9.7 мм Свердла середньої серії з кутом 12° по металу DIN 338 RH

Low Helix Jobber Drills DIN 338 RH

DIN 338 low helix jobber drills in RH execution are designed for drilling materials that benefit from a low helix angle, particularly hard, brittle or short-chipping materials. Their jobber-length construction provides a practical balance between rigidity, drilling depth and reach.

Applications:

Used for drilling through holes and blind holes in suitable short-chipping materials, including brass, bronze and selected cast irons. Suitability depends on the specific alloy, its hardness, the drill material and the manufacturer’s recommended application range.

Operating Principle:

As the drill rotates, its cutting edges remove material while the flutes provide a path for chips to leave the hole. The low helix geometry produces a less aggressive cutting action than a comparable high helix design, helping control engagement in suitable materials.

Diameter and Length:

The drill diameter determines the nominal hole size. Overall length and flute length vary with the selected size. Jobber-length drills offer greater reach than comparable stubby drills, while requiring careful control of alignment and tool overhang.

Cutting Section:

Short chips must be cleared from the hole to prevent accumulation and increased cutting resistance. Even when machining materials that produce broken chips, drilling depth and flute capacity affect evacuation. Use an appropriate withdrawal cycle when necessary.

Tool Geometry:

The RH execution features a low helix geometry. DIN 338 specifies the dimensional series for jobber-length twist drills. The exact helix angle, point angle, cutting material and surface treatment should be checked in the specifications of the selected drill.

Practical Recommendations:

Secure the workpiece and clamp the drill with the minimum overhang required. Maintain a steady axial feed and avoid lateral pressure. Select dry machining, lubrication or cooling according to the workpiece material and tool recommendations. Reduce feed near breakthrough to limit grabbing and edge damage.

Specifications:

• Tool type: low helix twist drill
• Series: jobber length
• Standard: DIN 338
• Execution: RH
• Flute geometry: low helix
• Diameter: depends on the selected size
• Overall length: depends on the selected size
• Flute length: depends on the selected size

Cutting Characteristics:

The low helix geometry supports controlled cutting in suitable short-chipping materials. Stable clamping, appropriate feed and regular chip removal help maintain hole quality and protect the cutting edges.

Cutting Parameters:

Select spindle speed and feed according to drill diameter, drill material, workpiece composition and hardness, hole depth and cooling conditions. Follow the manufacturer’s cutting data for the selected tool and material.

Suitable Operations:

• Drilling suitable brass and bronze alloys
• Drilling selected cast irons and other short-chipping materials
• Producing through holes and blind holes
• Preparing holes for subsequent tapping or reaming

Limitations:

Low helix geometry is generally less suitable for soft, ductile materials that produce long, continuous chips. The RH designation alone does not establish suitability for hardened steel. Available drilling depth depends on tool dimensions and chip evacuation conditions. Avoid side cutting, misalignment and excessive tool overhang.