Drill bit GRAPHITE cobalt for metal, cylindrical shank, 7 mm (57H042)

GRAPHITE cobalt drill bit with a 7 mm diameter and cylindrical shank is designed for drilling metal in hand drills and drill presses. Made from high-speed steel with added cobalt, this drill bit offers increased heat resistance and improved wear performance compared with standard HSS bits. The bit is intended for machining steel and other ferrous materials where sustained cutting temperatures and hardness require a tougher cutting edge.

Advantages

The cobalt composition provides higher red hardness, allowing the drill bit to maintain cutting performance at elevated temperatures. The cylindrical shank ensures secure mounting in standard chucks and reduces runout when used in correctly aligned drilling equipment. The 7 mm diameter is a common size for through-holes and pilot holes in metalworking, and the bit’s geometry is optimized for efficient chip evacuation and sustained life under intermittent and continuous drilling conditions.

Suitable for

• Drilling holes in steel and other ferrous metals
• Workshop maintenance and repair tasks
• Use with hand drills and drill presses
• Industrial metalworking and fabrication

Key specifications

• Tip diameter: 7 mm
• Material: high-speed steel with cobalt alloy
• Shank type: cylindrical
• Intended material: steel and other ferrous metals
• Typical use: drilling with hand drills and drill presses

How to use

Secure the drill bit in the chuck so it sits straight and with minimal runout. Use appropriate cutting speed and feed for the metal being drilled; reduce speed and increase coolant or cutting fluid when drilling harder steels. Begin drilling with a moderate pressure to establish the hole, then maintain steady pressure while allowing the drill to cut without forcing. Withdraw periodically to clear chips and apply cutting fluid when necessary to manage heat and improve chip flow.

Usage recommendations

For best results, use cutting fluid or coolant when drilling stainless or hardened steels and avoid excessive spindle speed to prevent premature wear. Inspect the bit for wear or chipping before use and replace when cutting performance declines.