18 mm Cobalt jobber drills DIN 338 RN HSSCo

Cobalt Jobber Drills DIN 338 RN HSSCo

DIN 338 cobalt jobber drills in RN execution are made from cobalt-alloyed high-speed steel (HSSCo) for drilling metal workpieces. The cobalt addition improves resistance to softening at elevated cutting temperatures, while the jobber-length design provides a practical balance between rigidity, drilling depth and reach.

Applications:

Used for drilling through holes and blind holes in steel, stainless steel and other metals within the manufacturer’s recommended application range. HSSCo is useful for materials that generate higher cutting temperatures, but suitability also depends on drill geometry, workpiece hardness and machining conditions.

Operating Principle:

As the drill rotates, its cutting edges remove material while the spiral flutes carry chips away from the cutting zone. The HSSCo cutting material retains hardness at elevated temperatures, helping the cutting edges withstand demanding drilling conditions. Hole quality still depends on alignment, runout, feed and chip evacuation.

Diameter and Length:

The drill diameter determines the nominal hole size. Overall length and flute length vary with the selected size. Jobber-length drills provide greater reach than comparable stubby drills, although increased overhang makes accurate clamping and stable guidance more important.

Cutting Material:

HSSCo contains cobalt as an alloying element throughout the tool material; it is not a surface coating. The exact cobalt content and steel grade depend on the selected product. Its resistance to heat does not eliminate the need for appropriate cutting speed, lubrication and cooling.

Tool Geometry:

DIN 338 specifies the dimensional series for jobber-length twist drills. RN identifies the tool execution. Point angle, helix angle, point grinding and any surface treatment should be checked in the specifications of the selected drill.

Practical Recommendations:

Secure the workpiece and clamp the drill with minimal necessary overhang. Maintain a steady axial feed and use cutting fluid suitable for the workpiece material. When drilling stainless steel, avoid prolonged rubbing without effective cutting, as this can promote work hardening. Clear chips regularly and reduce feed as the drill breaks through.

Specifications:

• Tool type: cobalt twist drill for metal
• Series: jobber length
• Standard: DIN 338
• Execution: RN
• Tool material: cobalt-alloyed high-speed steel (HSSCo)
• Diameter: depends on the selected size
• Overall length: depends on the selected size
• Flute length: depends on the selected size

Cutting Characteristics:

The HSSCo material offers improved resistance to heat-related softening compared with conventional HSS. Stable cutting conditions and effective chip removal remain essential for maintaining edge condition and hole quality.

Cutting Parameters:

Select spindle speed and feed according to drill diameter, workpiece material and hardness, hole depth and cooling conditions. Follow the manufacturer’s cutting data for the specific HSSCo grade and drill geometry.

Suitable Operations:

• Drilling through holes and blind holes in metal
• Machining steel and stainless steel within the recommended range
• Preparing holes for subsequent tapping or reaming
• Workshop and production drilling requiring increased heat resistance

Limitations:

HSSCo does not make the drill suitable for every hardened steel or heat-resistant alloy. Avoid lateral loads, misalignment and chip blockage. Available drilling depth depends on tool dimensions and chip evacuation, while tight hole tolerances may require a subsequent finishing operation.