Drill bit Proline 78085K, metal, Ø 8.5 mm, length 117 mm, 1 pc

Proline 78085K metal drill bit, diameter 8.5 mm and overall length 117 mm, is a single-piece high-speed steel tool with 5% cobalt content designed for drilling metal. The bit features a 135° point angle with chamfering adjustment for faster, more accurate starts and is produced entirely by grinding to ensure straightness and dimensional accuracy. Its construction provides high temperature resistance and improved wear life when machining hard-to-cut materials.

Advantages

The combination of HSS alloyed with 5% cobalt and precision grinding delivers high hardness, thermal stability and consistent hole accuracy. The 135° point angle with chamfering adjustment reduces walking at the start of drilling and speeds up marking and entry. The bit is suitable for use in standard drill chucks and its design supports drilling in high-alloy steels, titanium, acid-resistant and stainless steels, creep-resisting steels and cast iron with high durability.

Suitable for

• Drilling precise holes in high-alloy and stainless steels
• Workshop and repair jobs requiring a single specific-size metal bit
• Machining titanium and acid-resistant materials
• Drilling cast iron and other difficult-to-machine metals

Key specifications

• Material: high-speed steel (HSS) with 5% cobalt
• Cutting point angle: 135° with chamfering adjustment
• Diameter: 8.5 mm
• Overall length: 117 mm
• Manufacturing: fully ground flutes for high accuracy and straightness
• Temperature resistance: high, suitable for elevated cutting temperatures
• Compatibility: fits standard drill chucks

How to use

Secure the drill bit in a standard drill chuck ensuring concentric clamping and correct axial alignment. Select a suitable cutting speed and apply appropriate cutting fluid when machining stainless or heat-resistant alloys to reduce temperature and prolong tool life. Start drilling with light pressure to allow the 135° point to locate the hole, then increase feed gradually. Retract periodically on deep holes to clear chips and maintain coolant flow.

Usage recommendations

Use recommended cutting speeds and feeds for the specific workpiece material; employ cutting fluid for stainless, high-alloy and titanium materials; avoid excessive feed rates that may cause premature wear. Inspect the bit for wear before use and replace when cutting performance deteriorates.