Twist drill bit, Irwin 10502507, 1 mm diameter, set of 2

Irwin 10502507 twist drill bit set includes two 1 mm diameter bits engineered for precise small-diameter drilling. These twist-style drill bits are manufactured to DIN 338 standards and combine a heavy-duty web construction with 5% cobalt in the matrix to increase heat and abrasion resistance. The 135° split point design reduces bit walk and starts cutting immediately, making the set suitable for demanding metalworking tasks where accurate 1 mm holes are required.

Advantages

The high-cobalt composition improves durability and performance when drilling abrasive or heat-generating materials. Heavy-duty web construction enhances strength and reduces the risk of breakage during push or torque loads. The 135° split point minimizes wandering at contact and ensures faster initial penetration without frequent repositioning. Compliance with DIN 338 ensures consistent geometry and reliable results across both pieces in the set.

Suitable for

• Fine metalworking and fabrication
• Electronics and PCB work requiring precise small holes
• Model making and precision hobby applications
• Drilling stainless and hardened metals where abrasion resistance is important

Key specifications

• Type: Twist drill bit
• Diameter: 1 mm
• Overall length: 34 mm
• Point angle and style: 135° split point
• Material enhancement: 5% cobalt for improved heat and abrasion resistance
• Shank type: Cylindrical shank
• Quantity: 2 pieces
• Manufacturing standard: DIN 338

How to use

Secure the 1 mm twist drill bit in a suitably sized chuck, ensuring concentric alignment and firm clamping. Use appropriate cutting speed and feed for small-diameter drilling in metal—lower speeds and steady, light feed reduce bit wear and risk of breakage. Apply cutting fluid or lubricant when drilling stainless or hardened steels to reduce heat buildup and improve chip evacuation. Back out the bit periodically to clear chips when drilling deeper holes and avoid excessive side loading.

Usage recommendations

For best results, start with a small pilot or use a center punch to prevent initial walk, maintain steady axial pressure, and use coolant when drilling abrasive or heat-sensitive materials. Store the bits in a protective case to prevent damage to the 1 mm cutting edges.