Dohre External Cooling 2 Flutes Drills

This external coolant solid carbide drill is designed for stable and efficient drilling in steel and general metal applications.

By combining premium carbide substrate, self-developed high-performance coating, and optimized drill geometry, it delivers reliable cutting performance, long tool life, and excellent cost efficiency for shallow and medium-depth drilling.

Ideal for ≤ 3×D drilling, standard CNC machines, and applications without internal coolant supply.

1. Premium Carbide Substrate

• Manufactured from imported MG-grade carbide rods

• Ultra-fine grain size: 0.8 μm

• 10% cobalt content for excellent toughness and wear resistance

• Suitable for high-speed and stable drilling in steel materials

This substrate provides a good balance between hardness and toughness, ensuring consistent performance under general machining conditions.

2. Self-Developed High-Performance Coating

(Benchmarking Balzers DR Coating)

• Independently developed coating with in-house coating equipment

• Optimized for steel and general-purpose drilling

• Coating hardness: 2000–4000 HV

• Low friction coefficient: 0.05–0.15

• Effectively reduces:

• Tool wear

• Built-up edge

• Surface scratching

The coating ensures smooth chip flow and extended tool life in continuous production.

3. Optimized Drill Geometry for External Coolant

• Helix angle: 30°

• Point angle: 138.9°

• Double cutting edge design improves:

      • Cutting stability

      • Wear resistance

      • Chip control

• Equalized web design reduces drill wandering and improves hole accuracy

• Optimized for external coolant or dry-assisted machining

This geometry provides reliable performance in standard drilling operations.

4. Efficient Flute & Core Design

• Large rake angle: 16°

• Negative chamfer: -6°

• Variable core thickness: 30–40%

• Variable outer diameter: 0.8°

This design improves cutting smoothness and chip evacuation, especially in shallow and medium-depth holes.

5. Application Materials

Suitable for drilling:

• Mild steel

• Quenched and tempered steel

• Quenched and tempered stainless steel

• Cast iron

• Bearing steel

Recommended for general-purpose drilling and standard production environments.

To ensure stable performance, long tool life, and consistent quality, every external coolant carbide drill is produced under a fully controlled manufacturing and inspection system.

Precision Edge Preparation Technology

• Drill tips are manually edge-honed and chamfered to improve edge strength and reduce micro-chipping

• Final edge preparation completed by fully automatic passivation equipment

• Rubber-bonded diamond abrasive polishing process ensures uniform edge radius on all cutting edges

• Edge passivation tolerance strictly controlled within ±0.003 mm

• Optimized edge preparation improves:

       • Wear resistance

       • Cutting stability

       • Tool life in continuous production

Advanced Manufacturing Equipment

• Manufactured on German WALTER 5-axis CNC grinding machines

• High-precision grinding ensures:

• Accurate drill geometry

• Sharp and consistent cutting edges

• Smooth and stable drilling performance

• In-house grinding capability allows flexible production and OEM customization

Strict Quality Inspection & Control

• Geometry and profile inspection using WALTER HELICHECK PLUS (Germany)

• Profile accuracy and corner radius controlled within 3 μm

• 100% visual inspection at 300× magnification

       • No edge chipping

       • No serrations

         • No surface defects

       • In-house coating machines ensure full control over:

       • Coating thickness consistency

       • Adhesion reliability

       • Batch-to-batch stability

• Integrated inspection system guarantees consistent quality from raw material to finished product

Q1: What is an external coolant carbide drill?

A: An external coolant carbide drill uses coolant supplied from the machine's external nozzles to cool the cutting area. It is suitable for shallow to medium-depth drilling, especially on machines without internal coolant systems.

Q2: What drilling depth is recommended for this drill?

A:This drill is recommended for drilling depths of up to 3×D, where external coolant can effectively cool the cutting zone and evacuate chips.

Q3: Which materials is this drill suitable for?

A:It is suitable for machining:

•Mild steel

•Quenched and tempered steel

•Quenched and tempered stainless steel

•Cast iron

•Bearing steel

This drill is designed for general-purpose steel drilling applications.

Q4: What coating is used on this external coolant drill?

A:The drill features a self-developed high-performance coating, benchmarked against B-a-l-z-a-s DR coating, with a hardness of 2000–4000 HV and a low friction coefficient of 0.05–0.15, helping reduce wear and improve tool life.

Q5: Does this drill require a machine with internal coolant?

A: No. This drill is designed for standard CNC machines and conventional machining centers that do not support internal coolant supply.

Q6: Can you provide OEM or customized solutions?

A:Yes. We support OEM and customized solutions, including special diameters, lengths, point angles, coatings, and application-specific designs.

Looking for stable high quality carbide drill for steel?

Contact us now for samples, technical support,or oem solutions.