Cobalt Cylinder Drill Bit 7 mm 10 pcs – GRAPHITE 57H042-10

The Cobalt Cylinder Drill Bit 7 mm by GRAPHITE is a set of ten precision ground bits engineered for drilling in hard metals and tough alloys. These cylinder-style drill bits use a high-cobalt content steel that increases hardness and hot hardness, providing improved wear resistance and longer life under elevated cutting temperatures. The 7 mm diameter is suitable for common through-holes and pilot holes in metalworking tasks, and the pack of 10 ensures enough tools for small production runs, maintenance or workshop use.

Advantages

The high-cobalt composition delivers greater durability and heat resistance compared with standard HSS bits, reducing chipping and premature wear during high-speed drilling. The cylinder (walcowe) geometry offers stable cutting action and straightforward sharpening when necessary. Supplied as a 10-piece pack, the set provides consistent diameter accuracy across multiple operations and reduces downtime from frequent tool changes.

Suitable for

• Drilling stainless steel and hardened steel components
• Creating pilot holes prior to tapping or reaming
• Maintenance and repair work on machinery and metal structures
• Workshop and fabrication tasks requiring durable metal drills

Key specifications

• Diameter: 7 mm
• Quantity: 10 pieces per pack
• Material: high-cobalt high-speed steel
• Shank type: straight cylindrical shank suitable for standard chucks
• Intended use: drilling in hard metals and alloys

How to use

Secure the drill bit in the chuck of a hand-held drill or drill press, ensuring concentric clamping for accurate holes. Use appropriate cutting speeds and feed rates for the workpiece material—lower speeds for stainless and hardened steels to reduce heat buildup. Apply cutting fluid or coolant to improve chip evacuation and prolong bit life. Back the bit out periodically to clear chips and prevent clogging.

Usage recommendations

For best results, use a suitable cutting lubricant and moderate spindle speeds when drilling hard metals. Inspect bits regularly for wear and replace when edge rounding or chipping reduces hole quality.