium aluminum nitride coatings provide additional protection, improving heat resistance and cutting efficiency.
Tip Geometry and Design
135° split-point tips are generally preferred for hardened steel drilling as they reduce walking and provide precision starts. Some bits feature bullet or pilot point tips to enhance centering and reduce surface damage. The flute design (two-flute vs. three-flute) impacts chip removal and heat dispersion, with three-flute bits offering smoother walls and better chip clearance for some applications.
Shank Type and Compatibility
Bits feature round shanks, three-flat shanks, or hex shanks. Three-flat shanks improve grip and reduce slippage, while hex shanks simplify quick changes, especially on impact drivers. Choosing a shank compatible with your drill chuck or device is vital for stable operation.
Size Range and Length
Consider the size range you need, from small precision holes to larger diameters. Jobber length bits offer standard reach balancing rigidity and access, while stubby bits are great for tight spaces, providing better control and reduced deflection.
Heat Resistance and Durability
Drilling hardened steel generates significant heat, so bits with coatings like TiN or TiAlN or made of cobalt alloys are critical for maintaining cutting edge sharpness and avoiding premature wear. Proper cooling techniques like using cutting oil can extend bit life.
Use Case and Application
Some drill bit sets are better suited for professional or industrial use with extensive size options and enhanced durability, while smaller sets with stubby bits fit tight, constrained environments. Matching the bit characteristics to your specific drilling needs is essential.