Drill bit set GRAPHITE 57H090 cobalt metal, cylindrical shank, assorted sizes 1.0–13.0 mm (set)

Set of GRAPHITE cobalt drill bits for metal with cylindrical shanks, covering diameters from 1.0 mm to 13.0 mm in a comprehensive assortment. The set includes a wide range of metric sizes for precise holemaking in steel and other ferrous materials. Manufactured from high-cobalt alloy, these bits are designed to offer improved heat resistance and longer wear life compared with standard high-speed steel drills, making them suitable for repeated drilling in demanding metalworking tasks.

Advantages

Cobalt composition increases hardness at elevated temperatures, reducing premature dulling when drilling hard or abrasive ferrous metals. Cylindrical shanks enable secure mounting in standard chucks and drill presses without special adapters. The broad size range from 1.0 mm to 13.0 mm minimizes the need to buy individual bits and supports stepped drilling for accuracy. Ground flutes and consistent geometry provide reliable chip evacuation and stable cutting action for cleaner holes and longer tool life.

Suitable for

• Drilling holes in steel and other ferrous metals
• Workshop and maintenance repair tasks
• Industrial and light fabrication metalworking
• Use in hand drills, drill presses and portable power tools with cylindrical chucks

Key specifications

• Material: cobalt alloy (high-cobalt HSS type)
• Shank type: cylindrical (straight shank) suitable for standard chucks
• Diameter range: 1.0 mm to 13.0 mm in assorted steps
• Intended use: drilling ferrous metals including steel
• Flute type: spiral ground for chip evacuation
• Finish: untreated/coated depending on manufacturing batch

How to use

Select the appropriate drill diameter for the required hole size and secure the bit in the drill chuck so the shank seats fully. Use a steady feed rate and appropriate spindle speed for the diameter and material — lower speeds for larger diameters and harder steels. Apply cutting fluid or lubricant when drilling steel to reduce heat buildup and extend tool life. Start with a pilot mark or center punch to prevent walking, and maintain steady pressure without forcing the bit; retract periodically to clear chips if drilling deep holes.

Usage recommendations

To maximize bit life and hole quality, use appropriate coolant or cutting oil, match drill speed to bit diameter and material hardness, and avoid excessive feed rates. Replace worn bits promptly to maintain accuracy and reduce risk of workpiece damage.