4-20mm Step Drill HSS-Co5 Spiral Flute 2-Cut 118° Tip 90° Step Angle - Ruko GmbH

Take advantage of the combination of durable HSS‑Co5 construction, a spiral flute for efficient chip evacuation and a secure shank with three gripping flats to reduce setup time and increase process reliability; order directly via Metav Werkzeuge or contact our consultants for application advice.

Ruko Step Drill Bit 4–20 mm (HSS‑Co5) with Spiral Flute and Cross‑Ground Tip

A Ruko Step Drill Bit 4–20 mm engineered to produce consecutive stepped holes in a single operation, combining cobalt‑alloyed high‑speed steel with spiral fluting and a cross‑ground 118° tip for clean starts and reliable centring

*HSS‑Co5 for increased wear resistance
*Spiral flute for improved chip removal
*Cross‑ground 118° tip for precise centring
*Covers 4–20 mm stepped hole range

Faster, more efficient stepped drilling with fewer tool changes

The HSS‑Co5 alloy provides enhanced red‑hardness compared with standard high‑speed steel, which supports sustained cutting performance under demanding conditions. As a result, the step drill reduces the need for frequent tool replacement and shortens production cycles. The bit's ability to deliver a continuous progression from 4–20 mm in stepped increments eliminates multiple operations with different tools, so machining sequences become simpler and throughput improves. This tangible efficiency is particularly relevant where process time and machine uptime drive production costs.

Controlled chip evacuation and cleaner hole quality

A spiral flute design channels chips away from the cutting edge and the hole, reducing clogging and heat build‑up during drilling. Combined with the cross‑ground geometry of the tip and its 118° angle, the tool centres reliably and initiates cuts cleanly, which helps minimise burr formation at each step. The two cutting edges maintain balanced cutting forces, supporting stable machining and consistent hole diameters across the stepped profile. For operations that prioritise repeatability, these features contribute directly to cycle stability and improved part quality.

Secure clamping and robust step geometry for repeatable results

The shank is provided with three gripping flats, enabling firm clamping in chucks and collets to prevent slippage during feed. The tool incorporates 9 steps with a 90° step angle, designed to produce defined step transitions while preserving flank integrity. This engineered geometry supports dependable centring and controlled material removal at each stage, which makes the bit suitable for production tasks that require precise, repeatable stepped holes. The combination of step count and geometry reduces set‑up variance and supports consistent part throughput.

For detailed application guidance or to arrange procurement of Ruko step drill bits, contact Metav Werkzeuge in Emmerich — email info@metav-werkzeuge.com or call +49 2822 7131930 for tailored advice and reliable supply

Technical data

• Article number: 4000601722NW
• Product: Stufenbohrer Bohrber.4-20mm HSS-Co5 Spiralnut Z.2 Stufen 9 RUKO
• Manufacturer: Ruko GmbH
• Packaging unit: 1

Core data

• Diameter range: 4–20 mm
• Tip angle: 118°
• Step angle: 90°
• Cutting edges: 2
• Steps: 9

Features

• Material: HSS‑Co5
• Spiral flute
• Cross‑ground tip
• Shank with 3 gripping flats
• Two cutting edges

FAQ

What hole sizes can be produced with this step drill bit?
The Ruko step drill bit creates stepped holes across the 4–20 mm range in a single tool, allowing consecutive diameters without changing cutters.

What does HSS‑Co5 mean for tool performance?
HSS‑Co5 indicates a cobalt‑alloyed high‑speed steel that delivers improved heat resistance and wear performance compared with standard HSS, extending tool life under higher thermal load.

How does the spiral flute affect drilling results?
The spiral flute improves chip evacuation and reduces heat accumulation, supporting cleaner holes and more consistent cutting action when using the step drill.

Is the tip suitable for accurate centring?
Yes. The cross‑ground geometry and 118° tip angle provide reliable centring and a clean start, which helps maintain concentricity through the stepped sequence.

What clamping arrangement is recommended for secure operation?
Use a chuck or collet that accommodates the shank with three flats to ensure firm clamping and prevent rotation during feed; this maintains repeatable step quality.

Manufacturer/Responsible: Ruko GmbH Präzisionswerkzeuge, Robert‑Bosch‑Strasse 7, 71088 Holzgerlingen