Drill bit set Bosch HSS Twist Drill Bits Ground — metalworking high-speed steel, ground tip

HSS Twist Drill Bits Ground are high-speed steel drills designed for precise metalworking. The precision-ground 135° self-centring split-point tip combines active cutting with accurate centring to prevent wandering and to produce clean holes. The split point removes the need for centre-punching or pilot drilling for diameters up to 10 mm. With a ground cutting edge, these HSS bits deliver faster drilling rates and lower feed pressure compared with standard chisel-edged HSS drills. They are suitable for use in drill stands and handheld drill drivers and are manufactured to DIN 338 with a cylindrical shank equal to the drill diameter.

Advantages

The 135° split-point tip provides immediate centring and reduces walking at the start of drilling. Precision ground cutting edges improve chip evacuation and enable up to 40% faster drilling and up to 50% lower feed pressure versus standard-ground HSS bits with chisel edges. The cylindrical shank fits drill chucks and stands, and the bits are suitable for a wide range of metals and hard plastics, ensuring consistent hole quality.

Suitable for

• Drilling alloyed and non-alloyed steel
• Drilling cast steel, cast iron and sintered iron
• Drilling malleable cast iron
• Drilling non-ferrous metals (e.g., aluminium, copper)
• Drilling hard plastics
• Use in drill stands and handheld drill drivers

Key specifications

• Material: High-speed steel (HSS)
• Tip angle: 135° split point (self-centring)
• Flute type: Type N (standard flute angle)
• Shank: Cylindrical, diameter equal to drill size
• Manufacturing standard: DIN 338
• Diameter tolerance: h8

How to use

Select the appropriate drill diameter and secure the bit in the drill chuck or drill stand so the shank is fully seated. For best results when drilling metal, use a steady feed and appropriate cutting speed for the material; apply cutting fluid where recommended to extend bit life and improve chip removal. For diameters up to 10 mm, the 135° split point typically eliminates the need for a centre punch or pilot hole; for larger diameters, consider pilot drilling when required by the workpiece. Clear chips frequently and avoid excessive side forces to maintain hole accuracy.

Usage recommendations

Use suitable cutting oil when drilling steel and higher-alloy materials, select proper rotational speed for the material hardness, and clamp the workpiece securely. Replace worn bits to maintain hole quality and avoid overheating by using intermittent drilling or backing off to clear chips.