4-39mm Step Drill HSS Spiral Flute 2 Cutting Edges 118° Point 90° Step Angle - Ruko GmbH

Take advantage of the combination of high‑speed steel robustness and spiral‑fluted chip evacuation together with a cross‑ground 118° tip for reliable hole starts and consistent step sizes; order the tool directly via Metav Werkzeuge or consult our specialists for application advice.

RUKO Step Drill Bit 4–39 mm — HSS spiral‑fluted stepped drill, 13 steps, two cutting edges

The RUKO Step Drill Bit 4–39 mm is a stepped drill designed to create and enlarge holes in incremental sizes with a single tool, making it suitable for time‑efficient hole production and quick sizing tasks in workshop environments

• HSS spiral‑fluted construction
• Cross‑ground tip for precise starts
• Shank with three flats for secure clamping

Accurate hole sizing with fewer tool changes

The stepped design with 13 steps spanning 4–39 mm provides a practical alternative to multiple twist drills, enabling progressive enlargement of holes without repeated tool changes. The stepped geometry (step angle 90°) creates defined diameters on each level, resulting in consistent hole sizes and reduced rework. For production tasks where setup time matters, this configuration supports faster throughput and less downtime per hole.

Reliable entry and cleaner finishes through improved geometry

A cross‑ground tip with a 118° tip angle reduces wander at drill entry, improving first‑pass accuracy and minimising surface damage. The spiral‑fluted design actively evacuates chips from the stepped profile, which lowers the risk of clogging and helps maintain a better surface finish on each step. These features together support dependable starting behaviour and a neater hole edge, especially during serial operations.

Secure clamping and stable machining performance

The round shank equipped with three flats permits secure retention in chucks and allows positive torque transfer without slipping. The two cutting edges share the cutting load, which helps to balance forces and reduce vibration during drilling. Stable clamping and balanced geometry contribute to improved runout characteristics and more predictable hole quality when used in standard drill presses or compatible machine spindles.

Durable HSS construction for routine workshop use

Manufactured from HSS, the tool combines wear resistance with re‑grindability for extended service life under normal operating conditions. The stepped form with clearly defined 90° step angles preserves step integrity across repeated cycles, while the moderate tip geometry serves general‑purpose drilling tasks. The result is a tool that delivers reliable performance and predictable maintenance intervals, supporting economical use in maintenance and light production applications.

For tailored advice on integrating the RUKO step drill into workshop workflows or to place an order, contact Metav Werkzeuge for specialist guidance and supply coordination.

Technical Data

• Article number: 4000601712NW
• Item description: Stufenbohrer Bohrber.4-39mm HSS Spiralnut Z.2 Stufen 13 RUKO
• Manufacturer: Ruko GmbH
• Packaging unit: 1
• UID: 4000601712NW

Facts

• Diameter range: 4–39 mm
• Steps: 13
• Number of cutting edges: 2
• Tip angle: 118°
• Step angle: 90°

Special features

• HSS material
• Spiral‑fluted (spiral groove)
• Cross‑ground tip (Kreuzanschliff)
• Shank with three flats for secure clamping

FAQ

What diameter range does the tool cover? The RUKO Step Drill Bit 4–39 mm covers diameters from 4 to 39 mm across 13 distinct steps for incremental sizing.

How many cutting edges and what tip geometry does it have? The tool features two cutting edges and a 118° tip angle, with a cross‑ground geometry to improve entry behaviour.

How is the shank designed for clamping? The shank includes three flats to ensure secure retention in chucks and reduce the risk of slippage during machining.

What chip evacuation and finish advantages does the design offer? The spiral‑fluted profile facilitates effective chip removal from the stepped zones, contributing to cleaner hole edges and fewer clogs.

Is the tool suitable for re‑grinding and routine maintenance? Constructed from HSS, the drill is suitable for standard re‑grinding practices to extend service life under routine workshop conditions.

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