Drill Bits Bosch HSS Twist Drill Bits Cobalt - set (model 2608585854)

Bosch HSS Twist Drill Bits Cobalt are high-speed steel twist drills with a cobalt-enhanced alloy designed for demanding metal drilling tasks. Manufactured to DIN 338 with a Type N flute geometry and a 135° split-point tip, these bits deliver precise centring, reduced walking and reliable chip evacuation thanks to two cutters and two flutes. The cobalt content increases heat resistance and wear performance, extending service life when working with stainless steels, alloyed and non-alloyed steels, cast iron and heat- or acid-resistant steels. The cylindrical shank matches the drill diameter for secure seating in drill stands and drill drivers.

Advantages

The cobalt-alloyed HSS construction provides improved hardness at elevated temperatures, resulting in higher wear resistance and longer tool life compared with standard HSS bits. The fully ground flutes and dual-cutter geometry promote fast, consistent chip removal and smooth cutting. The 135° split-point tip offers active cutting and accurate centring to minimise wandering at drill start. Cylindrical shank design allows stable clamping in standard drill chucks and stands.

Suitable for

• Drilling stainless steel and acid- or heat-resistant steels
• Drilling alloyed and non-alloyed steels
• Work on cast iron and cast steel components
• Metalworking, maintenance and repair operations requiring durable bits

Key specifications

• Material: high-speed steel (HSS) with cobalt alloy (approx. 5% cobalt)
• Geometry: Type N flute angle with two cutters and two flutes
• Tip: 135° split-point for improved centring and reduced walking
• Manufacturing standard: DIN 338 (ground twist drill)
• Shank type: cylindrical shank (shank diameter equals drill diameter)
• Tolerance: diameter tolerance class h8

How to use

Select the correct drill diameter for the hole required and secure the bit in a suitably rated drill driver or drill stand with a compatible chuck. For drilling stainless steel and other hard metals, use slow to moderate spindle speeds and apply steady, even feed pressure. Use cutting fluid or coolant to reduce heat build-up and extend bit life. Back the bit out periodically to clear chips when drilling deeper holes. Ensure workpiece is clamped securely to prevent movement during drilling.

Usage recommendations

Use cutting oil or an appropriate coolant when drilling stainless or alloyed steels to reduce friction and thermal stress. Start drilling at low speed to establish the centre, then increase speed within recommended ranges for the chosen diameter and material. Avoid excessive side loads and overheating to maintain tip geometry and prolong service life.