Irwin twist drill bit set 10 pcs, 4.2 mm diameter, model 10502522

Irwin twist drill bit set 10 pcs, 4.2 mm diameter, model 10502522 contains ten identical 4.2 mm HSS cobalt twist drill bits designed for repeated drilling tasks with hand or power drills. Each bit is made from high-speed steel with 5% cobalt to increase heat and abrasion resistance, and features a heavy-duty web and a 135° split point that reduces walking and starts drilling immediately. Manufactured to DIN 338 standard, the set is intended for general-purpose and tougher metal drilling where enhanced wear resistance and strength are required.

Advantages

The cobalt-enhanced HSS composition offers increased durability and better performance when drilling hardened or alloyed steels. The 135° split point and precision ground geometry provide accurate, straight holes and reduced need for pilot punching. The uniform 4.2 mm size supplied in a 10-piece set supports repetitive tasks or multi-user environments, reducing downtime for bit changes and simplifying inventory for workshops.

Suitable for

• Drilling holes in alloyed steel and other ferrous metals
• General metalworking and fabrication tasks
• Workshop and maintenance applications requiring multiple identical bits
• Manual and powered drilling where heat and abrasion resistance is needed

Key specifications

• Drill type: twist drill bit, HSS with 5% cobalt
• Diameter: 4.2 mm
• Overall length: 75 mm
• Point angle and type: 135° split point for reduced walking
• Shank: cylindrical shank for standard chucks
• Quantity: 10 pieces per set
• Standards: manufactured to DIN 338 drill specifications
• Suitable materials: alloyed steel, stainless steel, general metal

How to use

Secure the drill bit in a compatible chuck and tighten firmly before operation. Select appropriate drill speed and use cutting fluid when drilling hardened or stainless steels to reduce heat buildup and extend bit life. Start drilling at low speed to establish the hole, then increase speed as necessary while maintaining steady, moderate feed pressure. Withdraw the bit occasionally to clear chips when drilling deeper holes and inspect the bit for wear; replace bits in the set when cutting performance declines.

Usage recommendations

For best results on hardened or stainless steels, use lubricant or cutting oil, moderate speed, and steady pressure. When drilling thin sheet metal, support the workpiece to prevent deformation and use a backing board where appropriate. Store bits in their case to protect cutting edges and keep sizes organized.