Drill bit Bosch HSS-CO 135 10.2 mm x 87 mm, cobalt high-speed steel

Bosch HSS-CO 135 10.2 mm x 87 mm is a cobalt-alloyed high-speed steel drill bit designed for stable, precise drilling in hard metals and demanding industrial applications. The 10.2 mm diameter and 87 mm overall length deliver a balance between reach and rigidity, while the cobalt content increases heat resistance and wear durability. The 135° split point geometry helps achieve accurate centring and reduces tendency to wander, making the bit suitable for both hand-held and machine drilling where consistent cutting performance is required.

Advantages

The cobalt-alloyed high-speed steel construction provides improved resistance to heat and wear compared with standard HSS, extending service life when drilling tough materials. The 135° split point reduces walking at the drill start, enabling more accurate hole positioning without a pilot hole in many cases. The combination of diameter and overall length offers good stiffness for straight holes while allowing sufficient penetration depth for common metalworking tasks.

Suitable for

• Drilling in stainless steel and hardened steels
• Metal fabrication and machine shop operations
• Maintenance and repair work on industrial equipment
• Hand drilling and drill press applications

Key specifications

• Material: cobalt-alloyed high-speed steel (HSS-Co)
• Tip geometry: 135° split point for improved centring
• Diameter: 10.2 mm
• Overall length: 87 mm
• Cutting application: designed for hard metals and demanding use

How to use

Select appropriate speed and feed rates for the material being drilled and secure the workpiece to prevent movement. Use a centre punch for precise positioning if needed, then clamp the drill bit firmly in the chuck. Begin drilling at low speed to establish the hole, then increase speed as recommended for the workpiece material while applying steady, moderate pressure. Use cutting fluid or coolant when drilling stainless or hard steels to reduce heat and prolong tool life. Clear chips regularly to avoid clogging and overheating.

Usage recommendations

For best results when drilling stainless and hardened steels, use appropriate cutting fluid and moderate speeds; avoid excessive feed that can cause bit breakage. Ensure the drill is held perpendicular to the workpiece for straight holes and replace the bit once wear or chipping reduces cutting efficiency.