Drill bit set GRAPHITE 57H036-10 cobalt metal cylindrical 5.5 mm, 10 pieces

GRAPHITE cobalt metal drill bit set (10 pieces, 5.5 mm) contains ten cylindrical high-speed-drilling bits intended for metalworking tasks. Manufactured with a cobalt-alloy composition, these bits provide increased hardness and heat resistance compared with standard HSS drills, enabling sustained performance during high-speed drilling and when working with harder steels and alloys. The set is presented for use in workshops and industrial environments for drilling through plates, profiles and assembled components where consistent hole quality and tool life are required.

Advantages

The cobalt composition increases wear resistance and maintains cutting edge hardness at elevated temperatures, reducing the risk of rapid dulling during heavy use. Cylindrical shanks ensure secure clamping in standard chucks, while the 5.5 mm diameter offers a precise single-size solution for repetitive drilling tasks. The set of ten identical bits provides immediate replacements, minimising downtime in production or repair work.

Suitable for

• Drilling holes in steel plates and structural profiles
• Workshop and maintenance drilling on assembled equipment
• Operations requiring high-temperature stability and extended tool life
• Repetitive production drilling where identical hole size is needed

Key specifications

• Material: cobalt-alloy high-speed steel (cobalt-enhanced)
• Shank type: cylindrical (round) shank for standard chucks
• Diameter: 5.5 mm
• Quantity: 10 pieces per set
• Primary application: metal drilling (sheets, profiles, assemblies)

How to use

Select an appropriate drilling machine or handheld drill with a compatible chuck and securely clamp the 5.5 mm cylindrical shank. Mark and centre-punch the drilling point on the workpiece to prevent walking. Use cutting lubricant or cooling fluid when drilling harder steels to reduce heat buildup and extend bit life. Start drilling at low speed to establish the hole, then increase speed according to material and machine capabilities while maintaining steady, even feed pressure. After use, clean shavings from the flutes and store bits dry to avoid corrosion.

Usage recommendations

For best results on stainless and hardened steels, use a suitable cutting fluid and moderate feed to avoid overheating. Replace worn bits promptly to maintain hole accuracy, and inspect chuck clamping regularly to ensure concentricity and safe operation.