Drill bits Proline 78025K — metal bits, Ø 2.5 mm, length 57 mm, set of 3

Proline 78025K is a set of three metal drill bits with a 2.5 mm diameter and 57 mm overall length, designed specifically for drilling metal surfaces. Manufactured from high-speed steel with 5% cobalt (HSS-Co), these bits are intended for applications requiring high temperature resistance and consistent hole accuracy. The bits are fully ground to ensure rectilinearity and precision, and the 135° point angle with chamfering adjustment facilitates fast, controlled penetration and reduced walking at the start of drilling.

Advantages

The HSS steel with 5% cobalt increases heat resistance and wear life when working in high-alloy and difficult-to-machine metals. Full grinding of the drill flutes produces high concentricity and straight holes, while the 135° point geometry with chamfering adjustment helps shorten setup time and improves centring on metal surfaces. The 57 mm overall length balances reach and rigidity for light fabrication and repair tasks.

Suitable for

• Drilling holes in high-alloy steels, stainless and acid-resistant steels
• Working with titanium and creep-resisting steels
• Light fabrication, maintenance and installation tasks
• Use in hand drills and drill presses where a small-diameter metal bit is required

Key specifications

• Material: High-speed steel with 5% cobalt (HSS-Co)
• Diameter: 2.5 mm
• Overall length: 57 mm
• Point angle: 135° with chamfering adjustment
• Manufacturing: Fully ground flute and tip for accuracy
• Suitable work materials: High-alloy, stainless, acid-resistant, titanium, creep-resisting steels and cast iron (durability above 900 N/m²)
• Packaging: Blister pack containing three pieces of this size

How to use

Select the 2.5 mm Proline 78025K bit for the intended metal and secure the workpiece. Use an appropriate cutting fluid for metal drilling to reduce heat and improve chip evacuation. Fit the bit into the drill chuck, ensure it is clamped concentrically, and start at low speed to establish the centre using the 135° point geometry; increase speed as needed while maintaining steady feed. Apply consistent pressure without overloading the bit and clear chips periodically to maintain cutting efficiency and accuracy.

Usage recommendations

For best results when drilling high-alloy or stainless steels, use a coolant or cutting oil, moderate drilling speeds, and allow the bit to cool between prolonged passes. Inspect bits for wear and replace them when the cutting edge becomes rounded or performance declines to maintain hole quality and reduce risk of breakage.