Solid Carbide Deep Hole Drill Bits

Solid carbide deep hole drill bits are specially designed for high-precision drilling operations where deep hole accuracy, chip evacuation, and tool stability are critical. Compared with standard drills, deep hole carbide drills feature optimized flute geometry and stronger core structures, allowing stable drilling at high depth-to-diameter ratios.

At DOHRE, our deep hole carbide drills are manufactured using ultra-fine grain tungsten carbide, advanced coating technology, and high-precision CNC grinding to ensure excellent tool life and consistent drilling performance.

These drills bits are widely used for machining steel, stainless steel, cast iron, and alloy steel, making them suitable for industries such as automotive manufacturing, mold processing, and precision mechanical components.

Example available diameter:

• Ø3 mm

• Ø4 mm

• Ø5 mm

• Ø6 mm

• Ø8 mm

• Ø10 mm

• Ø12 mm

1. Ultra-Fine Tungsten Carbide Material

Our drills are manufactured using imported tungsten carbide rods with 0.8 μm ultra-fine grain size and 10% cobalt content. This material structure provides excellent wear resistance while maintaining sufficient toughness for deep hole drilling operations.

High quality carbide material allows the drill to perform reliably under high-speed cutting conditions.

2. Optimized Deep Hole Geometry

The drill features an optimized structure specifically designed for deep hole applications:

• 30° helix angle for improved chip evacuation

• 138.9° point angle for stable drilling entry

• Double cutting edge design for improved wear resistance

• Split point structure to reduce drilling resistance

This design helps prevent drill wandering and ensures smooth cutting performance during deep hole machining.

3. Advanced Flute Design

To ensure efficient chip evacuation in deep drilling operations, the drill incorporates:

• 16° large rake angle

• –6° negative chamfer edge

• 30–40% variable core thickness

• 0.8° variable outer diameter

These features improve drill rigidity while allowing chips to evacuate smoothly even at high drilling depths.

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.

1. 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

2. 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

3. 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 a deep hole carbide drill?

A: A deep hole carbide drill is a drill designed for high depth-to-diameter drilling operations, typically exceeding 5×D. These drills feature specialized geometry to ensure stable drilling and efficient chip evacuation.

Q2:What materials can deep hole carbide drills machine?

A: They are commonly used for machining steel, stainless steel, alloy steel, cast iron, and bearing steel.

Q3: What is the maximum drilling depth?

A: Standard deep hole carbide drills are available from 3×D to 12×D, while special designs can reach 30×D depending on the drilling conditions.

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