Step drill bits Bosch HSS with 3-flat shank (model 2608597519)

Bosch HSS step drill bits with a 3-flat shank are designed for progressive drilling and enlarging of holes in thin materials. Made from high-speed steel, the stepped geometry allows drilling several diameters with a single tool and produces smooth, burr-reduced holes. The split-point tip provides fast centre positioning without pre-punching, while the CNC-ground spiral flute promotes effective chip evacuation and reduced vibration for even drilling action. Laser-marked diameter indicators in the spiral flutes ensure clear, durable size identification during work.

Advantages

The HSS construction delivers high hardness and wear resistance suitable for repeated use when coolant is applied. Axial and radial relief grinding ensure consistent cutting performance and smooth hole edges. The split-point tip enables immediate engagement and reduces walking on start. The 3-flat shank prevents slipping in chucks that accept this shank form and improves torque transmission, while the spiral flute geometry supports optimised chip removal for cleaner holes and less heat build-up.

Suitable for

• Drilling and enlarging holes in non-ferrous metals
• Working with sheet steel and stainless steel thin sheets
• Cutting holes in sheet plastics and plastic panels
• Workshop and installation tasks requiring multiple hole diameters with one tool

Key specifications

• Material: High-speed steel (HSS)
• Shank type: 3-flat shank for improved chuck grip and torque transfer
• Cutting geometry: Split-point tip for reduced walking and no pre-punching
• Flute design: CNC-ground spiral flutes for optimised chip evacuation
• Markings: Laser-marked diameter indicators in flutes for easy size reading
• Intended material thickness: Thin sheets and panels (metals and plastics)

How to use

Secure the step drill bit in a compatible drill chuck that accepts a 3-flat shank, ensuring firm clamping to prevent movement. Select the appropriate rotational speed and, where applicable, apply coolant or lubricant to extend tool life and reduce heat. Start drilling with light pressure to allow the split-point tip to engage the material, then increase pressure steadily while following the stepped diameters to reach the required hole size. Withdraw the bit periodically to clear chips and maintain a consistent cutting action.

Usage recommendations

For best results use on thin materials such as non-ferrous metals, sheet steel, stainless steel thin sheets and plastics. Apply cutting fluid when machining metals to improve life and surface finish. Avoid excessive lateral force; let the stepped geometry and correct speed do the cutting. Ensure the drill is compatible with a 3-flat shank to prevent slippage and maintain accurate hole sizing.