Can a regular drill bit penetrate hardened steel?

Drilling through hardened steel can often present a challenge for the average DIYer or professional. Hardened steel is extremely tough and durable, often used in applications where strength and resistance to wear are critical. In this article, we will explore the capabilities of regular drill bits in penetrating hardened steel, discussing the factors that affect their performance and exploring alternative options for successful drilling.

Understanding hardened steel

Before delving into whether regular drill bits can penetrate hardened steel, it is crucial to understand the nature of hardened steel itself. Hardened steel is a form of steel that has undergone a heat treatment process, called quenching and tempering, to achieve increased hardness and strength. This treatment involves rapid cooling and reheating, altering the steel’s crystal structure and enabling it to resist abrasion, deformation, and penetration.

Regular drill bits

Regular drill bits, commonly made from high-speed steel (HSS) or carbon steel, are designed for drilling through softer materials like wood, plastic, and even mild steel. Although these bits can puncture through many materials with ease, they often struggle to penetrate hardened steel due to its exceptional hardness and toughness. The typical flutes and cutting angles of regular drill bits might not be sufficient to make significant progress into hardened steel.

Factors affecting drill bit performance

Several factors influence the ability of a regular drill bit to penetrate hardened steel:

1. Hardness of the steel: Different grades of hardened steel have varying levels of hardness. Drill bits may be able to penetrate some lower hardness levels, but they may struggle with harder grades.
2. Drill bit material and composition: Regular drill bits made from HSS or carbon steel are suitable for drilling through softer materials but may not have the necessary hardness or toughness to penetrate hardened steel effectively.
3. Speed and feed rate: When drilling through hardened steel, using the correct speed and feed rate is crucial. Going too fast or too slow can both reduce the effectiveness of the drill bit. High speeds generate heat and can cause the drill bit to dull quickly, while excessively slow speeds create excessive friction and may cause the bit to bind or break.

Alternative options for drilling hardened steel

If regular drill bits are not the most effective option for drilling hardened steel, there are alternative options to consider:

1. Carbide drill bits: Carbide drill bits are specifically designed to drill through tough materials, including hardened steel. These bits are made from tungsten carbide, which is harder and more durable than regular drill bit materials. Carbide drill bits have special cutting geometries and can maintain their sharpness for longer, providing excellent performance when drilling hardened steel.
2. Cobalt drill bits: Another alternative worth considering is cobalt drill bits. These bits are made from high-speed steel (HSS) with added cobalt, providing increased heat resistance. Cobalt drill bits can handle higher drilling temperatures, making them suitable for drilling through hardened steel.

While regular drill bits may struggle to penetrate hardened steel effectively, there are alternative options available that can handle the task. Carbide and cobalt drill bits are specifically designed to handle the hardness and toughness of hardened steel, providing superior performance and durability. When faced with the challenge of drilling through hardened steel, it is essential to choose the appropriate drill bit for the job to achieve satisfactory results.