FIESTO HSS COBALT DRILL BIT - FOR METER & STAINLESS STEEL USE

More info

HSS Cobalt drill bits are an excellent choice for drilling into stainless steel, and are generally considered the best option for the job compared to standard High-Speed Steel (HSS) bits.

Here is a breakdown of why HSS Cobalt bits (often labeled as M35 or M42) are highly recommended for stainless steel, along with crucial drilling tips:

Why HSS Cobalt is Best for Stainless Steel
Stainless steel is tough to drill because it is very strong and tends to work-harden quickly—meaning the friction and heat from drilling make the material even harder as you cut. The addition of cobalt directly addresses this:

Superior Heat Resistance: The 5% to 8% cobalt alloyed throughout the high-speed steel (HSS) body gives the bit significantly higher heat resistance than a standard HSS bit. This is the most critical factor for stainless steel, as it prevents the drill bit from dulling rapidly and stops the stainless steel from work-hardening.

Increased Hardness and Durability: The cobalt increases the bit's overall hardness and wear resistance, allowing the cutting edge to stay sharp for a much longer time, even when dealing with abrasive materials like stainless steel and cast iron.

Through-Body Alloy: Cobalt bits are alloyed throughout the metal (not just a surface coating), so the enhanced properties remain even after the bit is sharpened.

Key Features to Look ForWhen purchasing an HSS Cobalt bit for stainless steel, look for these specific characteristics:

FeatureWhy it MattersMaterialM35 (5% Cobalt) or M42 (8% Cobalt) is the industry standard for drilling hard metals.

Point Angle135-degree split point is highly recommended.

This self-centering design prevents the bit from "walking" or slipping on the hard surface, and requires less pressure to start cutting.

DesignA robust twist drill bit design with effective helical flutes for good chip evacuation is essential.