Drill bit Bosch HSS-Co 135 8.5 mm x 75 mm, cobalt high-speed steel, for metal

Bosch HSS-Co 135 8.5 mm x 75 mm drill bit is a cobalt-alloy high-speed steel tool engineered for drilling metal and other hard materials. With an 8.5 mm cutting diameter and 75 mm overall length, this drill bit combines cobalt-enhanced material properties with a 135° tip geometry to provide improved heat resistance, wear performance and accurate centring during drilling. The tool is intended for workshop and professional metalworking tasks where consistent hole quality and durability are required.

Advantages

The cobalt high-speed steel composition increases red hardness and thermal stability, making the drill bit better suited to persistent use on stainless steel and other tough materials. The 135° split-point tip geometry reduces walking at the start of drilling and improves centring accuracy without the need for a pilot hole. The solid construction and precision-ground flutes provide efficient chip evacuation and steady cutting action, extending tool life under demanding conditions.

Suitable for

• Drilling holes in stainless steel and alloyed steels
• Workshop and professional metal fabrication
• Drilling through hardened or heat-treated metal sheets and plates
• General maintenance and repair tasks involving metal components

Key specifications

• Cutting diameter: 8.5 mm
• Total length: 75 mm
• Material: cobalt-alloy high-speed steel (HSS-Co)
• Tip angle: 135° split-point geometry for precise centring
• Flute style: precision ground for improved chip removal

How to use

Select an appropriate drill speed for the material being machined and secure the workpiece firmly in a vise or with clamps. Use adequate cutting fluid or coolant when drilling stainless steel or other hard alloys to reduce heat and improve tool life. Position the drill bit at the marked spot and start at low speed to establish the hole centre, then increase speed and feed with steady pressure. Withdraw periodically to clear chips and reapply coolant as needed. After use, clean chips from the flutes and store the bit in a dry location to prevent corrosion.

Usage recommendations

For best results on hardened or stainless steels, run the drill at moderate speeds with consistent coolant flow and avoid excessive axial force. Replace the bit if cutting edges become rounded or chipping appears to maintain hole quality and operator safety.