HSS Co Drill Bits: Specifications, Technical Insights, and Advantages

What Are HSS-Co Drill Bits?

HSS-Co drill bits are crafted from high-speed steel alloyed with 5–8% cobalt, a critical additive that significantly boosts their heat resistance and hardness. Unlike standard HSS bits, the cobalt infusion allows these tools to maintain their cutting edge even under extreme temperatures generated during high-speed drilling.

Key Specifications of HSS-Co Drill Bits

1. Material Composition:

• Base Material: M35 or M42 grade HSS (M42 contains 8% cobalt for superior performance).

• Cobalt Content: 5% (M35) to 8% (M42), enhancing red-hardness (retains hardness at high temps).

• Optional Coatings: TiN (Titanium Nitride) or TiAlN (Aluminum Titanium Nitride) for reduced friction and extended lifespan.

2. Size Range:

• Diameters: 1mm to 20mm (standard), with custom sizes available for industrial applications.

• Shank Types: Straight shank, reduced shank, or Morse taper for specialized machinery.

3. Hardness & Durability:

• Rockwell Hardness (HRC): 64–68 HRC (higher than standard HSS bits).

• Max Operating Temperature: Up to 600°C (1112°F) without losing edge sharpness.

4. Applications:

• Ideal for drilling: Stainless steel, titanium, hardened steel, cast iron, and non-ferrous metals.

Technical Advantages of HSS-Co Drill Bits

1. Superior Heat Resistance
   Cobalt’s ability to withstand high temperatures minimizes tool wear during prolonged use, even without coolant. This makes HSS-Co bits perfect for CNC machining or automated processes.

2. Enhanced Hardness & Wear Resistance
   The cobalt alloy structure resists deformation and edge chipping, ensuring consistent performance in abrasive materials.

3. Extended Tool Life
   Compared to standard HSS bits, HSS-Co variants last 3–5x longer, reducing downtime and replacement costs.

4. Versatility in Tough Materials
   From aerospace-grade titanium to automotive cast iron, HSS-Co drill bits handle challenging substrates with precision.

5. Compatibility with Coatings
   TiN or TiAlN coatings further reduce friction, lower operating temperatures, and prevent material adhesion (e.g., aluminum buildup).

Performance Comparison: HSS-Co vs. Standard HSS vs. Carbide

Best Practices for Using HSS-Co Drill Bits

• Speed & Feed Rates:

• Stainless Steel: 10–15 SFM (surface feet per minute).

• Cast Iron: 80–100 SFM.

• Always use cutting fluid for optimal heat dissipation.

• Drilling Tips:

• Start with a pilot hole for large diameters.

• Avoid excessive pressure to prevent work hardening of metals.

• Maintenance:

• Sharpen bits regularly using a diamond wheel.

• Store in a dry, rust-free environment.

Why Choose HSS-Co Over Alternatives?

For professionals tackling stainless steel fabrication, automotive repair, or heavy machinery maintenance, HSS-Co drill bits strike the ideal balance:

• ✅ Cost-effective for high-volume drilling.

• ✅ Durable enough to reduce tool changes.

• ✅ Flexible across multiple materials.