Drill bit set GRAPHITE cobalt for metal, cylindrical shank 4.2 mm, 10 pcs

GRAPHITE cobalt drill bit set for metal includes 10 cylindrical-shank bits with a nominal diameter of 4.2 mm. These bits are made from high-speed steel with cobalt alloy to increase wear resistance and heat tolerance during drilling in steel and other metals. The set is intended for workshop, maintenance and construction tasks where a reliable metalworking drill is required. Cylindrical shanks ensure compatibility with standard chucks and quick change systems that accept straight shanks.

Advantages

The use of cobalt alloy in the cutting material improves hardness at elevated temperatures, reducing wear and extending usable life when drilling hard or abrasive metals. Precision ground flutes and point geometry provide stable cutting action and improved chip evacuation. The uniform 4.2 mm diameter across all 10 pieces allows straightforward replacement and consistent hole sizing for repetitive tasks. The cylindrical shank design offers secure clamping in a wide range of hand-held and bench drills.

Suitable for

• Drilling holes in carbon steel and alloy steel
• Maintenance and repair work in workshops
• Construction and metal fabrication tasks
• Applications requiring repeatable 4.2 mm holes

Key specifications

• Material: high-speed steel with cobalt alloy
• Shank type: cylindrical (straight) shank
• Nominal diameter: 4.2 mm
• Quantity: 10 pieces per set
• Application: drilling into steel and other metals

How to use

Select an appropriate drilling speed for the metal being worked; lower speeds are recommended for harder steels to avoid overheating. Secure the workpiece, clamp the bit firmly in the drill chuck, and apply steady, moderate pressure while drilling. Use cutting fluid or coolant when drilling thicker sections or hard alloys to improve lubrication and heat dissipation. After use, clean chips from flutes and store the bits dry to prevent corrosion.

Usage recommendations

For best performance, match drill speed and feed to the material: reduce speed for hardened steels and increase coolant flow when drilling long holes. Replace worn bits to maintain hole quality and reduce risk of breakage.