5.4 Long series straight shank drills DIN 340 RN

Long Series Straight Shank Drills DIN 340 RN

DIN 340 long series twist drills in RN execution feature a straight shank and extended overall and flute lengths. They are designed for drilling metal workpieces where greater reach or drilling depth is required than a comparable jobber-length drill can provide.

Applications:

Used for drilling through holes and blind holes, reaching recessed surfaces and machining components with restricted access. Suitability for a particular metal depends on the drill material, coating, cutting geometry and manufacturer’s recommendations.

Operating Principle:

As the drill rotates, its cutting edges remove material while the spiral flutes carry chips away from the cutting zone. The extended length increases reach but also makes the tool more sensitive to deflection, runout and misalignment. Accurate positioning and stable support are essential for maintaining the drilling direction.

Diameter and Length:

The drill diameter determines the nominal hole size. Overall length and flute length vary with the selected size. Additional length can provide access to deeper features, but usable drilling depth also depends on chip evacuation, clamping requirements and machining conditions.

Cutting Section:

Long flutes provide an extended path for chip evacuation. As hole depth increases, chips become harder to remove and may pack inside the flutes. Use a suitable peck drilling or withdrawal cycle when required, leaving sufficient clearance for chips to exit the hole.

Tool Geometry:

DIN 340 specifies the dimensional series for long twist drills with straight shanks. RN identifies the tool execution. The exact point angle, helix angle, drill material and surface treatment should be checked in the specifications of the selected drill.

Practical Recommendations:

Secure the workpiece, check spindle runout and clamp the straight shank with the minimum overhang needed for access. Where necessary, prepare a suitable starting hole using a compatible shorter drill. Apply a controlled axial feed, use appropriate cutting fluid and withdraw the drill as needed to clear chips.

Specifications:

• Tool type: long series twist drill for metal
• Standard: DIN 340
• Execution: RN
• Shank type: straight
• Diameter: depends on the selected size
• Overall length: depends on the selected size
• Flute length: depends on the selected size

Cutting Characteristics:

The extended design provides increased reach with lower resistance to bending than a shorter drill of the same diameter. Stable alignment and effective chip evacuation help reduce wandering, vibration and tool overload.

Cutting Parameters:

Select spindle speed and feed according to drill diameter, tool material, workpiece material, hole depth and setup rigidity. Adjust the drilling cycle to maintain chip removal and allow cutting fluid to reach the cutting zone.

Suitable Operations:

• Drilling holes requiring additional reach
• Accessing recessed surfaces in metal components
• Producing through holes and blind holes within the tool’s working capacity
• Preparing deeper holes for subsequent machining

Limitations:

Extended length increases sensitivity to lateral loads and misalignment. Flute length alone does not determine maximum drilling depth. These drills are not intended for side milling or enlarging holes through lateral pressure. Deep holes and tight tolerances may require additional guidance, specialised tooling or a finishing operation.