Twist drill bit set Irwin 10502538 — 5 pieces, 10 mm diameter

Irwin 10502538 is a set of five 10 mm twist drill bits designed for general and heavy-duty metal drilling. The round-shank bits are made from HSS with 5% cobalt to increase heat and abrasion resistance, and feature a heavy-duty web construction for enhanced strength. With a 135° split point and DIN 338 manufacturing standard, these drills start cutting immediately and reduce walking when used in hand drills or drill presses to create 10 mm holes in compatible materials.

Advantages

The HSS cobalt composition (5% Co) delivers improved hardness and thermal stability compared with standard high-speed steel, allowing sustained cutting at higher temperatures and longer tool life when drilling abrasive or heat-treated metals. The heavy-duty web increases durability and resists breakage under load, while the 135° split point reduces bit wandering and provides faster penetration without excessive pressure. Conformance to DIN 338 ensures consistent geometry and reliable performance across the set.

Suitable for

• Drilling 10 mm holes in a variety of metals, including alloy and heat-treated steel
• Use with handheld electric drills and drill presses
• Workshop and professional maintenance tasks requiring durable twist bits

Key specifications

• Material: High-speed steel with 5% cobalt (HSS-Co)
• Diameter: 10 mm
• Quantity: 5 pieces
• Point angle: 135° split point for reduced walking
• Design standard: Manufactured to DIN 338 geometry
• Shank type: Round shank suitable for standard drill chucks

How to use

Secure the appropriate drill bit in the chuck ensuring it is centered and tightly clamped. Select a suitable cutting speed and feed rate for the material being drilled—slower speeds and steady pressure are recommended for hard or heat-treated metals. Use cutting fluid or coolant where applicable to reduce heat, improve chip evacuation and prolong bit life. Start drilling with light pressure to let the 135° split point locate the hole, then increase feed steadily until the hole is complete. Withdraw the bit periodically to clear chips when drilling deep holes.

Usage recommendations

For best results when drilling hardened or abrasive alloys, use appropriate coolant and moderate spindle speeds. Inspect bits regularly for wear or chipping and replace when cutting performance declines. Store the set in a dry place and handle bits carefully to avoid chipping the cutting edges.