Bosch CO2159B 1/2-in x 6-in Cobalt M42 Drill Bit with Three-Flat Shank

Overview of the Bosch CO2159B Cobalt M42 Drill Bit

The Bosch CO2159B 1/2-in x 6-in cobalt M42 drill bit is built for demanding metalworking projects. Its upgraded M42 cobalt alloy, containing 8% cobalt, is formulated to resist heat and wear, helping you tackle hard metals with confidence. This jobber-length bit is designed to deliver consistent performance across stainless steel, cast iron, titanium, light-gauge metal, and aluminum, making it a versatile choice for shop benches and professional workstations.

Why this bit stands out

• 8% cobalt alloy delivers exceptional heat resistance and extended life compared with standard bits.
• High-heat endurance supports longer drilling sessions on tough metals.
• Thick web-helix design enhances stability and material removal for faster progress.
• Split point on sizes 1/8 in and larger reduces walking and eliminates the need for a center punch at start.
• Three-flat shank on 3/16 in and larger provides a secure grip in compatible chucks.

Material Compatibility and Use Cases

These cobalt bits excel when drilling hard and abrasive metals. Expect solid results in stainless steel and cast iron, with practical applicability to titanium and other challenging alloys. Aluminum and light-gauge metal can also benefit from the bit’s durability and controlled chip removal.

Design Details and Practical Tips

• Surface-hardened tip helps initiate penetration into tough surfaces with less skating.
• Split point and three-flat shank features are designed to make setup and operation smoother, especially in busy workshop environments.
• To maximize life, pair with appropriate drill speeds and lubrication, and avoid dry, high-heat runs on very hard materials.

Getting the Most from Your CO2159B

For best results, select the correct diameter and ensure the drill bit is properly secured. Use a steady feed and moderate cutting speed when working stainless steel, cast iron, or titanium. Let the bit do the work and avoid overfeeding, which can generate heat and wear. With its durable construction, this bit is designed for repeated use across multiple projects, from fabrication to maintenance tasks.