When working with hardened steel, choosing the right drill bit material is essential for effective, clean drilling and tool longevity. Hardened steel requires bits that can resist high heat, maintain sharpness, and withstand wear. This article reviews some of the best drill bit materials and sets designed specifically for hardened steel, stainless steel, and other tough metals. The table below summarizes the key features of the top 5 recommended drill bit sets available on Amazon for drilling hardened steel.
| Product | Brand | Material | Key Features |
|---|---|---|---|
| BOSCH CO14B 14-Piece M42 Cobalt Drill Bit Set | BOSCH | M42 Cobalt Alloy | High heat resistance, 10x longer life, durable for stainless steel and titanium |
| Sinyeenglon 99Pcs M35 High Speed Steel Cobalt Drill Bit Set | Sinyeenglon | M35 Cobalt HSS | Up to 12x life vs titanium coated bits, hardened full grinding, sharp durable bits |
| COMOWARE 15Pcs M35 Cobalt HSS Drill Bit Set | COMOWARE | M35 Cobalt HSS | 135° split point, gold oxide finish, prevents walking, ideal for hardened metals |
| Jerax Tools M2 High Speed Steel Step Drill Bit | Jerax Tools | M2 HSS with Vacuum Heat Treatment | Enhanced durability by tungsten/molybdenum, nitride surface hardening, polished steps |
| Mars-Tool 2/Pack Solid Carbide Drill Bit for Hardened Steel | Mars-Tool | Solid Tungsten Carbide | Extreme heat resistant, four facet point, superior rigidity and chip removal for aircraft metals |
BOSCH CO14B 14-Piece M42 Cobalt Drill Bit Set
The BOSCH CO14B drill bit set stands out due to its M42 cobalt alloy composition, which includes 8% cobalt for improved durability and heat resistance. Designed for demanding materials like stainless steel, titanium, and hardened steel, these bits offer 10 times longer life than standard drill bits. Their high-heat resistance makes them ideal for extended drilling periods without losing sharpness.
The bits feature a three-flat shank, improving grip and reducing slippage during use. Their jobber length makes them versatile for various applications. This set is especially useful for metalworkers and industrial tasks requiring reliability against hard and abrasive surfaces.
Sinyeenglon 99Pcs M35 High Speed Steel Cobalt Drill Bit Set
Made from M35 cobalt high-speed steel, the Sinyeenglon set offers exceptional hardness with a rating up to 67 HRC. This allows faster cutting speeds and a lifespan up to 12 times longer than titanium-coated bits. The bits undergo a hardened full grinding process, enhancing wear resistance and sharpness for use on tough materials like hardened steel, stainless steel, and titanium.
With 99 pieces ranging from 1/16″ to 3/8″, this comprehensive kit comes neatly organized in a durable plastic case. It serves well for professionals needing a wide size range and long-lasting performance for heavy-duty metal drilling.
COMOWARE 15Pcs M35 Cobalt HSS Drill Bit Set
The COMOWARE drill bit set is crafted from 5% cobalt high-speed steel M35, giving it extended durability and heat resistance. Their 135° split point design prevents walking at the start of drilling and improves accuracy. A gold oxide finish reduces corrosion and supports chip clearance to maintain sharpness over prolonged use.
This set is ideal for hardened metals like stainless steel, cast iron, and titanium alloys but is also versatile enough for wood and plastics. The bits have round straight shanks for secure chuck holding and come in an indexed storage case for easy size identification and transport.
Jerax Tools M2 High Speed Steel Step Drill Bit
Jerax Tools offers a unique step drill bit made of M2 high-speed steel enhanced with vacuum heat treatment and nitride surface hardening. This combination improves durability significantly beyond standard M2 bits. The design features polished size markings on steps, allowing users to monitor hole size while drilling without stopping.
This bit excels in drilling through extra thick materials like stainless steel, copper, aluminum, wood, and plastics. Its polished steps and optimized geometry provide faster, cleaner holes with less heat generation. It is ideal for users needing multi-diameter holes in tough materials with precision.
Mars-Tool 2/Pack Solid Carbide Drill Bit for Hardened Steel
For the toughest drilling jobs on hardened steel and aerospace metals, Mars-Tool delivers solid tungsten carbide drill bits. These bits offer outstanding rigidity and heat resistance exceeding high-speed steel, suitable for dry or wet drilling applications. The four-facet 118° point minimizes drill wandering for highly accurate hole placement.
These jobber length bits are precision ground with spiral flutes designed for efficient chip removal and smooth finishes. They sustain sharpness over extended use on hard metals such as chrome, titanium, inconel, and stainless steel. They provide a professional-grade solution where standard HSS or cobalt bits may wear prematurely.
Buying Guide: Choosing the Best Drill Bit Material for Hardened Steel
1. Drill Bit Material
The material composition of a drill bit determines its strength, heat resistance, and wear life. For hardened steel:
- Cobalt Alloy Drill Bits (M35 or M42) are highly recommended as they contain cobalt which increases heat tolerance and hardness.
- High-Speed Steel (HSS) alone is suitable for softer metals but typically lacks necessary heat resistance for hardened steel.
- Titanium Nitride Coated Bits extend life compared to plain HSS but cannot match cobalt bits for very hard materials.
- Solid Carbide Bits offer superior hardness and heat resistance, ideal for extreme applications but are more brittle.
2. Drill Bit Geometry and Coating
The point angle and coating influence drilling performance:
- Split Point (135°) reduces walking and improves precision on hard steel.
- Coatings such as titanium nitride or gold oxide improve durability and reduce wear.
- Built-in chip clearance grooves help avoid overheating and bit clogging.
3. Heat Resistance and Durability
Hard metals create friction and heat during drilling that can dull bits quickly. Selecting bits that maintain hardness above 600°F (300°C) is crucial for:
- Longer bit life
- Cleaner holes with less burring
- Reduced work interruptions for sharpening
4. Drill Bit Sizes and Applications
Choose a kit that covers the size range needed for your project. Step drill bits can offer multi-size holes with one bit but may not be as precise for very small sizes. Jobber length bits provide balance between strength and reach.
5. Storage and Organization
Sets with indexed and sturdy cases protect drill bits from damage and make size selection easier, improving workplace efficiency.
6. Intended Usage
Consider what materials you will drill most frequently. Cobalt M35/M42 bits excel on hardened steel, stainless steel, and titanium alloys. Carbide bits are preferred for aerospace and abrasive metals. For occasional use on hardened steel, coated titanium bits may suffice at a lower cost.